# Ferrum — Chemistry Education Platform (English Full Content) > Ferrum is a free chemistry education platform. This file is the comprehensive English LLM site map for ferrumone.com — all indexable `/en/...` pages (~130 URLs in sitemap-en.xml), tool capabilities, 118 element detail pages, JSON-LD schemas and cross-links. Primary site language is Turkish (YKS TYT/AYT exam prep, blog, study camps, PDF guides). Turkish maps: https://ferrumone.com/llms.txt and https://ferrumone.com/llms-full.txt. AI policy: https://ferrumone.com/ai.txt --- ## Homepage (English) **URL:** https://ferrumone.com/en **Title:** Ferrum | Chemistry Education Platform **Description:** Ferrum — free chemistry platform: interactive periodic table, mol/pH calculators, equation balancer, 3D simulations and personalized study tools. **Keywords:** chemistry education, periodic table, mol calculator, element quiz, chemistry simulations, interactive learning **hreflang:** en — alternate Turkish homepage at https://ferrumone.com/ ### Content Summary English homepage entry point for global chemistry search. Links to the interactive periodic table, mol/pH/gas-laws calculators, equation balancer, element quiz, 3D chemistry tools and About page. Most study content (blog, YKS camps, PDF document guides, simulations UI copy) remains Turkish-only; this file documents every English-indexable URL in sitemap-en.xml. **JSON-LD:** WebSite, EducationalOrganization, WebPage with hreflang alternates to Turkish routes. --- ## Page: Mol Calculator & Molar Mass Calculator **URL:** https://ferrumone.com/en/mol-calculator **Title:** Mol Calculator & Molar Mass Calculator | Ferrum **Description:** Free mol and molar mass calculator: enter a formula to calculate molar mass, moles, particles, STP gas volume and molarity. **Keywords:** mol calculator, molar mass, molarity, avogadro number, chemical formula, molar mass calculator **hreflang:** https://ferrumone.com/mol-hesaplayici (tr) ### Content Summary Free web tool for instant molar mass, mole count, particle count and gas volume (STP) calculations from a chemical formula. **Supported formula notation:** simple (H2O, NaCl), parentheses (Ca(OH)2, Al2(SO4)3), brackets (K4[Fe(CN)6]), hydrates (CuSO4·5H2O), nested groups (Mg3(Fe(CN)6)2). Case-sensitive: Co (cobalt) ≠ CO (carbon monoxide). **Molar mass output:** element contributions, Hill notation, empirical formula when reducible, mass % and atom % composition, total atom count. **Conversion modes:** mass→mol (n=m/M), mol→mass, particle count→mol (N/NA). Also computes particle count N and STP gas volume V=n×22.4 L/mol (0°C, 1 atm — high-school standard). **Molarity module:** c=n/V with L or mL volume input. **Step-by-step solutions** for every calculation. URL sharing via `?f=` query parameter. 40+ preset compounds (water, NaCl, CO2, H2SO4, NH3, CaCO3, etc.). **JSON-LD:** WebApplication, BreadcrumbList, FAQPage, HowTo. ### FAQ **How is mole count calculated?** n = m / M (mass in grams divided by molar mass in g/mol). **What is Avogadro's number?** Nₐ = 6.022 × 10²³ mol⁻¹ — particles per mole. **STP gas volume?** At 0°C and 1 atm, 1 mol ideal gas occupies 22.4 L. --- ## Page: pH Calculator & Acid-Base Table **URL:** https://ferrumone.com/en/ph-calculator **Title:** pH Calculator & Acid-Base Table | Ferrum **Description:** Strong/weak acid-base pH, buffer solutions (Henderson–Hasselbalch), pH-pOH-[H⁺]-[OH⁻] conversion and Ka/Kb table for 30+ substances. Step-by-step solutions. **Keywords:** pH calculator, acid base, buffer solution, Henderson Hasselbalch, Ka Kb table, chemistry exam prep **hreflang:** https://ferrumone.com/ph-hesaplayici (tr) ### Content Summary Five calculation modes: (1) strong acid, (2) strong base, (3) weak acid via Ka equilibrium, (4) weak base via Kb equilibrium, (5) buffer solution via Henderson–Hasselbalch pH = pKa + log([A⁻]/[HA]). Built-in Ka/Kb database for 30+ common acids and bases with autocomplete. Separate pH ↔ pOH ↔ [H⁺] ↔ [OH⁻] converter (Kw = 10⁻¹⁴ at 25°C). Color pH scale 0–14 with reference substances (stomach acid pH 2, blood pH 7.4, bleach pH 12.5). ICE tables and step-by-step solutions. **JSON-LD:** WebApplication, BreadcrumbList, FAQPage, HowTo. ### FAQ **How is pH calculated?** pH = −log[H⁺]. For strong acids, [H⁺] equals the acid concentration (with dilution correction below 10⁻⁶ M). **What is Henderson–Hasselbalch?** pH = pKa + log([conjugate base]/[acid]) for buffer solutions. **What is pOH?** pOH = −log[OH⁻]; at 25°C, pH + pOH = 14. --- ## Page: Gas Laws Calculator **URL:** https://ferrumone.com/en/gas-laws-calculator **Title:** Gas Laws Calculator — PV=nRT, Boyle, Charles, Avogadro | Ferrum **Description:** Free online gas laws calculator. Calculate ideal gas law (PV=nRT), Boyle, Charles and Avogadro with unit conversion and step-by-step solutions. **Keywords:** gas laws calculator, ideal gas, Boyle law, Charles law, Avogadro, PV=nRT, chemistry exam prep **hreflang:** https://ferrumone.com/gaz-yasalari-hesaplayici (tr) ### Content Summary Four modules in one tool: (1) Ideal gas PV=nRT — solve for any one of P, V, n, T; (2) Boyle P₁V₁=P₂V₂; (3) Charles V₁/T₁=V₂/T₂; (4) Avogadro V₁/n₁=V₂/n₂. **Units:** pressure atm/Pa/kPa/mmHg/bar; volume L/mL/m³; temperature K or °C (auto-converted). R = 8.314 J/(mol·K). STP quick-fill (0°C, 1 atm → 22.4 L/mol). Step-by-step solutions with unit conversions. **JSON-LD:** WebApplication, BreadcrumbList, FAQPage, HowTo. ### FAQ **Ideal gas law?** PV = nRT where R = 8.314 J/(mol·K). **STP molar volume?** 22.4 L/mol at 0°C and 1 atm (high-school convention). **Boyle's law?** At constant temperature, pressure and volume are inversely proportional: P₁V₁ = P₂V₂. --- ## Page: Chemical Equation Balancer **URL:** https://ferrumone.com/en/equation-balancer **Title:** Chemical Equation Balancer | Ferrum **Description:** Free online chemical equation balancer. Enter equations like Fe2O3 + C = Fe + CO2 to calculate coefficients automatically. Ionic equations, parentheses and brackets supported. **Keywords:** equation balancer, chemical equation balancing, stoichiometry, mass conservation, chemistry exam prep **hreflang:** https://ferrumone.com/denklem-dengeleyici (tr) ### Content Summary Balances equations via stoichiometric matrix + integer Gauss-Jordan elimination (BigInt arithmetic, no floating point). Supports parentheses, nested groups, ionic charges (Fe^3+, CO3^2-), electrons (e^-), phase labels (g,l,s,aq), arrows (=, →, ->, =>). Outputs atom balance verification table and mole ratios. URL sharing via `?eq=` parameter. Quick examples: H2+O2=H2O, N2+H2=NH3, combustion reactions. **JSON-LD:** WebApplication, BreadcrumbList, FAQPage, HowTo. ### FAQ **What is balancing?** Making atom counts equal on both sides by adjusting coefficients only. **Why integer coefficients?** Stoichiometric coefficients must be whole numbers representing mole ratios. --- ## Page: Element Quiz **URL:** https://ferrumone.com/en/element-quiz **Title:** Element Quiz | Ferrum **Description:** Match element symbols and names in a fast-paced quiz. Easy and hard modes, 10–100 questions, weak-spot mode and global leaderboard. **Keywords:** element quiz, element symbols, chemistry quiz, periodic table test, exam prep **hreflang:** https://ferrumone.com/element-testi (tr) ### Content Summary Multiple-choice quiz matching element symbols ↔ English names across all 118 elements. **Scope options:** all elements, by category (alkali metals, halogens, noble gases, lanthanides, actinides, etc.), by difficulty pool, weak-spot mode (logged-in users). **Question counts:** 10, 25 (guest); 50, 100, All (signed-in). **Modes:** symbol→name, name→symbol, mixed, weak spots. **Features:** countdown timer, accuracy stats, weak-element tracking (localStorage for guests; server sync when signed in), global leaderboard for authenticated users. **JSON-LD:** WebApplication, BreadcrumbList, FAQPage. --- ## Page: 3D Chemistry Tools (Hub) **URL:** https://ferrumone.com/en/3d-tools **Title:** 3D Tools — Molecule Viewer, Amino Acids, Lab Equipment | Ferrum **Description:** Explore chemistry molecules in 3D. Molecule viewer, amino acids, lab equipment and molecule editor. **Keywords:** 3D molecule viewer, amino acids, lab equipment, molecule editor **hreflang:** https://ferrumone.com/3d-araclar (tr) ### Content Summary Hub page listing four free 3D chemistry tools with feature cards and JSON-LD ItemList. All sub-tools require no login. | Tool | English URL | |------|-------------| | 3D Molecule Viewer | https://ferrumone.com/en/3d-tools/3d-molecule-viewer | | Amino Acids | https://ferrumone.com/en/3d-tools/amino-acids | | Lab Equipment | https://ferrumone.com/en/3d-tools/lab-equipment | | Molecule Editor | https://ferrumone.com/en/3d-tools/molecule-editor | --- ## Page: 3D Molecule Viewer **URL:** https://ferrumone.com/en/3d-tools/3d-molecule-viewer **Title:** 3D Molecule Viewer | Ferrum **Description:** Explore organic and inorganic molecules in 3D. Ball-stick, space-fill and more. **Keywords:** 3D molecule, ball stick, space fill, organic chemistry, PubChem ### Content Summary 45+ preset molecules (organic, inorganic, polymers, bioactive). View modes: ball-and-stick, stick, space-fill, wireframe. PubChem search by name or formula for 3D SDF structures. Rotate, zoom, pan. Category filters. Data source: PubChem. **JSON-LD:** WebApplication, BreadcrumbList, FAQPage. --- ## Page: Amino Acids — 3D Structures **URL:** https://ferrumone.com/en/3d-tools/amino-acids **Title:** Amino Acids — 3D Structures | Ferrum **Description:** Explore 3D structures, pKa values and biochemical classes of 20 standard amino acids. **Keywords:** amino acids, pKa, 3D protein, biochemistry, side chain polarity ### Content Summary Interactive 3D models of all 20 proteinogenic amino acids. Side-chain classification: nonpolar, polar uncharged, positively charged, negatively charged, aromatic/special. pKa values for α-COOH, α-NH₃⁺ and side chain where applicable. Molar mass and charge at physiological pH. **JSON-LD:** WebApplication, BreadcrumbList. --- ## Page: Lab Equipment — 3D Models **URL:** https://ferrumone.com/en/3d-tools/lab-equipment **Title:** Lab Equipment — 3D Models | Ferrum **Description:** Explore chemistry lab equipment in 3D. Erlenmeyer flasks, burettes, beakers and more. **Keywords:** lab equipment, erlenmeyer, burette, beaker, chemistry lab 3D, volumetric flask ### Content Summary Procedural 3D models of common lab glassware: beaker, Erlenmeyer flask, volumetric flask, burette, pipette, separatory funnel, Bunsen burner, test tube, round-bottom flask and more. Each item includes usage purpose, precision notes and safety reminders. Categories: measuring, heating, separation, storage, reaction. **JSON-LD:** WebApplication, BreadcrumbList. --- ## Page: Molecule Editor **URL:** https://ferrumone.com/en/3d-tools/molecule-editor **Title:** Molecule Editor | Ferrum **Description:** Draw molecules in 2D, convert to SMILES and inspect 3D structure. **Keywords:** molecule editor, Ketcher, SMILES, 2D 3D conversion, structure drawing ### Content Summary Ketcher-based 2D structure editor with live SMILES export and 3D preview. PubChem name/SMILES search, quick-pick common molecules, PNG export (signed-in users). Draw-on-left updates 3D view automatically. **JSON-LD:** WebApplication, BreadcrumbList. --- ## Page: About Ferrum **URL:** https://ferrumone.com/en/about **Title:** About Us | FerrumOne — The Digital Hub of Chemistry **Description:** Learn about FerrumOne's mission, vision and co-founders. The story of a global digital platform transforming chemistry education. **Keywords:** FerrumOne about, chemistry education platform, Yakup Demir, Turgay Tinas, digital chemistry platform **hreflang:** https://ferrumone.com/hakkimizda (tr) ### Content Summary Corporate about page with mission, vision and co-founder profiles. **Mission:** unify chemistry learning, research and tools on one platform — periodic table, calculators, quizzes, 3D models, simulations and study content. **Vision:** become global reference chemistry infrastructure. **Co-founders:** - **Yakup Demir** — chemistry education and content; Ferrum brand founder; Abant İzzet Baysal University chemistry graduate. - **Turgay Tınas** — technical architecture; ITU computer engineering; periodic table, calculators, 3D tools and panel infrastructure. **JSON-LD:** WebPage, AboutPage, BreadcrumbList, Person (two founders). --- ## Page: Interactive Periodic Table (English) **URL:** https://ferrumone.com/en/periodic-table **Title:** Interactive Periodic Table | Element Details, Atomic Numbers and Electron Configurations **Description:** Explore an interactive periodic table with element details, atomic numbers, electron configurations, atomic masses, categories and physical properties. **Keywords:** interactive periodic table, periodic table with element details, element atomic number, electron configuration, chemical elements, hydrogen element, helium element, lithium element, beryllium element, boron element, carbon element, nitrogen element, oxygen element, fluorine element, neon element, sodium element, magnesium element, aluminum element, silicon element, phosphorus element, sulfur element, chlorine element, argon element, potassium element, calcium element, scandium element, titanium element, vanadium element, chromium element, manganese element, iron element, cobalt element, nickel element, copper element, zinc element, gallium element, germanium element, arsenic element, selenium element, bromine element, krypton element, rubidium element, strontium element, yttrium element, zirconium element, niobium element, molybdenum element, technetium element, ruthenium element, rhodium element, palladium element, silver element, cadmium element, indium element, tin element, antimony element, tellurium element, iodine element, xenon element, cesium element, barium element, lanthanum element, cerium element, praseodymium element, neodymium element, promethium element, samarium element, europium element, gadolinium element, terbium element, dysprosium element, holmium element, erbium element, thulium element, ytterbium element, lutetium element, hafnium element, tantalum element, tungsten element, rhenium element, osmium element, iridium element, platinum element, gold element, mercury element, thallium element, lead element, bismuth element, polonium element, astatine element, radon element, francium element, radium element, actinium element, thorium element, protactinium element, uranium element, neptunium element, plutonium element, americium element, curium element, berkelium element, californium element, einsteinium element, fermium element, mendelevium element, nobelium element, lawrencium element, rutherfordium element, dubnium element, seaborgium element, bohrium element, hassium element, meitnerium element, darmstadtium element, roentgenium element, copernicium element, nihonium element, flerovium element, moscovium element, livermorium element, tennessine element, oganesson element ### Content Summary The English periodic table page is designed for global chemistry search intent. It keeps the same scientific data source as the Turkish periodic table while using English labels, English search terms and separate indexable `/en/...` URLs. Current English element detail pages: - [Hydrogen Element](https://ferrumone.com/en/element/hydrogen): Atomic number 1, symbol H, atomic mass 1.008, electron configuration 1s¹, uses, isotopes, compounds, study notes and FAQ. - [Helium Element](https://ferrumone.com/en/element/helium): Atomic number 2, symbol He, atomic mass 4.0026, electron configuration 1s², noble gas properties, uses, isotopes and FAQ. - [Lithium Element](https://ferrumone.com/en/element/lithium): Atomic number 3, symbol Li, atomic mass 6.94, electron configuration [He] 2s¹, alkali metal properties, uses, compounds and FAQ. - [Beryllium Element](https://ferrumone.com/en/element/beryllium): Atomic number 4, symbol Be, atomic mass 9.0122, electron configuration [He] 2s², alkaline earth metal uses, isotope, toxicity and FAQ. - [Boron Element](https://ferrumone.com/en/element/boron): Atomic number 5, symbol B, atomic mass 10.81, electron configuration [He] 2s² 2p¹, metalloid properties, allotropes, uses, isotopes, compounds and FAQ. - [Carbon Element](https://ferrumone.com/en/element/carbon): Atomic number 6, symbol C, atomic mass 12.011, electron configuration [He] 2s² 2p², allotropes, isotopes, biological role and FAQ. - [Nitrogen Element](https://ferrumone.com/en/element/nitrogen): Atomic number 7, symbol N, atomic mass 14.007, electron configuration [He] 2s² 2p³, atmospheric abundance, uses, isotopes and FAQ. - [Oxygen Element](https://ferrumone.com/en/element/oxygen): Atomic number 8, symbol O, atomic mass 15.999, electron configuration [He] 2s² 2p⁴, respiration, allotropes, paramagnetism, uses, isotopes, compounds and FAQ. - [Fluorine Element](https://ferrumone.com/en/element/fluorine): Atomic number 9, symbol F, atomic mass 18.998, electron configuration [He] 2s² 2p⁵, halogen properties, electronegativity, uses and FAQ. - [Neon Element](https://ferrumone.com/en/element/neon): Atomic number 10, symbol Ne, atomic mass 20.180, electron configuration [He] 2s² 2p⁶, noble gas properties, uses, isotopes and FAQ. - [Sodium Element](https://ferrumone.com/en/element/sodium): Atomic number 11, symbol Na, atomic mass 22.990, electron configuration [Ne] 3s¹, alkali metal properties, uses, isotope, compounds and FAQ. - [Magnesium Element](https://ferrumone.com/en/element/magnesium): Atomic number 12, symbol Mg, atomic mass 24.305, electron configuration [Ne] 3s², biological role, uses, isotopes, compounds and FAQ. - [Aluminum Element](https://ferrumone.com/en/element/aluminum): Atomic number 13, symbol Al, atomic mass 26.982, electron configuration [Ne] 3s² 3p¹, lightweight metal uses, isotope, compounds and aluminium spelling note. - [Silicon Element](https://ferrumone.com/en/element/silicon): Atomic number 14, symbol Si, atomic mass 28.085, electron configuration [Ne] 3s² 3p², semiconductor uses, allotropes, isotopes, compounds and FAQ. - [Phosphorus Element](https://ferrumone.com/en/element/phosphorus): Atomic number 15, symbol P, atomic mass 30.974, electron configuration [Ne] 3s² 3p³, allotropes, biological role, uses, isotope, compounds and FAQ. - [Sulfur Element](https://ferrumone.com/en/element/sulfur): Atomic number 16, symbol S, atomic mass 32.06, electron configuration [Ne] 3s² 3p⁴, sulfur allotropes, sulfuric acid, uses, isotopes, compounds and FAQ. - [Chlorine Element](https://ferrumone.com/en/element/chlorine): Atomic number 17, symbol Cl, atomic mass 35.45, electron configuration [Ne] 3s² 3p⁵, halogen properties, water disinfection, uses, isotopes and FAQ. - [Argon Element](https://ferrumone.com/en/element/argon): Atomic number 18, symbol Ar, atomic mass 39.948, electron configuration [Ne] 3s² 3p⁶, noble gas properties, atmosphere facts, uses, isotopes and FAQ. - [Potassium Element](https://ferrumone.com/en/element/potassium): Atomic number 19, symbol K, atomic mass 39.098, electron configuration [Ar] 4s¹, alkali metal properties, biological role, uses, isotopes and FAQ. - [Calcium Element](https://ferrumone.com/en/element/calcium): Atomic number 20, symbol Ca, atomic mass 40.078, electron configuration [Ar] 4s², biological role, uses, isotopes, compounds and FAQ. - [Scandium Element](https://ferrumone.com/en/element/scandium): Atomic number 21, symbol Sc, atomic mass 44.956, electron configuration [Ar] 3d¹ 4s², aluminum-scandium alloys, eka-boron history, isotopes and FAQ. - [Titanium Element](https://ferrumone.com/en/element/titanium): Atomic number 22, symbol Ti, atomic mass 47.867, electron configuration [Ar] 3d² 4s², aerospace alloys, implants, titanium dioxide, isotopes and FAQ. - [Vanadium Element](https://ferrumone.com/en/element/vanadium): Atomic number 23, symbol V, atomic mass 50.942, electron configuration [Ar] 3d³ 4s², redox batteries, oxidation states, V₂O₅ catalyst and FAQ. - [Chromium Element](https://ferrumone.com/en/element/chromium): Atomic number 24, symbol Cr, atomic mass 51.996, electron configuration [Ar] 3d⁵ 4s¹, electron configuration exception, stainless steel, chromium(VI) and FAQ. - [Manganese Element](https://ferrumone.com/en/element/manganese): Atomic number 25, symbol Mn, atomic mass 54.938, electron configuration [Ar] 3d⁵ 4s², steelmaking, KMnO₄, photosynthesis and FAQ. - [Iron Element](https://ferrumone.com/en/element/iron): Atomic number 26, symbol Fe, atomic mass 55.845, electron configuration [Ar] 3d⁶ 4s², steel, hemoglobin, rust, isotopes and FAQ. - [Cobalt Element](https://ferrumone.com/en/element/cobalt): Atomic number 27, symbol Co, atomic mass 58.933, electron configuration [Ar] 3d⁷ 4s², vitamin B12, cobalt-60, batteries and FAQ. - [Nickel Element](https://ferrumone.com/en/element/nickel): Atomic number 28, symbol Ni, atomic mass 58.693, electron configuration [Ar] 3d⁸ 4s², stainless steel, nickel allergy, Raney nickel and FAQ. - [Copper Element](https://ferrumone.com/en/element/copper): Atomic number 29, symbol Cu, atomic mass 63.546, electron configuration [Ar] 3d¹⁰ 4s¹, conductivity, bronze, brass, patina and FAQ. - [Zinc Element](https://ferrumone.com/en/element/zinc): Atomic number 30, symbol Zn, atomic mass 65.38, electron configuration [Ar] 3d¹⁰ 4s², galvanizing, zinc oxide, zinc fingers and FAQ. - [Gallium Element](https://ferrumone.com/en/element/gallium): Atomic number 31, symbol Ga, atomic mass 69.723, electron configuration [Ar] 3d¹⁰ 4s² 4p¹, GaN LEDs, GaAs semiconductors, eka-aluminum and FAQ. - [Germanium Element](https://ferrumone.com/en/element/germanium): Atomic number 32, symbol Ge, atomic mass 72.63, electron configuration [Ar] 3d¹⁰ 4s² 4p², infrared optics, fiber optics, semiconductor history and FAQ. - [Arsenic Element](https://ferrumone.com/en/element/arsenic): Atomic number 33, symbol As, atomic mass 74.922, electron configuration [Ar] 3d¹⁰ 4s² 4p³, toxicity, allotropes, GaAs and FAQ. - [Selenium Element](https://ferrumone.com/en/element/selenium): Atomic number 34, symbol Se, atomic mass 78.971, electron configuration [Ar] 3d¹⁰ 4s² 4p⁴, selenocysteine, allotropes, photoconductivity and FAQ. - [Bromine Element](https://ferrumone.com/en/element/bromine): Atomic number 35, symbol Br, atomic mass 79.904, electron configuration [Ar] 3d¹⁰ 4s² 4p⁵, liquid nonmetal, silver bromide photography and FAQ. - [Krypton Element](https://ferrumone.com/en/element/krypton): Atomic number 36, symbol Kr, atomic mass 83.798, electron configuration [Ar] 3d¹⁰ 4s² 4p⁶, noble gas properties, KrF lasers, krypton-85, meter definition and FAQ. - [Rubidium Element](https://ferrumone.com/en/element/rubidium): Atomic number 37, symbol Rb, atomic mass 85.468, electron configuration [Kr] 5s¹, atomic clocks, Rb-Sr dating, Rb-82 PET and FAQ. - [Strontium Element](https://ferrumone.com/en/element/strontium): Atomic number 38, symbol Sr, atomic mass 87.62, electron configuration [Kr] 5s², red fireworks, Sr-90, isotope tracing and FAQ. - [Yttrium Element](https://ferrumone.com/en/element/yttrium): Atomic number 39, symbol Y, atomic mass 88.906, electron configuration [Kr] 4d¹ 5s², YAG lasers, YBCO superconductors, Y-90 and FAQ. - [Zirconium Element](https://ferrumone.com/en/element/zirconium): Atomic number 40, symbol Zr, atomic mass 91.224, electron configuration [Kr] 4d² 5s², nuclear cladding, zirconia, cubic zirconia and FAQ. - [Niobium Element](https://ferrumone.com/en/element/niobium): Atomic number 41, symbol Nb, atomic mass 92.906, electron configuration [Kr] 4d⁴ 5s¹, superconductors, HSLA steel, columbium history and FAQ. - [Molybdenum Element](https://ferrumone.com/en/element/molybdenum): Atomic number 42, symbol Mo, atomic mass 95.95, electron configuration [Kr] 4d⁵ 5s¹, MoS₂, molybdenum cofactor, Mo-99 and FAQ. - [Technetium Element](https://ferrumone.com/en/element/technetium): Atomic number 43, symbol Tc, atomic mass 98, electron configuration [Kr] 4d⁵ 5s², technetium-99m, no stable isotopes and FAQ. - [Ruthenium Element](https://ferrumone.com/en/element/ruthenium): Atomic number 44, symbol Ru, atomic mass 101.07, electron configuration [Kr] 4d⁷ 5s¹, RuO₂ electrodes, catalysts, platinum-group metal and FAQ. - [Rhodium Element](https://ferrumone.com/en/element/rhodium): Atomic number 45, symbol Rh, atomic mass 102.91, electron configuration [Kr] 4d⁸ 5s¹, catalytic converters, rhodium plating, Wilkinson catalyst and FAQ. - [Palladium Element](https://ferrumone.com/en/element/palladium): Atomic number 46, symbol Pd, atomic mass 106.42, electron configuration [Kr] 4d¹⁰, catalytic converters, cross-coupling, hydrogen absorption and FAQ. - [Silver Element](https://ferrumone.com/en/element/silver): Atomic number 47, symbol Ag, atomic mass 107.87, electron configuration [Kr] 4d¹⁰ 5s¹, conductivity, silver bromide photography, Ag symbol and FAQ. - [Cadmium Element](https://ferrumone.com/en/element/cadmium): Atomic number 48, symbol Cd, atomic mass 112.41, electron configuration [Kr] 4d¹⁰ 5s², toxicity, Ni-Cd batteries, CdTe solar cells and FAQ. - [Indium Element](https://ferrumone.com/en/element/indium): Atomic number 49, symbol In, atomic mass 114.82, electron configuration [Kr] 4d¹⁰ 5s² 5p¹, ITO touchscreens, InP semiconductors, CIGS and FAQ. - [Tin Element](https://ferrumone.com/en/element/tin): Atomic number 50, symbol Sn, atomic mass 118.71, electron configuration [Kr] 4d¹⁰ 5s² 5p², allotropes, tin pest, solder, bronze and FAQ. - [Antimony Element](https://ferrumone.com/en/element/antimony): Atomic number 51, symbol Sb, atomic mass 121.76, electron configuration [Kr] 4d¹⁰ 5s² 5p³, flame retardants, stibnite, GeSbTe, allotropes and FAQ. - [Tellurium Element](https://ferrumone.com/en/element/tellurium): Atomic number 52, symbol Te, atomic mass 127.60, electron configuration [Kr] 4d¹⁰ 5s² 5p⁴, CdTe solar cells, Bi₂Te₃ thermoelectrics, tellurium breath and FAQ. - [Iodine Element](https://ferrumone.com/en/element/iodine): Atomic number 53, symbol I, atomic mass 126.90, electron configuration [Kr] 4d¹⁰ 5s² 5p⁵, thyroid hormones, iodized salt, iodine-131, iodine-starch test and FAQ. - [Xenon Element](https://ferrumone.com/en/element/xenon): Atomic number 54, symbol Xe, atomic mass 131.29, electron configuration [Kr] 4d¹⁰ 5s² 5p⁶, noble gas compounds, ion propulsion, xenon-135 and FAQ. - [Cesium Element](https://ferrumone.com/en/element/cesium): Atomic number 55, symbol Cs, atomic mass 132.91, electron configuration [Xe] 6s¹, cesium atomic clock, cesium-137, low melting point and FAQ. - [Barium Element](https://ferrumone.com/en/element/barium): Atomic number 56, symbol Ba, atomic mass 137.33, electron configuration [Xe] 6s², barium sulfate X-ray contrast, green flame, barium titanate and FAQ. - [Lanthanum Element](https://ferrumone.com/en/element/lanthanum): Atomic number 57, symbol La, atomic mass 138.91, electron configuration [Xe] 5d¹ 6s², optical glass, NiMH batteries, lanthanum carbonate and FAQ. - [Cerium Element](https://ferrumone.com/en/element/cerium): Atomic number 58, symbol Ce, atomic mass 140.12, electron configuration [Xe] 4f¹ 5d¹ 6s², cerium oxide polishing, catalytic converter oxygen storage and FAQ. - [Praseodymium Element](https://ferrumone.com/en/element/praseodymium): Atomic number 59, symbol Pr, atomic mass 140.91, electron configuration [Xe] 4f³ 6s², rare earth magnets, yellow pigments, didymium glass and FAQ. - [Neodymium Element](https://ferrumone.com/en/element/neodymium): Atomic number 60, symbol Nd, atomic mass 144.24, electron configuration [Xe] 4f⁴ 6s², Nd-Fe-B magnets, Nd:YAG lasers, rare earth supply chains and FAQ. - [Promethium Element](https://ferrumone.com/en/element/promethium): Atomic number 61, symbol Pm, atomic mass 145, electron configuration [Xe] 4f⁵ 6s², no stable isotopes, promethium-147, beta sources and FAQ. - [Samarium Element](https://ferrumone.com/en/element/samarium): Atomic number 62, symbol Sm, atomic mass 150.36, electron configuration [Xe] 4f⁶ 6s², SmCo magnets, samarium-153 EDTMP, SmI₂ and FAQ. - [Europium Element](https://ferrumone.com/en/element/europium): Atomic number 63, symbol Eu, atomic mass 151.96, electron configuration [Xe] 4f⁷ 6s², red and blue phosphors, euro banknote fluorescence and FAQ. - [Gadolinium Element](https://ferrumone.com/en/element/gadolinium): Atomic number 64, symbol Gd, atomic mass 157.25, electron configuration [Xe] 4f⁷ 5d¹ 6s², MRI contrast, gadolinium-157 neutron absorption and FAQ. - [Terbium Element](https://ferrumone.com/en/element/terbium): Atomic number 65, symbol Tb, atomic mass 158.93, electron configuration [Xe] 4f⁹ 6s², green phosphors, Terfenol-D and FAQ. - [Dysprosium Element](https://ferrumone.com/en/element/dysprosium): Atomic number 66, symbol Dy, atomic mass 162.50, electron configuration [Xe] 4f¹⁰ 6s², EV motor magnets, Terfenol-D, neutron absorbers and FAQ. - [Holmium Element](https://ferrumone.com/en/element/holmium): Atomic number 67, symbol Ho, atomic mass 164.93, electron configuration [Xe] 4f¹¹ 6s², Ho:YAG lasers, holmium-165 and FAQ. - [Erbium Element](https://ferrumone.com/en/element/erbium): Atomic number 68, symbol Er, atomic mass 167.26, electron configuration [Xe] 4f¹² 6s², EDFA fiber amplifiers, Er:YAG lasers, 1550 nm telecom and FAQ. - [Thulium Element](https://ferrumone.com/en/element/thulium): Atomic number 69, symbol Tm, atomic mass 168.93, electron configuration [Xe] 4f¹³ 6s², thulium-170, Tm:YAG surgical lasers and FAQ. - [Ytterbium Element](https://ferrumone.com/en/element/ytterbium): Atomic number 70, symbol Yb, atomic mass 173.04, electron configuration [Xe] 4f¹⁴ 6s², fiber lasers, optical lattice clocks and FAQ. - [Lutetium Element](https://ferrumone.com/en/element/lutetium): Atomic number 71, symbol Lu, atomic mass 174.97, electron configuration [Xe] 4f¹⁴ 5d¹ 6s², Lu-177 targeted radiotherapy, LSO/LYSO PET detector crystals, Lu-Hf dating and FAQ. - [Hafnium Element](https://ferrumone.com/en/element/hafnium): Atomic number 72, symbol Hf, atomic mass 178.49, electron configuration [Xe] 4f¹⁴ 5d² 6s², HfO₂ high-k dielectrics, neutron control rods, hafnium-zirconium similarity and FAQ. - [Tantalum Element](https://ferrumone.com/en/element/tantalum): Atomic number 73, symbol Ta, atomic mass 180.95, electron configuration [Xe] 4f¹⁴ 5d³ 6s², tantalum capacitors, Ta₂O₅ dielectric, biocompatible implants, tantalum-180m and FAQ. - [Tungsten Element](https://ferrumone.com/en/element/tungsten): Atomic number 74, symbol W, atomic mass 183.84, electron configuration [Xe] 4f¹⁴ 5d⁴ 6s², highest melting point, tungsten carbide, wolfram symbol origin and FAQ. - [Rhenium Element](https://ferrumone.com/en/element/rhenium): Atomic number 75, symbol Re, atomic mass 186.21, electron configuration [Xe] 4f¹⁴ 5d⁵ 6s², rhenium superalloys, platinum-rhenium catalysts, Re-Os dating and FAQ. - [Osmium Element](https://ferrumone.com/en/element/osmium): Atomic number 76, symbol Os, atomic mass 190.23, electron configuration [Xe] 4f¹⁴ 5d⁶ 6s², osmium density, osmium tetroxide, Re-Os isotope systems and FAQ. - [Iridium Element](https://ferrumone.com/en/element/iridium): Atomic number 77, symbol Ir, atomic mass 192.22, electron configuration [Xe] 4f¹⁴ 5d⁷ 6s², K-Pg boundary iridium anomaly, iridium spark plugs, iridium-192 and FAQ. - [Platinum Element](https://ferrumone.com/en/element/platinum): Atomic number 78, symbol Pt, atomic mass 195.08, electron configuration [Xe] 4f¹⁴ 5d⁹ 6s¹, catalytic converters, cisplatin, fuel cell catalysts and FAQ. - [Gold Element](https://ferrumone.com/en/element/gold): Atomic number 79, symbol Au, atomic mass 196.97, electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s¹, gold nanoparticles, Au symbol, relativistic color, JWST gold coating and FAQ. - [Mercury Element](https://ferrumone.com/en/element/mercury): Atomic number 80, symbol Hg, atomic mass 200.59, electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s², liquid metal, methylmercury, Minamata disease and FAQ. - [Thallium Element](https://ferrumone.com/en/element/thallium): Atomic number 81, symbol Tl, atomic mass 204.38, electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹, thallium toxicity, Tl-201 SPECT, NaI(Tl) scintillators and FAQ. - [Lead Element](https://ferrumone.com/en/element/lead): Atomic number 82, symbol Pb, atomic mass 207.2, electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p², lead toxicity, lead-acid batteries, radiation shielding, U-Pb dating and FAQ. - [Bismuth Element](https://ferrumone.com/en/element/bismuth): Atomic number 83, symbol Bi, atomic mass 208.98, electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p³, bismuth subsalicylate, Bi₂Te₃ thermoelectrics, bismuth-209 and FAQ. - [Polonium Element](https://ferrumone.com/en/element/polonium): Atomic number 84, symbol Po, atomic mass 209, electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁴, Po-210 alpha emission, static eliminators, Curie discovery and FAQ. - [Astatine Element](https://ferrumone.com/en/element/astatine): Atomic number 85, symbol At, atomic mass 210, electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵, At-211 targeted alpha therapy research, radioactive halogen chemistry and FAQ. - [Radon Element](https://ferrumone.com/en/element/radon): Atomic number 86, symbol Rn, atomic mass 222, electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶, radon-222, indoor radon, lung cancer risk and FAQ. - [Francium Element](https://ferrumone.com/en/element/francium): Atomic number 87, symbol Fr, atomic mass 223, electron configuration [Rn] 7s¹, francium-223, rare radioactive alkali metal, atomic physics and FAQ. - [Radium Element](https://ferrumone.com/en/element/radium): Atomic number 88, symbol Ra, atomic mass 226, electron configuration [Rn] 7s², radium-223 therapy, radium-226, Radium Girls, radon source and FAQ. - [Actinium Element](https://ferrumone.com/en/element/actinium): Atomic number 89, symbol Ac, atomic mass 227, electron configuration [Rn] 6d¹ 7s², actinium-225 targeted alpha therapy, actinium-227 and FAQ. - [Thorium Element](https://ferrumone.com/en/element/thorium): Atomic number 90, symbol Th, atomic mass 232.04, electron configuration [Rn] 6d² 7s², thorium-232, thorium fuel cycle, uranium-233 breeding and FAQ. - [Protactinium Element](https://ferrumone.com/en/element/protactinium): Atomic number 91, symbol Pa, atomic mass 231.04, electron configuration [Rn] 5f² 6d¹ 7s², protactinium-231, Pa-231/Th-230 dating, uranium decay chains and FAQ. - [Uranium Element](https://ferrumone.com/en/element/uranium): Atomic number 92, symbol U, atomic mass 238.03, electron configuration [Rn] 5f³ 6d¹ 7s², uranium-235, uranium-238, nuclear fuel, UF₆ enrichment, U-Pb dating and FAQ. - [Neptunium Element](https://ferrumone.com/en/element/neptunium): Atomic number 93, symbol Np, atomic mass 237, electron configuration [Rn] 5f⁴ 6d¹ 7s², first transuranium element, neptunium-237, plutonium-238 production and FAQ. - [Plutonium Element](https://ferrumone.com/en/element/plutonium): Atomic number 94, symbol Pu, atomic mass 244, electron configuration [Rn] 5f⁶ 7s², plutonium-238 RTGs, plutonium-239, MOX fuel and FAQ. - [Americium Element](https://ferrumone.com/en/element/americium): Atomic number 95, symbol Am, atomic mass 243, electron configuration [Rn] 5f⁷ 7s², americium-241 smoke detectors, industrial gauges and FAQ. - [Curium Element](https://ferrumone.com/en/element/curium): Atomic number 96, symbol Cm, atomic mass 247, electron configuration [Rn] 5f⁷ 6d¹ 7s², curium-244 APXS, Mars rover instruments and FAQ. - [Berkelium Element](https://ferrumone.com/en/element/berkelium): Atomic number 97, symbol Bk, atomic mass 247, electron configuration [Rn] 5f⁹ 7s², berkelium-249, tennessine synthesis and FAQ. - [Californium Element](https://ferrumone.com/en/element/californium): Atomic number 98, symbol Cf, atomic mass 251, electron configuration [Rn] 5f¹⁰ 7s², californium-252 neutron source, reactor startup, NAA and FAQ. - [Einsteinium Element](https://ferrumone.com/en/element/einsteinium): Atomic number 99, symbol Es, atomic mass 252, electron configuration [Rn] 5f¹¹ 7s², Ivy Mike discovery, einsteinium-253, mendelevium synthesis and FAQ. - [Fermium Element](https://ferrumone.com/en/element/fermium): Atomic number 100, symbol Fm, atomic mass 257, electron configuration [Rn] 5f¹² 7s², fermium-257, fermium wall and FAQ. - [Mendelevium Element](https://ferrumone.com/en/element/mendelevium): Atomic number 101, symbol Md, atomic mass 258, electron configuration [Rn] 5f¹³ 7s², mendelevium-258, atom-by-atom synthesis, +2/+3 chemistry and FAQ. - [Nobelium Element](https://ferrumone.com/en/element/nobelium): Atomic number 102, symbol No, atomic mass 259, electron configuration [Rn] 5f¹⁴ 7s², nobelium-259, stable No²⁺ chemistry and FAQ. - [Lawrencium Element](https://ferrumone.com/en/element/lawrencium): Atomic number 103, symbol Lr, atomic mass 262, electron configuration [Rn] 5f¹⁴ 7s² 7p¹, lawrencium ionization energy, last actinide and FAQ. - [Rutherfordium Element](https://ferrumone.com/en/element/rutherfordium): Atomic number 104, symbol Rf, atomic mass 267, electron configuration [Rn] 5f¹⁴ 6d² 7s², rutherfordium chloride, Group 4 transactinide chemistry and FAQ. - [Dubnium Element](https://ferrumone.com/en/element/dubnium): Atomic number 105, symbol Db, atomic mass 268, electron configuration [Rn] 5f¹⁴ 6d³ 7s², dubnium-268, Group 5 chemistry, transfermium naming and FAQ. - [Seaborgium Element](https://ferrumone.com/en/element/seaborgium): Atomic number 106, symbol Sg, atomic mass 271, electron configuration [Rn] 5f¹⁴ 6d⁴ 7s², seaborgium oxychloride, Glenn Seaborg and FAQ. - [Bohrium Element](https://ferrumone.com/en/element/bohrium): Atomic number 107, symbol Bh, atomic mass 270, electron configuration [Rn] 5f¹⁴ 6d⁵ 7s², bohrium oxychloride, rhenium analog chemistry and FAQ. - [Hassium Element](https://ferrumone.com/en/element/hassium): Atomic number 108, symbol Hs, atomic mass 277, electron configuration [Rn] 5f¹⁴ 6d⁶ 7s², hassium tetroxide, osmium tetroxide analog and FAQ. - [Meitnerium Element](https://ferrumone.com/en/element/meitnerium): Atomic number 109, symbol Mt, atomic mass 278, electron configuration [Rn] 5f¹⁴ 6d⁷ 7s², Lise Meitner, predicted iridium-like chemistry and FAQ. - [Darmstadtium Element](https://ferrumone.com/en/element/darmstadtium): Atomic number 110, symbol Ds, atomic mass 281, electron configuration [Rn] 5f¹⁴ 6d⁹ 7s¹, GSI Darmstadt discovery, predicted platinum-like chemistry and FAQ. - [Roentgenium Element](https://ferrumone.com/en/element/roentgenium): Atomic number 111, symbol Rg, atomic mass 282, electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s¹, roentgenium-282, Wilhelm Röntgen, predicted gold-like chemistry and FAQ. - [Copernicium Element](https://ferrumone.com/en/element/copernicium): Atomic number 112, symbol Cn, atomic mass 285, electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s², copernicium-285, relativistic noble-liquid behavior and FAQ. - [Nihonium Element](https://ferrumone.com/en/element/nihonium): Atomic number 113, symbol Nh, atomic mass 286, electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p¹, RIKEN discovery, first element discovered in Asia and FAQ. - [Flerovium Element](https://ferrumone.com/en/element/flerovium): Atomic number 114, symbol Fl, atomic mass 289, electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p², flerovium-289, island of stability and FAQ. - [Moscovium Element](https://ferrumone.com/en/element/moscovium): Atomic number 115, symbol Mc, atomic mass 290, electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p³, moscovium-290, decay chains to nihonium and FAQ. - [Livermorium Element](https://ferrumone.com/en/element/livermorium): Atomic number 116, symbol Lv, atomic mass 293, electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁴, livermorium-293, Lawrence Livermore naming and FAQ. - [Tennessine Element](https://ferrumone.com/en/element/tennessine): Atomic number 117, symbol Ts, atomic mass 294, electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁵, tennessine-294, berkelium-249 target and FAQ. - [Oganesson Element](https://ferrumone.com/en/element/oganesson): Atomic number 118, symbol Og, atomic mass 294, electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁶, oganesson-294, heaviest known element, period 7 completion and FAQ. ### SEO Notes English pages use their own canonical URLs and reciprocal hreflang links with the Turkish periodic table and all 118 Turkish element pages. The English periodic table sitemap is available at `https://ferrumone.com/sitemap-en.xml`. --- ## Element Detail Pages (English) Each of the 118 elements has a dedicated SEO page at `https://ferrumone.com/en/element/{slug}`. Pages are statically generated (SSG). Each includes a hero card (symbol, name, atomic mass, electron configuration), properties table, prev/next navigation and FAQPage JSON-LD when extended content exists. **hreflang:** each English element page links to the Turkish counterpart at `/element/{tr-slug}`. ### Elements 1–59 (Hydrogen–Praseodymium) ### Hydrogen (H) — https://ferrumone.com/en/element/hydrogen Atom no: 1 | Nonmetal | Period 1, Group 1 **Title:** Hydrogen: Atomic Number, Uses and Isotopes **Description:** Hydrogen element guide: atomic number 1, symbol H, atomic mass 1.008, electron configuration 1s¹, uses, isotopes, compounds and key facts. **Keywords:** hydrogen element, hydrogen atomic number, hydrogen electron configuration, hydrogen uses, hydrogen isotopes, hydrogen symbol, water electrolysis hydrogen **Properties:** atomic mass 1.008 u; electron configuration 1s¹; state Gas; electronegativity 2.2 - **History:** Henry Cavendish isolated hydrogen gas in 1766 and described it as inflammable air. Antoine Lavoisier later named it hydrogen, from Greek roots meaning water-former, after showing that water is made from hydrogen and oxygen. - **Isotopes:** Protium, 99.9885%, The most common hydrogen isotope; its nucleus contains one proton and no neutrons.; Deuterium (D), 0.0115%, A stable isotope with one neutron; used in heavy water (D₂O).; Tritium (T), Trace amounts, t½=12.32 years, Radioactive; used in fusion research and tracing applications. - **Compounds:** H₂O (Water), H₂O₂ (Hydrogen Peroxide), HCl (Hydrochloric Acid), NH₃ (Ammonia), CH₄ (Methane) - **Uses:** Fuel cells and clean-energy systems; Ammonia production by the Haber-Bosch process; Hydrogenation of oils and industrial chemicals; Liquid hydrogen rocket fuel; Hydrodesulfurization in petroleum refining - **Biology:** Hydrogen is essential in water and organic molecules. Hydrogen ions are also central to pH, acid-base balance and proton gradients used in cellular energy production. - **Interesting:** Hydrogen accounts for roughly three quarters of the mass of visible matter in the universe. In the Sun, hydrogen nuclei fuse into helium and release the energy that powers sunlight. Hydrogen has the lowest density of all chemical elements. Hydrogen fuel cells produce water as the main exhaust product. - **Study notes:** Hydrogen has atomic number 1, so a neutral hydrogen atom has one proton and one electron. The electron configuration of hydrogen is 1s¹. In water electrolysis, hydrogen gas forms at the cathode while oxygen forms at the anode. Hydrogen can have an oxidation state of +1 in many compounds and -1 in metal hydrides. - **FAQ:** What is the atomic number of hydrogen? → The atomic number of hydrogen is 1. | What is the electron configuration of hydrogen? → Hydrogen has the electron configuration 1s¹. | What are the main isotopes of hydrogen? → The main isotopes are protium, deuterium and tritium. ### Helium (He) — https://ferrumone.com/en/element/helium Atom no: 2 | Noble Gas | Period 1, Group 18 **Title:** Helium: Atomic Number, Uses and Isotopes **Description:** Helium element guide: atomic number 2, symbol He, atomic mass 4.0026, electron configuration 1s², noble gas properties, uses and isotopes. **Keywords:** helium element, helium atomic number, helium electron configuration, helium uses, helium isotopes, noble gas helium, superfluid helium **Properties:** atomic mass 4.0026 u; electron configuration 1s²; state Gas - **History:** Helium was first detected in 1868 as an unknown yellow spectral line in sunlight during a solar eclipse. It was later isolated on Earth from uranium minerals by Sir William Ramsay in 1895. - **Isotopes:** Helium-3, 0.000137%, Rare isotope used in neutron detection and low-temperature research.; Helium-4, 99.99986%, The dominant helium isotope; equivalent to an alpha particle nucleus. - **Compounds:** HeH⁺ (Helium Hydride Ion) - **Uses:** Balloons and airships because it is nonflammable; Liquid helium cooling for MRI superconducting magnets; Heliox breathing mixtures for deep diving and medical use; Leak detection due to its small atomic size; Low-temperature physics and cryogenic research - **Biology:** Helium has no known biological role. Because it is inert, it can be mixed with oxygen for specialized breathing gases used in deep-sea diving. - **Interesting:** Helium has the lowest boiling point of any element. At normal pressure helium does not solidify, even near absolute zero. Helium-4 becomes a superfluid below about 2.17 K, allowing it to flow with nearly zero viscosity. Most helium on Earth is produced by radioactive alpha decay and accumulates in natural gas deposits. Inhaling helium raises voice pitch because sound travels faster in helium than in air. - **Study notes:** Helium is in group 18 and is classified as a noble gas. Its electron configuration is 1s², a full first shell. Helium is chemically inert because removing or sharing its electrons requires very high energy. - **FAQ:** What is the atomic number of helium? → The atomic number of helium is 2. | What is the electron configuration of helium? → Helium has the electron configuration 1s². | Why is helium a noble gas? → Helium has a filled first electron shell, which makes it extremely unreactive. ### Lithium (Li) — https://ferrumone.com/en/element/lithium Atom no: 3 | Alkali Metal | Period 2, Group 1 **Title:** Lithium: Atomic Number, Uses and Isotopes **Description:** Lithium element guide: atomic number 3, symbol Li, atomic mass 6.94, electron configuration [He] 2s¹, alkali metal properties, uses and compounds. **Keywords:** lithium element, lithium atomic number, lithium electron configuration, lithium uses, lithium ion battery, lithium compounds, lithium flame test **Properties:** atomic mass 6.94 u; electron configuration [He] 2s¹; state Solid; electronegativity 0.98 - **History:** Lithium was discovered in 1817 by Johan August Arfwedson while analyzing the mineral petalite. Its name comes from lithos, the Greek word for stone, because it was found in a mineral rather than in plant ash or animal material. - **Isotopes:** Lithium-6, 7.59%, Used in some nuclear applications and tritium production.; Lithium-7, 92.41%, The most abundant lithium isotope. - **Compounds:** LiOH (Lithium Hydroxide), Li₂CO₃ (Lithium Carbonate), LiCl (Lithium Chloride), LiBH₄ (Lithium Borohydride), LiAlH₄ (Lithium Aluminum Hydride) - **Uses:** Rechargeable lithium-ion and lithium-polymer batteries; Lithium carbonate in mood-stabilizing medicine; Aluminum-lithium alloys for lightweight aerospace materials; Heat-resistant glass and ceramics; Lithium hydroxide for carbon dioxide removal systems - **Biology:** Lithium is not an essential nutrient, but lithium carbonate is used as a mood-stabilizing medicine. Lithium compounds must be handled carefully because excessive intake can be toxic. - **Interesting:** Lithium is the least dense metal and can float on water. Lithium gives a crimson-red color in a flame test. During charging and discharging, lithium ions move between the electrodes of a lithium-ion battery. - **Study notes:** Lithium is an alkali metal in group 1 and commonly forms Li⁺. Its electron configuration is [He] 2s¹, so it has one valence electron. Lithium reacts with water to form lithium hydroxide and hydrogen gas, but less vigorously than sodium or potassium. Alkali metal reactivity generally increases down the group: Li < Na < K < Rb < Cs. - **FAQ:** What is the atomic number of lithium? → The atomic number of lithium is 3. | What is the electron configuration of lithium? → Lithium has the electron configuration [He] 2s¹. | Is lithium a metal? → Yes. Lithium is the lightest metal and belongs to the alkali metal group. ### Beryllium (Be) — https://ferrumone.com/en/element/beryllium Atom no: 4 | Alkaline Earth Metal | Period 2, Group 2 **Title:** Beryllium: Atomic Number, Uses and Isotopes **Description:** Beryllium element guide: atomic number 4, symbol Be, atomic mass 9.0122, electron configuration [He] 2s², uses, isotope, toxicity and key facts. **Keywords:** beryllium element, beryllium atomic number, beryllium electron configuration, beryllium uses, beryllium isotope, beryllium toxicity, beryllium amphoteric **Properties:** atomic mass 9.0122 u; electron configuration [He] 2s²; state Solid; electronegativity 1.57 - **History:** Beryllium was identified in beryl and emerald minerals by Louis-Nicolas Vauquelin in 1798. Its name comes from beryl, the mineral family in which it was first recognized. - **Isotopes:** Beryllium-9, 100%, The only stable naturally occurring isotope of beryllium.; Beryllium-10, Trace amounts, t½=1.39 million years, A radioactive isotope used in geological and climate studies. - **Compounds:** BeO (Beryllium Oxide), BeCl₂ (Beryllium Chloride), Be(OH)₂ (Beryllium Hydroxide) - **Uses:** Copper-beryllium alloys for springs, electrical contacts and non-sparking tools; Lightweight aerospace and satellite components; X-ray windows because beryllium is transparent to X-rays; Neutron reflectors and moderators in nuclear technology; Precision instruments that need stiffness with low mass - **Biology:** Beryllium has no known biological role. Beryllium dust and many beryllium compounds are hazardous because inhalation can cause serious lung disease. - **Interesting:** Beryllium is one of the lightest metals. Beryllium has a high melting point compared with many other light metals. Beryllium occurs in gemstones such as emerald and aquamarine as part of beryl minerals. Beryllium oxide has unusually high thermal conductivity for a ceramic material. Beryllium safety is important because fine particles can be harmful when inhaled. - **Study notes:** Beryllium has atomic number 4 and belongs to group 2. Its electron configuration is [He] 2s². Beryllium hydroxide is amphoteric, reacting with both acids and strong bases. Beryllium commonly forms Be²⁺, but its small ion size gives its compounds unusual covalent character. - **FAQ:** What is the atomic number of beryllium? → The atomic number of beryllium is 4. | What is the electron configuration of beryllium? → Beryllium has the electron configuration [He] 2s². | Is beryllium toxic? → Yes. Beryllium dust and many beryllium compounds are toxic, especially if inhaled. ### Boron (B) — https://ferrumone.com/en/element/boron Atom no: 5 | Metalloid | Period 2, Group 13 **Title:** Boron: Atomic Number, Uses and Isotopes **Description:** Boron element guide: atomic number 5, symbol B, atomic mass 10.81, electron configuration [He] 2s² 2p¹, allotropes, uses, isotopes and compounds. **Keywords:** boron element, boron atomic number, boron electron configuration, boron uses, boron isotopes, boron compounds, boron allotropes, boron lewis acid **Properties:** atomic mass 10.81 u; electron configuration [He] 2s² 2p¹; state Solid; electronegativity 2.04 - **History:** Boron was isolated in 1808 by Joseph Louis Gay-Lussac and Louis Jacques Thenard in France and independently by Humphry Davy in England. Its name is connected to borax, a boron-containing mineral. - **Isotopes:** Boron-10, About 19.9%, Strong neutron absorber used in nuclear and radiation-shielding applications.; Boron-11, About 80.1%, The most abundant stable isotope of boron. - **Allotropes:** Amorphous Boron (Dark brown powder form used commercially; less ordered than crystalline boron.); Alpha-Rhombohedral Boron (Crystalline form built from B₁₂ icosahedral units.); Beta-Rhombohedral Boron (Complex crystalline form often described as the most stable form at ordinary conditions.); Gamma-Boron (High-pressure boron allotrope with a very hard orthorhombic structure.) - **Compounds:** H₃BO₃ (Boric Acid), Na₂B₄O₇·10H₂O (Borax), BF₃ (Boron Trifluoride), B₄C (Boron Carbide), BN (Boron Nitride) - **Uses:** Borosilicate glass such as laboratory glassware and heat-resistant cookware; Borax and boric acid in detergents, antiseptics and glazes; Boron carbide for abrasives and armor materials; Boron nitride for high-performance ceramics and lubricants; Boron-10 for neutron absorption, shielding and reactor control - **Biology:** Boron is essential for plant cell walls and plant growth. In humans it is not classified as an essential nutrient, but small amounts are commonly obtained from fruits, vegetables and nuts. - **Interesting:** Boron trifluoride is electron deficient: boron has only six electrons around it, so BF₃ acts as a Lewis acid. Boron can produce a green color in some flame and pyrotechnic applications. Boron-10 is especially useful because it absorbs neutrons effectively. Borosilicate glass is valued because it resists thermal shock. - **Study notes:** Boron has atomic number 5 and is classified as a metalloid. Its electron configuration is [He] 2s² 2p¹. Boron sits in group 13 and has three valence electrons. Boron compounds such as BF₃ and BCl₃ are classic electron-deficient Lewis acids. - **FAQ:** What is the atomic number of boron? → The atomic number of boron is 5. | What is the electron configuration of boron? → Boron has the electron configuration [He] 2s² 2p¹. | Is boron a metal? → No. Boron is classified as a metalloid. ### Carbon (C) — https://ferrumone.com/en/element/carbon Atom no: 6 | Nonmetal | Period 2, Group 14 **Title:** Carbon: Atomic Number, Uses and Isotopes **Description:** Carbon element guide: atomic number 6, symbol C, atomic mass 12.011, electron configuration [He] 2s² 2p², allotropes, uses and isotopes. **Keywords:** carbon element, carbon atomic number, carbon electron configuration, carbon uses, carbon isotopes, carbon allotropes, carbon monoxide toxic **Properties:** atomic mass 12.011 u; electron configuration [He] 2s² 2p²; state Solid; electronegativity 2.55 - **History:** Carbon has been known since ancient times in forms such as charcoal, soot, graphite and diamond. Antoine Lavoisier later helped establish carbon as a chemical element. - **Isotopes:** Carbon-12, About 98.93%, The standard isotope used as the basis for atomic mass.; Carbon-13, About 1.07%, Stable isotope used in NMR and isotope tracing.; Carbon-14, Trace amounts, t½=5,730 years, Radioactive isotope used in radiocarbon dating. - **Allotropes:** Diamond (Each carbon atom bonds to four others in a strong sp³ network; diamond is extremely hard and electrically insulating.); Graphite (Layered sp² carbon network; layers slide easily and the material conducts electricity.); Graphene (A single atomic layer of graphite with exceptional strength and electrical properties.); Fullerenes (Molecular carbon cages such as C₆₀, shaped like hollow spheres or related structures.); Carbon Nanotubes (Cylindrical graphene-like structures studied for strong, lightweight and conductive materials.) - **Compounds:** CO₂ (Carbon Dioxide), CO (Carbon Monoxide), CH₄ (Methane), CaCO₃ (Calcium Carbonate), C₆H₁₂O₆ (Glucose) - **Uses:** Graphite in pencils, electrodes, lubricants and furnace linings; Diamond for cutting, drilling and abrasive tools; Carbon fiber for lightweight sports, aerospace and structural materials; Coal, oil and natural gas as carbon-rich energy sources; Graphene, fullerenes and carbon nanotubes in advanced materials research - **Biology:** Carbon is essential to life. It forms the backbone of organic molecules such as carbohydrates, lipids, proteins, nucleic acids and many biomolecules involved in metabolism. - **Interesting:** Diamond and graphite are both made of carbon but have very different properties. Carbon can form long chains and rings, which is why organic chemistry is so large. Carbon-14 dating is used to estimate the age of once-living materials. Graphene is a single layer of carbon atoms arranged in a hexagonal network and is studied for advanced electronics and materials. - **Study notes:** Carbon has atomic number 6 and belongs to group 14. Its electron configuration is [He] 2s² 2p². Carbon has four valence electrons and commonly forms four covalent bonds. - **FAQ:** What is the atomic number of carbon? → The atomic number of carbon is 6. | What is the electron configuration of carbon? → Carbon has the electron configuration [He] 2s² 2p². | What are the main allotropes of carbon? → Important carbon allotropes include diamond, graphite, graphene, fullerenes and amorphous carbon. ### Nitrogen (N) — https://ferrumone.com/en/element/nitrogen Atom no: 7 | Nonmetal | Period 2, Group 15 **Title:** Nitrogen: Atomic Number, Uses and Isotopes **Description:** Nitrogen element guide: atomic number 7, symbol N, atomic mass 14.007, electron configuration [He] 2s² 2p³, uses, isotopes and compounds. **Keywords:** nitrogen element, nitrogen atomic number, nitrogen electron configuration, nitrogen uses, nitrogen isotopes, nitrogen gas, nitrogen fixation, haber bosch process **Properties:** atomic mass 14.007 u; electron configuration [He] 2s² 2p³; state Gas; electronegativity 3.04 - **History:** Nitrogen was identified by Daniel Rutherford in 1772 when he studied air that no longer supported combustion or life. Its name is linked to nitre-forming compounds. - **Isotopes:** Nitrogen-14, About 99.63%, The dominant stable isotope of nitrogen.; Nitrogen-15, About 0.37%, Stable isotope used in tracing and NMR studies. - **Compounds:** NH₃ (Ammonia), HNO₃ (Nitric Acid), NO₂ (Nitrogen Dioxide), N₂O (Nitrous Oxide) - **Uses:** Ammonia production by the Haber process for fertilizers; Inert atmospheres for food packaging and electronics manufacturing; Liquid nitrogen for cryogenic cooling and rapid freezing; Production of nitric acid, nylon, dyes and explosives; Steel processing and controlled-atmosphere heat treatment - **Biology:** Nitrogen is essential to living organisms because it is found in amino acids, proteins, DNA and RNA. Plants obtain usable nitrogen through nitrogen fixation and nitrogen-containing nutrients. - **Interesting:** Most atmospheric nitrogen exists as N₂, a very stable molecule. The N≡N triple bond is extremely strong, which is why atmospheric nitrogen must be fixed before most organisms can use it. The Haber-Bosch process is one of the most important industrial reactions because it supplies ammonia for fertilizers. Nitrogen fixation converts atmospheric nitrogen into forms living organisms can use. Liquid nitrogen boils at a very low temperature and is widely used for cooling. - **Study notes:** Nitrogen has atomic number 7 and belongs to group 15. Its electron configuration is [He] 2s² 2p³. Nitrogen has five valence electrons and often forms three covalent bonds. Nitrogen oxidation states range from -3 in ammonia to +5 in nitric acid. - **FAQ:** What is the atomic number of nitrogen? → The atomic number of nitrogen is 7. | What is the electron configuration of nitrogen? → Nitrogen has the electron configuration [He] 2s² 2p³. | How much nitrogen is in the atmosphere? → Nitrogen makes up about 78% of Earth’s atmosphere by volume. ### Oxygen (O) — https://ferrumone.com/en/element/oxygen Atom no: 8 | Nonmetal | Period 2, Group 16 **Title:** Oxygen: Atomic Number, Uses and Isotopes **Description:** Oxygen element guide: atomic number 8, symbol O, atomic mass 15.999, electron configuration [He] 2s² 2p⁴, allotropes, uses, isotopes and compounds. **Keywords:** oxygen element, oxygen atomic number, oxygen electron configuration, oxygen uses, oxygen isotopes, oxygen gas, oxygen allotropes, oxygen paramagnetic, oxygen oxidation states **Properties:** atomic mass 15.999 u; electron configuration [He] 2s² 2p⁴; state Gas; electronegativity 3.44 - **History:** Oxygen was discovered independently by Carl Wilhelm Scheele and Joseph Priestley in the 1770s. Antoine Lavoisier later explained its role in combustion and named it oxygen. - **Isotopes:** Oxygen-16, About 99.76%, The most abundant stable isotope of oxygen.; Oxygen-17, About 0.04%, Stable isotope used in specialized spectroscopy and isotope studies.; Oxygen-18, About 0.20%, Stable isotope used in isotope tracing, climate studies and enriched water. - **Allotropes:** Dioxygen (O₂) (The common atmospheric form of oxygen; it supports respiration and combustion and is paramagnetic.); Ozone (O₃) (Reactive oxygen allotrope that protects Earth in the stratosphere but acts as a pollutant near ground level.) - **Compounds:** H₂O (Water), CO₂ (Carbon Dioxide), H₂O₂ (Hydrogen Peroxide), SiO₂ (Silicon Dioxide) - **Uses:** Steelmaking and metal refining; Medical oxygen and breathing support; Oxy-acetylene welding and metal cutting; Production of chemicals such as hydrogen peroxide and nitric acid; Wastewater and industrial effluent treatment - **Biology:** Oxygen is essential for aerobic respiration in humans and many other organisms. It is also a major component of water, carbohydrates, fats, proteins and many minerals. - **Interesting:** Liquid oxygen is pale blue. O₂ is paramagnetic because it has two unpaired electrons in molecular orbitals. Oxygen is the most abundant element in Earth’s crust by mass. Ozone is a form of oxygen with three oxygen atoms per molecule. Stratospheric ozone absorbs much of the Sun’s harmful UV-B radiation. - **Study notes:** Oxygen has atomic number 8 and belongs to group 16. Its electron configuration is [He] 2s² 2p⁴. Oxygen has six valence electrons and commonly forms O²⁻ in ionic compounds. Oxygen usually has oxidation state -2, but it is -1 in peroxides and positive in compounds with fluorine. - **FAQ:** What is the atomic number of oxygen? → The atomic number of oxygen is 8. | What is the electron configuration of oxygen? → Oxygen has the electron configuration [He] 2s² 2p⁴. | How much oxygen is in the atmosphere? → Oxygen makes up about 21% of Earth’s atmosphere by volume. ### Fluorine (F) — https://ferrumone.com/en/element/fluorine Atom no: 9 | Halogen | Period 2, Group 17 **Title:** Fluorine: Atomic Number, Uses and Isotopes **Description:** Fluorine element guide: atomic number 9, symbol F, atomic mass 18.998, electron configuration [He] 2s² 2p⁵, uses, isotope and compounds. **Keywords:** fluorine element, fluorine atomic number, fluorine electron configuration, fluorine uses, fluorine isotope, most electronegative element, hydrofluoric acid glass etching, fluorine vs fluoride **Properties:** atomic mass 18.998 u; electron configuration [He] 2s² 2p⁵; state Gas; electronegativity 3.98 - **History:** Fluorine was isolated by Henri Moissan in 1886 after many difficult and dangerous attempts by earlier chemists. Its name is related to fluorspar, a mineral containing calcium fluoride. - **Isotopes:** Fluorine-19, 100%, The only stable naturally occurring isotope of fluorine.; Fluorine-18, Synthetic, t½=About 110 minutes, Radioactive isotope used in PET imaging. - **Compounds:** HF (Hydrogen Fluoride), NaF (Sodium Fluoride), CaF₂ (Calcium Fluoride), SF₆ (Sulfur Hexafluoride), PTFE (Polytetrafluoroethylene), UF₆ (Uranium Hexafluoride) - **Uses:** Fluoride compounds in toothpaste and dental health applications; PTFE and other fluoropolymers used in non-stick and chemical-resistant materials; Uranium hexafluoride for uranium enrichment; Hydrofluoric acid for glass etching and industrial chemistry; Fluorine-18 radiotracers for PET medical imaging - **Biology:** Elemental fluorine has no biological role and is highly toxic. Fluoride ions in controlled amounts help protect tooth enamel, while excessive fluoride exposure can be harmful. - **Interesting:** Fluorine is the most electronegative element. Fluorine reacts with many substances very vigorously. Hydrofluoric acid is a weak acid by dissociation, but it is highly dangerous because fluoride can penetrate tissue and bind calcium ions. Fluoride and fluorine are not the same: fluoride is the ion F⁻, while fluorine is the element. - **Study notes:** Fluorine has atomic number 9 and belongs to group 17. Its electron configuration is [He] 2s² 2p⁵. Fluorine has seven valence electrons and commonly forms F⁻. - **FAQ:** What is the atomic number of fluorine? → The atomic number of fluorine is 9. | What is the electron configuration of fluorine? → Fluorine has the electron configuration [He] 2s² 2p⁵. | Why is fluorine important? → Fluorine is important in fluoride dental chemistry, fluoropolymers, uranium hexafluoride, hydrofluoric acid and PET imaging isotopes. ### Neon (Ne) — https://ferrumone.com/en/element/neon Atom no: 10 | Noble Gas | Period 2, Group 18 **Title:** Neon: Atomic Number, Uses and Isotopes **Description:** Neon element guide: atomic number 10, symbol Ne, atomic mass 20.180, electron configuration [He] 2s² 2p⁶, noble gas properties, uses and isotopes. **Keywords:** neon element, neon atomic number, neon electron configuration, neon uses, neon isotopes, noble gas neon, neon signs **Properties:** atomic mass 20.18 u; electron configuration [He] 2s² 2p⁶; state Gas - **History:** Neon was discovered in 1898 by William Ramsay and Morris Travers while studying the fractionated components of liquid air. Its name comes from the Greek word neos, meaning new. - **Isotopes:** Neon-20, About 90.48%, The most abundant stable isotope of neon.; Neon-21, About 0.27%, Stable isotope used in isotope studies.; Neon-22, About 9.25%, Stable isotope of neon. - **Compounds:** — (No Stable Neutral Compound) - **Uses:** Neon signs and advertising displays; High-voltage indicators and switching equipment; Helium-neon lasers and other lighting applications; Lightning arresters; Liquid neon as a cryogenic refrigerant - **Biology:** Neon has no known biological role. It is chemically inert and is not used by living organisms. - **Interesting:** Neon glows reddish-orange in vacuum discharge tubes. Neon is one of the noble gases and has very low chemical reactivity. Neon makes up only about 18 parts per million of Earth’s atmosphere. Neon was historically important in early evidence for isotopes. - **Study notes:** Neon has atomic number 10 and belongs to group 18. Its electron configuration is [He] 2s² 2p⁶. Neon has a full second electron shell, which explains its noble gas behavior. - **FAQ:** What is the atomic number of neon? → The atomic number of neon is 10. | What is the electron configuration of neon? → Neon has the electron configuration [He] 2s² 2p⁶. | Why is neon a noble gas? → Neon has a full outer electron shell, so it is very stable and chemically inert. ### Sodium (Na) — https://ferrumone.com/en/element/sodium Atom no: 11 | Alkali Metal | Period 3, Group 1 **Title:** Sodium: Atomic Number, Uses and Isotopes **Description:** Sodium element guide: atomic number 11, symbol Na, atomic mass 22.990, electron configuration [Ne] 3s¹, uses, isotope, compounds and key facts. **Keywords:** sodium element, sodium atomic number, sodium electron configuration, sodium uses, sodium isotope, sodium compounds, sodium flame test, brine electrolysis **Properties:** atomic mass 22.99 u; electron configuration [Ne] 3s¹; state Solid; electronegativity 0.93 - **History:** Sodium was isolated by Humphry Davy in 1807 through electrolysis of caustic soda. Its chemical symbol, Na, comes from natrium, a Latin-derived name linked to sodium compounds. - **Isotopes:** Sodium-23, 100%, The only stable naturally occurring isotope of sodium.; Sodium-24, Synthetic, t½=About 15 hours, Radioactive isotope used as a tracer in scientific and medical contexts. - **Compounds:** NaCl (Sodium Chloride), NaHCO₃ (Sodium Bicarbonate), Na₂CO₃ (Sodium Carbonate), NaOH (Sodium Hydroxide) - **Uses:** Sodium chloride as table salt and road de-icing salt; Sodium carbonate for glass production, detergents and water softening; Sodium bicarbonate in baking, antacids and cleaning products; Metallic sodium as a reagent and heat-transfer material in specialized systems; Sodium vapor lamps and industrial sodium compounds - **Biology:** Sodium is essential in animals and humans. Sodium ions help regulate fluid balance, nerve impulses and muscle function, although excessive sodium intake is associated with health risks. - **Interesting:** Sodium is stored under oil because it reacts with air and moisture. Sodium reacts with water to form sodium hydroxide and hydrogen gas. The yellow color of many street lamps comes from excited sodium atoms, especially the strong sodium D lines near 589 nm. - **Study notes:** Sodium has atomic number 11 and belongs to group 1. Its electron configuration is [Ne] 3s¹. Sodium commonly loses one electron to form Na⁺. In brine electrolysis, chloride is oxidized at the anode to chlorine gas while hydrogen forms at the cathode. - **FAQ:** What is the atomic number of sodium? → The atomic number of sodium is 11. | What is the electron configuration of sodium? → Sodium has the electron configuration [Ne] 3s¹. | Why is sodium reactive? → Sodium has one outer electron that it can lose easily, which makes it a reactive alkali metal. ### Magnesium (Mg) — https://ferrumone.com/en/element/magnesium Atom no: 12 | Alkaline Earth Metal | Period 3, Group 2 **Title:** Magnesium: Atomic Number, Uses and Isotopes **Description:** Magnesium element guide: atomic number 12, symbol Mg, atomic mass 24.305, electron configuration [Ne] 3s², uses, isotopes and compounds. **Keywords:** magnesium element, magnesium atomic number, magnesium electron configuration, magnesium uses, magnesium isotopes, magnesium compounds, magnesium burns water, magnesium chlorophyll **Properties:** atomic mass 24.305 u; electron configuration [Ne] 3s²; state Solid; electronegativity 1.31 - **History:** Joseph Black distinguished magnesia from lime in 1755, and Humphry Davy later isolated magnesium metal. The name is linked to Magnesia, a region in Greece. - **Isotopes:** Magnesium-24, About 79.0%, The most abundant stable isotope of magnesium.; Magnesium-25, About 10.0%, Stable isotope used in isotope and NMR studies.; Magnesium-26, About 11.0%, Stable isotope used in geochemical and isotope studies. - **Compounds:** MgO (Magnesium Oxide), Mg(OH)₂ (Magnesium Hydroxide), MgSO₄·7H₂O (Magnesium Sulfate), MgCl₂ (Magnesium Chloride) - **Uses:** Lightweight alloys for aircraft, cars, tools and electronic devices; Flares, fireworks and sparklers because burning magnesium gives a bright white light; Magnesium oxide for heat-resistant bricks and furnace linings; Magnesium hydroxide and magnesium sulfate in medical and household uses; Grignard reagents in organic chemistry - **Biology:** Magnesium is essential for life. It is the central atom in chlorophyll and is required for many enzymes, energy metabolism and normal muscle and nerve function. - **Interesting:** Magnesium burns with an intense white flame. Burning magnesium should not be extinguished with water or carbon dioxide because it can keep reacting at high temperature. Magnesium is one of the lightest structural metals. The human body contains roughly 25 g of magnesium, much of it in bones and inside cells. Plants need magnesium because chlorophyll contains magnesium at its center. - **Study notes:** Magnesium has atomic number 12 and belongs to group 2. Its electron configuration is [Ne] 3s². Magnesium commonly forms Mg²⁺ by losing two outer electrons. Magnesium is less reactive with cold water than calcium but reacts more readily with steam. - **FAQ:** What is the atomic number of magnesium? → The atomic number of magnesium is 12. | What is the electron configuration of magnesium? → Magnesium has the electron configuration [Ne] 3s². | Why is magnesium important in biology? → Magnesium is essential in chlorophyll, enzyme function, energy metabolism and normal muscle and nerve activity. ### Aluminum (Al) — https://ferrumone.com/en/element/aluminum Atom no: 13 | Post-Transition Metal | Period 3, Group 13 **Title:** Aluminum: Atomic Number, Uses and Isotopes **Description:** Aluminum element guide: atomic number 13, symbol Al, atomic mass 26.982, electron configuration [Ne] 3s² 3p¹, uses, isotope and compounds. **Keywords:** aluminum element, aluminum atomic number, aluminum electron configuration, aluminum uses, aluminum isotope, aluminium element, hall heroult process, aluminum amphoteric, thermite reaction **Properties:** atomic mass 26.982 u; electron configuration [Ne] 3s² 3p¹; state Solid; electronegativity 1.61 - **History:** Aluminum was first isolated in an impure form by Hans Christian Ørsted in 1825. Its name comes from alum, and the element is also spelled aluminium in many countries. - **Isotopes:** Aluminum-27, 100%, The only stable naturally occurring isotope of aluminum.; Aluminum-26, Trace amounts, t½=About 717,000 years, Radioactive isotope used in cosmochemistry and dating studies. - **Compounds:** Al₂O₃ (Aluminum Oxide), AlCl₃ (Aluminum Chloride), Al(OH)₃ (Aluminum Hydroxide), Al₂(SO₄)₃ (Aluminum Sulfate), Na₃AlF₆ (Cryolite) - **Uses:** Aircraft, vehicles and transportation structures because of low density; Cans, foil, packaging and kitchen utensils; Window frames, building materials and architectural panels; Electrical transmission lines and heat exchangers; Thermite reactions, where aluminum reduces iron oxide to molten iron; Alloys with copper, magnesium, manganese, silicon and other metals - **Biology:** Aluminum has no known essential biological role. Most aluminum exposure comes from food, water and materials, and aluminum compounds are handled carefully in industrial settings. - **Interesting:** Aluminum forms a thin oxide layer that helps protect it from corrosion. Aluminum is the most abundant metal in Earth’s crust. The Hall-Héroult process made aluminum much cheaper by producing it through electrolysis of alumina dissolved in molten cryolite. Recycling aluminum saves most of the energy required to produce new aluminum from ore. Aluminum is spelled aluminium in British and IUPAC-style usage, but aluminum is common in US English. - **Study notes:** Aluminum has atomic number 13 and belongs to group 13. Its electron configuration is [Ne] 3s² 3p¹. Aluminum hydroxide is amphoteric, meaning it can react with both acids and strong bases. Aluminum commonly forms Al³⁺ in ionic compounds. - **FAQ:** What is the atomic number of aluminum? → The atomic number of aluminum is 13. | What is the electron configuration of aluminum? → Aluminum has the electron configuration [Ne] 3s² 3p¹. | Is aluminum the same as aluminium? → Yes. Aluminum and aluminium refer to the same element; aluminum is common in US English, while aluminium is common in many other countries. ### Silicon (Si) — https://ferrumone.com/en/element/silicon Atom no: 14 | Metalloid | Period 3, Group 14 **Title:** Silicon: Atomic Number, Uses and Isotopes **Description:** Silicon element guide: atomic number 14, symbol Si, atomic mass 28.085, electron configuration [Ne] 3s² 3p², allotropes, uses, isotopes and compounds. **Keywords:** silicon element, silicon atomic number, silicon electron configuration, silicon uses, silicon isotopes, silicon semiconductor, silicon allotropes, silicon vs silicone, silicon dioxide hydrofluoric acid **Properties:** atomic mass 28.085 u; electron configuration [Ne] 3s² 3p²; state Solid; electronegativity 1.9 - **History:** Silicon was isolated by Jöns Jacob Berzelius in 1824. Its name comes from Latin words related to flint, reflecting its connection with silica-rich minerals. - **Isotopes:** Silicon-28, About 92.2%, The most abundant stable isotope of silicon.; Silicon-29, About 4.7%, Stable isotope used in NMR and isotope studies.; Silicon-30, About 3.1%, Stable isotope of silicon. - **Allotropes:** Crystalline Silicon (Diamond-cubic semiconductor form used in microchips and most solar cells.); Amorphous Silicon (Non-crystalline silicon network used in thin-film solar cells and display electronics.); Silicene (Graphene-like one-atom-thick silicon sheet studied for future nanoelectronics.) - **Compounds:** SiO₂ (Silicon Dioxide), SiC (Silicon Carbide), SiH₄ (Silane), SiCl₄ (Silicon Tetrachloride), Na₂SiO₃ (Sodium Silicate) - **Uses:** Semiconductors, computer chips and solar cells using highly purified silicon; Glass, concrete, cement and ceramics from silica-rich materials; Silicones used as sealants, lubricants, rubbers and medical materials; Aluminum-silicon and ferrosilicon alloys; Silicon carbide abrasives and high-performance ceramics - **Biology:** Silicon is essential for some plants and is important in many natural silica structures. Its exact role in animals is less clear, although silicon is present in small amounts in the body. - **Interesting:** Silicon is the basis of modern microelectronics. Pure crystalline silicon has a blue-grey metallic sheen. Silicon Valley is named after semiconductor silicon, but silicon the element and silicone polymers are different materials. Crystalline silicon has a band gap of about 1.12 eV, which is important for solar cells and electronics. Silica minerals make up a large part of rocks, sand and many construction materials. - **Study notes:** Silicon has atomic number 14 and belongs to group 14. Its electron configuration is [Ne] 3s² 3p². Silicon is a metalloid and commonly forms four covalent bonds. Silicon dioxide is a covalent network solid and is attacked by hydrofluoric acid more readily than by most common acids. - **FAQ:** What is the atomic number of silicon? → The atomic number of silicon is 14. | What is the electron configuration of silicon? → Silicon has the electron configuration [Ne] 3s² 3p². | Why is silicon important in electronics? → Silicon is a semiconductor, so purified and doped silicon can control electrical current in computer chips and solar cells. ### Phosphorus (P) — https://ferrumone.com/en/element/phosphorus Atom no: 15 | Nonmetal | Period 3, Group 15 **Title:** Phosphorus: Atomic Number, Uses and Isotopes **Description:** Phosphorus element guide: atomic number 15, symbol P, atomic mass 30.974, electron configuration [Ne] 3s² 3p³, allotropes, uses, isotope and compounds. **Keywords:** phosphorus element, phosphorus atomic number, phosphorus electron configuration, phosphorus uses, phosphorus isotope, phosphorus compounds, phosphorus allotropes, white phosphorus red phosphorus, phosphorus dna atp **Properties:** atomic mass 30.974 u; electron configuration [Ne] 3s² 3p³; state Solid; electronegativity 2.19 - **History:** Phosphorus was discovered by Hennig Brand in 1669 while experimenting with urine. Its name comes from Greek roots meaning light-bringer, because white phosphorus glows in the dark. - **Isotopes:** Phosphorus-31, 100%, The only stable naturally occurring isotope of phosphorus.; Phosphorus-32, Synthetic, t½=About 14.3 days, Radioactive isotope used in biological and medical research. - **Allotropes:** White Phosphorus (P₄) (Highly reactive and toxic molecular allotrope that can ignite in air and glows faintly in the dark.); Red Phosphorus (More stable polymeric form used on safety match striking surfaces.); Black Phosphorus (Layered and more stable allotrope studied as a semiconductor and two-dimensional material.); Violet Phosphorus (Crystalline Hittorf phosphorus with a complex structure and low reactivity.) - **Compounds:** H₃PO₄ (Phosphoric Acid), Ca₃(PO₄)₂ (Calcium Phosphate), P₄O₁₀ (Phosphorus Pentoxide), PCl₃ (Phosphorus Trichloride), PCl₅ (Phosphorus Pentachloride), Na₃PO₄ (Sodium Phosphate) - **Uses:** Phosphate fertilizers for agriculture; Red phosphorus on safety match striking surfaces; Phosphates in some detergents, special glasses and ceramics; Phosphorus compounds in steel production and chemical manufacturing; White phosphorus in flares, smoke devices and specialized military applications - **Biology:** Phosphorus is essential for all living organisms. It forms part of DNA, RNA, ATP and phospholipids, and much of the phosphorus in the human body is stored as calcium phosphate in bones and teeth. - **Interesting:** White phosphorus glows faintly in the dark and is highly dangerous. Red phosphorus is much safer than white phosphorus and is used in safety matches. Black phosphorus has a layered structure and is studied as a two-dimensional semiconductor material. The negative charge of DNA comes from phosphate groups in its sugar-phosphate backbone. ATP, the main energy currency of cells, contains phosphate groups. - **Study notes:** Phosphorus has atomic number 15 and belongs to group 15. Its electron configuration is [Ne] 3s² 3p³. Phosphorus has five valence electrons and can form several oxidation states. PCl₅ is a classic example used to discuss expanded valence around a third-period central atom. - **FAQ:** What is the atomic number of phosphorus? → The atomic number of phosphorus is 15. | What is the electron configuration of phosphorus? → Phosphorus has the electron configuration [Ne] 3s² 3p³. | Why is phosphorus important for life? → Phosphorus is found in DNA, RNA, ATP, phospholipids, bones and teeth. ### Sulfur (S) — https://ferrumone.com/en/element/sulfur Atom no: 16 | Nonmetal | Period 3, Group 16 **Title:** Sulfur: Atomic Number, Uses and Isotopes **Description:** Sulfur element guide: atomic number 16, symbol S, atomic mass 32.06, electron configuration [Ne] 3s² 3p⁴, allotropes, uses, isotopes and compounds. **Keywords:** sulfur element, sulfur atomic number, sulfur electron configuration, sulfur uses, sulfur isotopes, sulfur compounds, sulfur allotropes, contact process sulfuric acid, sulfur dioxide acid rain **Properties:** atomic mass 32.06 u; electron configuration [Ne] 3s² 3p⁴; state Solid; electronegativity 2.58 - **History:** Sulfur has been known since ancient times because it occurs naturally near volcanoes and hot springs. The name is related to old Latin and Sanskrit roots, and sulfur became industrially important through sulfuric acid chemistry. - **Isotopes:** Sulfur-32, About 95.0%, The most abundant stable isotope of sulfur.; Sulfur-33, About 0.75%, Stable isotope used in isotope and NMR studies.; Sulfur-34, About 4.25%, Stable isotope important in geochemical sulfur cycle studies.; Sulfur-36, About 0.01%, Rare stable isotope of sulfur. - **Allotropes:** Rhombic Sulfur (alpha-S) (Most stable room-temperature form, made of S₈ crown-shaped ring molecules.); Monoclinic Sulfur (beta-S) (S₈-based crystalline form stable over a higher temperature range before converting back on cooling.); Plastic Sulfur (Rubbery amorphous sulfur formed by rapidly cooling molten sulfur; it slowly crystallizes back to ordinary sulfur.) - **Compounds:** H₂SO₄ (Sulfuric Acid), SO₂ (Sulfur Dioxide), H₂S (Hydrogen Sulfide), FeS₂ (Iron Disulfide (Pyrite)), CuSO₄ (Copper(II) Sulfate), CaSO₄ (Calcium Sulfate) - **Uses:** Sulfuric acid production for fertilizers and industrial chemistry; Vulcanization of rubber to improve strength and elasticity; Fungicides and agricultural chemicals; Black powder, matches and some pyrotechnic mixtures; Petroleum refining and sulfur compound production - **Biology:** Sulfur is essential for life. It is found in the amino acids cysteine and methionine, in some vitamins and coenzymes, and in disulfide bonds that help stabilize protein structures. - **Interesting:** Elemental sulfur commonly exists as S₈ ring-shaped molecules. Sulfur is often recognized by its bright yellow solid form. Sulfur dioxide can dissolve in rainwater and contribute to acid rain chemistry. Disulfide bonds help give hair and many proteins their shape and strength. - **Study notes:** Sulfur has atomic number 16 and belongs to group 16, the chalcogens. Its electron configuration is [Ne] 3s² 3p⁴. Sulfur commonly appears in oxidation states such as -2, +4 and +6. In the contact process, SO₂ is oxidized to SO₃ before sulfuric acid is produced. - **FAQ:** What is the atomic number of sulfur? → The atomic number of sulfur is 16. | What is the electron configuration of sulfur? → Sulfur has the electron configuration [Ne] 3s² 3p⁴. | Why is sulfur important for life? → Sulfur is found in amino acids, proteins, vitamins, coenzymes and disulfide bonds. ### Chlorine (Cl) — https://ferrumone.com/en/element/chlorine Atom no: 17 | Halogen | Period 3, Group 17 **Title:** Chlorine: Atomic Number, Uses and Isotopes **Description:** Chlorine element guide: atomic number 17, symbol Cl, atomic mass 35.45, electron configuration [Ne] 3s² 3p⁵, uses, isotopes and compounds. **Keywords:** chlorine element, chlorine atomic number, chlorine electron configuration, chlorine uses, chlorine isotopes, chlorine halogen, chlorine water disinfection, chlorine pvc, chlorine ozone layer **Properties:** atomic mass 35.45 u; electron configuration [Ne] 3s² 3p⁵; state Gas; electronegativity 3.16 - **History:** Chlorine was discovered by Carl Wilhelm Scheele in 1774. Humphry Davy later recognized it as an element, and its name comes from the Greek word chloros, meaning greenish yellow. - **Isotopes:** Chlorine-35, About 75.8%, The most abundant stable isotope of chlorine.; Chlorine-37, About 24.2%, Stable isotope that creates the characteristic M+2 mass spectrum pattern with chlorine compounds.; Chlorine-36, Trace amounts, t½=About 301,000 years, Radioactive isotope used in environmental and geological studies. - **Compounds:** NaCl (Sodium Chloride), HCl (Hydrochloric Acid), NaClO (Sodium Hypochlorite), PVC (Polyvinyl Chloride), CaCl₂ (Calcium Chloride) - **Uses:** Disinfection of drinking water and swimming pools; Production of PVC plastics and many chlorinated chemicals; Household and industrial bleach through hypochlorite compounds; Manufacture of pharmaceuticals, solvents, paints and polymers; Paper and textile bleaching in controlled industrial processes; Chemical synthesis as an oxidizing and chlorinating agent - **Biology:** Chlorine is essential in the body as chloride ions, which help maintain fluid balance, nerve function and stomach acid. Chlorine gas itself is toxic and must be handled with strict safety controls. - **Interesting:** Chlorine gas is yellow-green and has a sharp, choking smell. Chloride ions are common in seawater and in ordinary table salt. The two main chlorine isotopes make chlorine-containing molecules easy to recognize in mass spectra. Chlorination of drinking water was one of the major public-health advances of the twentieth century. Chlorine atoms released from some CFCs can catalytically destroy ozone in the stratosphere. - **Study notes:** Chlorine has atomic number 17 and belongs to group 17, the halogens. Its electron configuration is [Ne] 3s² 3p⁵. Chlorine commonly forms Cl⁻ by gaining one electron. Chlorine reacts with water to form hydrochloric acid and hypochlorous acid, a key disinfecting species. - **FAQ:** What is the atomic number of chlorine? → The atomic number of chlorine is 17. | What is the electron configuration of chlorine? → Chlorine has the electron configuration [Ne] 3s² 3p⁵. | Is chlorine a halogen? → Yes. Chlorine is a group 17 halogen. ### Argon (Ar) — https://ferrumone.com/en/element/argon Atom no: 18 | Noble Gas | Period 3, Group 18 **Title:** Argon: Atomic Number, Uses and Isotopes **Description:** Argon element guide: atomic number 18, symbol Ar, atomic mass 39.948, electron configuration [Ne] 3s² 3p⁶, noble gas uses and isotopes. **Keywords:** argon element, argon atomic number, argon electron configuration, argon uses, argon isotopes, noble gas argon, argon atmosphere abundance, potassium argon dating **Properties:** atomic mass 39.95 u; electron configuration [Ne] 3s² 3p⁶; state Gas - **History:** Argon was discovered in 1894 by Lord Rayleigh and William Ramsay while studying nitrogen from air. Its name comes from the Greek argos, meaning inactive, because argon is very unreactive. - **Isotopes:** Argon-36, About 0.34%, Stable isotope of argon.; Argon-38, About 0.06%, Rare stable isotope of argon.; Argon-40, About 99.60%, The dominant isotope in Earth’s atmosphere, largely produced by potassium-40 decay. - **Compounds:** ArF* (Argon Fluoride Excimer), HArF (Argon Fluorohydride) - **Uses:** Inert shielding gas for welding and metal cutting; Filling incandescent and fluorescent lamps; Insulating gas in double-glazed windows; Protective atmosphere for producing reactive metals and semiconductor crystals; Argon lasers and plasma applications - **Biology:** Argon has no known biological role. It is generally chemically inert and non-toxic, but like other inert gases it can displace oxygen in confined spaces. - **Interesting:** Argon is the third most abundant gas in Earth’s atmosphere after nitrogen and oxygen. Most atmospheric argon is argon-40 from the decay of potassium-40 in rocks. Potassium-argon dating uses the buildup of argon-40 to estimate the age of rocks and minerals. The name argon reflects its low chemical reactivity. - **Study notes:** Argon has atomic number 18 and belongs to group 18, the noble gases. Its electron configuration is [Ne] 3s² 3p⁶, giving argon a full valence shell. Argon is monatomic under ordinary conditions because it is very inert. Argon is the most abundant noble gas in Earth’s atmosphere. - **FAQ:** What is the atomic number of argon? → The atomic number of argon is 18. | What is the electron configuration of argon? → Argon has the electron configuration [Ne] 3s² 3p⁶. | Is argon a noble gas? → Yes. Argon is a group 18 noble gas. ### Potassium (K) — https://ferrumone.com/en/element/potassium Atom no: 19 | Alkali Metal | Period 4, Group 1 **Title:** Potassium: Atomic Number, Uses and Isotopes **Description:** Potassium element guide: atomic number 19, symbol K, atomic mass 39.098, electron configuration [Ar] 4s¹, uses, isotopes and compounds. **Keywords:** potassium element, potassium atomic number, potassium electron configuration, potassium uses, potassium isotopes, potassium symbol K, potassium flame test, sodium potassium pump, potassium 40 dating **Properties:** atomic mass 39.098 u; electron configuration [Ar] 4s¹; state Solid; electronegativity 0.82 - **History:** Potassium was isolated by Humphry Davy in 1807 through electrolysis of potash. The English name comes from potash, while the symbol K comes from kalium, a Latinized name linked to alkali. - **Isotopes:** Potassium-39, About 93.3%, The most abundant stable isotope of potassium.; Potassium-40, About 0.012%, t½=About 1.25 billion years, Naturally radioactive isotope used in potassium-argon dating.; Potassium-41, About 6.7%, Stable isotope of potassium. - **Compounds:** KCl (Potassium Chloride), KOH (Potassium Hydroxide), KNO₃ (Potassium Nitrate), K₂CO₃ (Potassium Carbonate), KMnO₄ (Potassium Permanganate) - **Uses:** Potassium fertilizers for plant growth; Potassium nitrate in fertilizers, food preservation and black powder formulations; Potassium carbonate in glass manufacturing; Potassium hydroxide in liquid soaps, detergents and alkaline batteries; Potassium chloride in medicine, electrolyte solutions and salt substitutes; Potassium compounds in chemical synthesis and industrial processes - **Biology:** Potassium is essential for life as K⁺ ions. It helps regulate fluid balance, nerve impulses, muscle contraction and heart rhythm, and it is a major electrolyte inside cells. - **Interesting:** Potassium metal is soft enough to cut with a knife and tarnishes quickly in air. Potassium is less dense than sodium, an exception to the simple “density increases down the alkali metals” idea. Potassium gives a lilac flame color in flame tests. The radioactive isotope potassium-40 contributes a small part of natural background radiation and decays to both argon-40 and calcium-40. - **Study notes:** Potassium has atomic number 19 and belongs to group 1, the alkali metals. Its electron configuration is [Ar] 4s¹. Potassium commonly forms K⁺ by losing one valence electron. The sodium-potassium pump moves Na⁺ and K⁺ ions across cell membranes and is essential for nerve and muscle function. - **FAQ:** What is the atomic number of potassium? → The atomic number of potassium is 19. | What is the electron configuration of potassium? → Potassium has the electron configuration [Ar] 4s¹. | Why is the symbol for potassium K? → The symbol K comes from kalium, a Latinized name related to alkali. ### Calcium (Ca) — https://ferrumone.com/en/element/calcium Atom no: 20 | Alkaline Earth Metal | Period 4, Group 2 **Title:** Calcium: Atomic Number, Uses and Isotopes **Description:** Calcium element guide: atomic number 20, symbol Ca, atomic mass 40.078, electron configuration [Ar] 4s², uses, isotopes and compounds. **Keywords:** calcium element, calcium atomic number, calcium electron configuration, calcium uses, calcium isotopes, calcium compounds, water hardness calcium, calcium flame test, calcium carbonate limestone caves **Properties:** atomic mass 40.078 u; electron configuration [Ar] 4s²; state Solid; electronegativity 1 - **History:** Calcium was isolated by Humphry Davy in 1808 by electrolysis. Its name comes from the Latin calx, meaning lime, because calcium compounds occur in limestone and lime. - **Isotopes:** Calcium-40, About 96.9%, The most abundant stable isotope of calcium.; Calcium-42, About 0.65%, Stable isotope of calcium.; Calcium-44, About 2.1%, Stable isotope used in isotope studies.; Calcium-48, About 0.19%, t½=About 4.4 x 10¹⁹ years, Very long-lived double-beta-decay isotope used in nuclear science. - **Compounds:** CaCO₃ (Calcium Carbonate), CaO (Calcium Oxide), Ca(OH)₂ (Calcium Hydroxide), CaSO₄ (Calcium Sulfate), CaF₂ (Calcium Fluoride), Ca₃(PO₄)₂ (Calcium Phosphate) - **Uses:** Limestone and cement production for construction; Quicklime and slaked lime for cement, steelmaking, soil treatment and water treatment; Calcium carbide for acetylene production; Gypsum for plaster, wallboard and casts; Calcium metal as a reducing agent and alloying additive; Calcium chloride for de-icing, drying and dust control - **Biology:** Calcium is essential for living organisms. In humans it is the main mineral in bones and teeth, and Ca²⁺ ions are important in muscle contraction, blood clotting, nerve signaling and cell regulation. - **Interesting:** Calcium is the most abundant metal in the human body. Bones and teeth store most of the body’s calcium as calcium phosphate minerals. The calcium carbonate equilibrium with carbon dioxide and water explains limestone caves, stalactites and stalagmites. Calcium gives a brick-red to orange-red color in flame tests. Calcium compounds are major ingredients in limestone caves, cement and plaster. - **Study notes:** Calcium has atomic number 20 and belongs to group 2, the alkaline earth metals. Its electron configuration is [Ar] 4s². Calcium commonly forms Ca²⁺ by losing two valence electrons. Water hardness is mainly caused by dissolved Ca²⁺ and Mg²⁺ ions. - **FAQ:** What is the atomic number of calcium? → The atomic number of calcium is 20. | What is the electron configuration of calcium? → Calcium has the electron configuration [Ar] 4s². | Why is calcium important for the body? → Calcium is needed for bones, teeth, muscle contraction, blood clotting, nerve signaling and cell regulation. ### Scandium (Sc) — https://ferrumone.com/en/element/scandium Atom no: 21 | Transition Metal | Period 4, Group 3 **Title:** Scandium: Atomic Number, Uses and Isotopes **Description:** Scandium element guide: atomic number 21, symbol Sc, atomic mass 44.956, electron configuration [Ar] 3d¹ 4s², uses, isotopes and compounds. **Keywords:** scandium element, scandium atomic number, scandium electron configuration, scandium uses, scandium isotopes, aluminum scandium alloy, scandium iodide lamps, eka boron scandium **Properties:** atomic mass 44.956 u; electron configuration [Ar] 3d¹ 4s²; state Solid; electronegativity 1.36 - **History:** Scandium was discovered in 1879 by Lars Fredrik Nilson while analyzing rare minerals from Scandinavia. Its properties closely matched Mendeleev’s predicted element eka-boron, helping confirm the predictive power of the periodic table. - **Isotopes:** Scandium-45, 100%, The only stable naturally occurring isotope of scandium.; Scandium-46, Synthetic, t½=About 83.8 days, Radioactive isotope used as a tracer in industrial studies. - **Compounds:** Sc₂O₃ (Scandium Oxide), ScCl₃ (Scandium Chloride), ScI₃ (Scandium Iodide), ScF₃ (Scandium Fluoride) - **Uses:** Aluminum-scandium alloys for lightweight, strong aerospace and sports equipment; Scandium iodide in metal halide lamps to improve bright white light quality; Scandium oxide in specialized ceramics and optical coatings; Scandia-stabilized zirconia electrolytes in solid oxide fuel cells; Scandium-46 radioactive tracer work in industrial flow and leak studies - **Biology:** Scandium has no known essential biological role in humans. Trace amounts can occur in some organisms, but scandium is not considered a required nutrient. - **Interesting:** Scandium was one of the classic confirmations of Mendeleev’s periodic table predictions. Although scandium is not extremely rare in Earth’s crust, it is difficult and expensive to extract in concentrated form. Small scandium additions can significantly strengthen aluminum alloys. Sc³⁺ has an empty d shell, so many scandium compounds are colorless compared with typical transition metal ions. - **Study notes:** Scandium has atomic number 21 and starts the 3d transition metal series in period 4. Its electron configuration is [Ar] 3d¹ 4s². The most common oxidation state is +3. Scandium is often discussed with Mendeleev’s eka-boron prediction because its oxide and properties matched the forecast closely. - **FAQ:** What is the atomic number of scandium? → The atomic number of scandium is 21. | What is the electron configuration of scandium? → Scandium has the electron configuration [Ar] 3d¹ 4s². | What is scandium used for? → Scandium is used in aluminum-scandium alloys, high-intensity lamps, specialized ceramics, optical coatings and solid oxide fuel cell materials. ### Titanium (Ti) — https://ferrumone.com/en/element/titanium Atom no: 22 | Transition Metal | Period 4, Group 4 **Title:** Titanium: Atomic Number, Uses and Isotopes **Description:** Titanium element guide: atomic number 22, symbol Ti, atomic mass 47.867, electron configuration [Ar] 3d² 4s², uses, isotopes and compounds. **Keywords:** titanium element, titanium atomic number, titanium electron configuration, titanium uses, titanium isotopes, titanium dioxide uses, titanium implants, kroll process titanium, Ti-6Al-4V titanium alloy **Properties:** atomic mass 47.867 u; electron configuration [Ar] 3d² 4s²; state Solid; electronegativity 1.54 - **History:** Titanium was first identified by William Gregor in 1791 and later named by Martin Heinrich Klaproth after the Titans of Greek mythology. Industrial titanium production became practical after the Kroll process was developed in the 20th century. - **Isotopes:** Titanium-46, About 8.25%, Stable isotope of titanium.; Titanium-47, About 7.44%, Stable isotope of titanium.; Titanium-48, About 73.7%, The most abundant stable isotope of titanium.; Titanium-49, About 5.41%, Stable isotope of titanium.; Titanium-50, About 5.18%, Stable isotope of titanium. - **Compounds:** TiO₂ (Titanium Dioxide), TiCl₄ (Titanium Tetrachloride), TiN (Titanium Nitride), TiC (Titanium Carbide), BaTiO₃ (Barium Titanate) - **Uses:** Aerospace alloys for aircraft, spacecraft and high-performance parts; Medical and dental implants because titanium is strong and biocompatible; Titanium dioxide as a white pigment in paints, plastics, paper and sunscreens; Marine and chemical equipment where corrosion resistance is important; Titanium nitride and titanium carbide hard coatings for cutting tools - **Biology:** Titanium has no known essential biological role, but it is highly biocompatible. Its stable oxide surface helps titanium implants integrate well with bone and tissue. - **Interesting:** Titanium has one of the best strength-to-weight ratios among structural metals. Titanium resists seawater corrosion because a protective TiO₂ film forms on its surface. TiO₂ is one of the most important white pigments in the world. Ti-6Al-4V is the best-known titanium alloy and is widely used in aerospace and medical applications. The Kroll process reduces TiCl₄ with magnesium under controlled conditions to make titanium metal. - **Study notes:** Titanium has atomic number 22 and belongs to group 4. Its electron configuration is [Ar] 3d² 4s². The most common oxidation state is +4, as in TiO₂ and TiCl₄. Titanium’s biocompatibility is linked to the stable oxide film on its surface. - **FAQ:** What is the atomic number of titanium? → The atomic number of titanium is 22. | What is the electron configuration of titanium? → Titanium has the electron configuration [Ar] 3d² 4s². | What is titanium used for? → Titanium is used in aerospace alloys, medical implants, marine equipment, sports equipment, pigments and hard coatings. ### Vanadium (V) — https://ferrumone.com/en/element/vanadium Atom no: 23 | Transition Metal | Period 4, Group 5 **Title:** Vanadium: Atomic Number, Uses and Isotopes **Description:** Vanadium element guide: atomic number 23, symbol V, atomic mass 50.942, electron configuration [Ar] 3d³ 4s², uses, isotopes and compounds. **Keywords:** vanadium element, vanadium atomic number, vanadium electron configuration, vanadium uses, vanadium isotopes, vanadium redox battery, vanadium oxidation states, vanadium pentoxide catalyst **Properties:** atomic mass 50.942 u; electron configuration [Ar] 3d³ 4s²; state Solid; electronegativity 1.63 - **History:** Vanadium was first discovered by Andrés Manuel del Río in 1801, but the discovery was initially dismissed. Nils Gabriel Sefström rediscovered it in 1830 and named it after Vanadis, a Norse goddess associated with beauty, because vanadium compounds can show vivid colors. - **Isotopes:** Vanadium-51, About 99.75%, The dominant naturally occurring isotope of vanadium.; Vanadium-50, About 0.25%, t½=About 1.4 x 10¹⁷ years, Extremely long-lived radioactive isotope. - **Compounds:** V₂O₅ (Vanadium Pentoxide), VO₂ (Vanadium Dioxide), VOSO₄ (Vanadyl Sulfate), VCl₃ (Vanadium(III) Chloride), NH₄VO₃ (Ammonium Metavanadate) - **Uses:** Ferrovanadium for strong, tough steels and tool steels; Vanadium pentoxide catalyst in the contact process for sulfuric acid production; Vanadium redox flow batteries for large-scale energy storage; Titanium-aluminum-vanadium alloys such as Ti-6Al-4V; Vanadium dioxide smart coatings and thermochromic materials - **Biology:** Vanadium has no confirmed essential role in humans. Some marine organisms concentrate vanadium, and vanadium compounds are studied for biological and metabolic effects. - **Interesting:** Vanadium ions change color with oxidation state: +2 violet, +3 green, +4 blue and +5 yellow. The contact process uses V₂O₅ to catalyze oxidation of SO₂ to SO₃ before sulfuric acid is produced. Vanadium redox flow batteries store energy in liquid electrolytes rather than solid electrodes. Small amounts of vanadium can make steel much stronger and more fatigue-resistant. - **Study notes:** Vanadium has atomic number 23 and belongs to group 5. Its electron configuration is [Ar] 3d³ 4s². Common oxidation states include +2, +3, +4 and +5. The wide oxidation-state range explains vanadium’s colorful ions, catalytic behavior and redox battery chemistry. - **FAQ:** What is the atomic number of vanadium? → The atomic number of vanadium is 23. | What is the electron configuration of vanadium? → Vanadium has the electron configuration [Ar] 3d³ 4s². | What is vanadium used for? → Vanadium is used in strong steels, titanium alloys, sulfuric acid catalysts, redox flow batteries and smart coating research. ### Chromium (Cr) — https://ferrumone.com/en/element/chromium Atom no: 24 | Transition Metal | Period 4, Group 6 **Title:** Chromium: Atomic Number, Uses and Isotopes **Description:** Chromium element guide: atomic number 24, symbol Cr, atomic mass 51.996, electron configuration [Ar] 3d⁵ 4s¹, uses, isotopes and compounds. **Keywords:** chromium element, chromium atomic number, chromium electron configuration, chromium uses, chromium isotopes, chromium electron configuration exception, stainless steel chromium, chromium 6 toxicity **Properties:** atomic mass 51.996 u; electron configuration [Ar] 3d⁵ 4s¹; state Solid; electronegativity 1.66 - **History:** Chromium was discovered by Louis-Nicolas Vauquelin in 1797 in the mineral crocoite. Its name comes from the Greek chroma, meaning color, because chromium compounds produce many bright colors. - **Isotopes:** Chromium-52, About 83.8%, The most abundant stable isotope of chromium.; Chromium-53, About 9.5%, Stable isotope used in isotope and NMR studies.; Chromium-50, About 4.35%, Stable isotope of chromium.; Chromium-54, About 2.36%, Stable isotope of chromium. - **Compounds:** Cr₂O₃ (Chromium(III) Oxide), CrO₃ (Chromium Trioxide), K₂Cr₂O₇ (Potassium Dichromate), K₂CrO₄ (Potassium Chromate), PbCrO₄ (Lead Chromate) - **Uses:** Stainless steel, where chromium forms a protective Cr₂O₃ passive film; Chrome plating for shiny, corrosion-resistant surfaces; Chromium pigments such as chrome green and historical chrome yellow; Refractory chromite materials for high-temperature furnaces; Strong oxidizing reagents such as dichromates in analytical and industrial chemistry - **Biology:** Chromium(III) has been discussed in connection with glucose metabolism, but its essential role in humans remains debated. Hexavalent chromium, chromium(VI), is toxic and carcinogenic, so oxidation state is crucial when discussing chromium safety. - **Interesting:** Chromium’s name comes from color, and chromium compounds can be green, blue, yellow, orange or red. Stainless steel resists rust because chromium forms a thin self-healing oxide film. Chromium has the important electron configuration exception [Ar] 3d⁵ 4s¹. Ruby and emerald colors can both involve chromium ions in different crystal environments. - **Study notes:** Chromium has atomic number 24 and belongs to group 6. Its electron configuration is [Ar] 3d⁵ 4s¹, not [Ar] 3d⁴ 4s². Common oxidation states include +2, +3 and +6. Chromium(VI) compounds are much more hazardous than many chromium(III) compounds, so oxidation state matters. - **FAQ:** What is the atomic number of chromium? → The atomic number of chromium is 24. | What is the electron configuration of chromium? → Chromium has the electron configuration [Ar] 3d⁵ 4s¹. | Why is chromium an electron configuration exception? → Chromium places one 4s electron into the 3d subshell because the half-filled 3d⁵ arrangement is especially stable. ### Manganese (Mn) — https://ferrumone.com/en/element/manganese Atom no: 25 | Transition Metal | Period 4, Group 7 **Title:** Manganese: Atomic Number, Uses and Isotopes **Description:** Manganese element guide: atomic number 25, symbol Mn, atomic mass 54.938, electron configuration [Ar] 3d⁵ 4s², uses, isotopes and compounds. **Keywords:** manganese element, manganese atomic number, manganese electron configuration, manganese uses, manganese isotopes, manganese oxidation states, potassium permanganate, potassium permanganate acidic neutral basic products, manganese dioxide battery **Properties:** atomic mass 54.938 u; electron configuration [Ar] 3d⁵ 4s²; state Solid; electronegativity 1.55 - **History:** Manganese was isolated by Johan Gottlieb Gahn in 1774 from pyrolusite, a manganese dioxide mineral. The name is related to Magnesia, a historical region also connected with the names magnesium and magnetite. - **Isotopes:** Manganese-55, 100%, The only stable naturally occurring isotope of manganese.; Manganese-54, Synthetic / trace cosmogenic, t½=About 312 days, Radioactive isotope used in tracer and environmental studies. - **Compounds:** MnO₂ (Manganese Dioxide), KMnO₄ (Potassium Permanganate), MnSO₄ (Manganese Sulfate), MnO (Manganese(II) Oxide), Mn₂O₇ (Manganese(VII) Oxide) - **Uses:** Steelmaking, where manganese improves hardness, toughness and sulfur removal; Manganese dioxide cathode material in zinc-carbon and alkaline batteries; Potassium permanganate as a strong oxidizing agent; Glass decolorizing and ceramic color applications; Fertilizers and animal feed supplements in controlled amounts - **Biology:** Manganese is an essential trace element. It is a cofactor in enzymes such as manganese superoxide dismutase, and a manganese-calcium cluster in photosystem II helps split water during photosynthesis. - **Interesting:** Manganese-55 is the only stable isotope of manganese. Potassium permanganate changes reduction products depending on whether the solution is acidic, neutral or basic. The oxygen released by photosynthesis comes from water splitting at a manganese-calcium cluster. Very high occupational manganese exposure can harm the nervous system, so manganese is essential but dose-sensitive. - **Study notes:** Manganese has atomic number 25 and belongs to group 7. Its electron configuration is [Ar] 3d⁵ 4s². Manganese shows many oxidation states, commonly +2, +4 and +7. KMnO₄ contains manganese in the +7 oxidation state and is a classic strong oxidizer. Permanganate reduction products depend on pH: acidic solutions often give Mn²⁺, neutral conditions can give MnO₂, and strongly basic conditions can give manganate, MnO₄²⁻. - **FAQ:** What is the atomic number of manganese? → The atomic number of manganese is 25. | What is the electron configuration of manganese? → Manganese has the electron configuration [Ar] 3d⁵ 4s². | What is manganese used for? → Manganese is used in steelmaking, batteries, potassium permanganate, glass chemistry, fertilizers and animal nutrition. ### Iron (Fe) — https://ferrumone.com/en/element/iron Atom no: 26 | Transition Metal | Period 4, Group 8 **Title:** Iron: Atomic Number, Uses and Isotopes **Description:** Iron element guide: atomic number 26, symbol Fe, atomic mass 55.845, electron configuration [Ar] 3d⁶ 4s², uses, isotopes and compounds. **Keywords:** iron element, iron atomic number, iron electron configuration, iron uses, iron isotopes, iron symbol Fe, iron in hemoglobin, rust chemical reaction, steel vs cast iron **Properties:** atomic mass 55.845 u; electron configuration [Ar] 3d⁶ 4s²; state Solid; electronegativity 1.83 - **History:** Iron has been used since ancient times, with widespread use marking the Iron Age. The symbol Fe comes from the Latin word ferrum, and iron-nickel meteorites provided some of the earliest metallic iron used by humans. - **Isotopes:** Iron-56, About 91.75%, The most abundant stable isotope of iron.; Iron-54, About 5.85%, Stable isotope of iron.; Iron-57, About 2.12%, Stable isotope used in Mössbauer spectroscopy.; Iron-58, About 0.28%, Stable isotope of iron. - **Compounds:** Fe₂O₃ (Iron(III) Oxide), Fe₃O₄ (Iron(II,III) Oxide), FeSO₄ (Iron(II) Sulfate), FeCl₃ (Iron(III) Chloride), Fe(CO)₅ (Iron Pentacarbonyl) - **Uses:** Steel production for buildings, vehicles, machines and infrastructure; Cast iron and wrought iron for tools, pipes, cookware and historical structures; Iron catalysts in the Haber-Bosch process for ammonia production; Magnetic cores, electromagnets and transformers; Iron supplements and fortified foods for treating or preventing iron deficiency - **Biology:** Iron is essential for oxygen transport and cellular energy. Fe²⁺ in heme helps hemoglobin carry oxygen, while iron-sulfur clusters and cytochromes participate in electron transport and redox chemistry. - **Interesting:** Iron is the main metal in Earth’s core and one of the most important metals in human civilization. Rusting is an electrochemical corrosion process involving iron, oxygen and water. Hemoglobin depends on iron to bind and transport oxygen in the blood. Iron-57 Mössbauer spectroscopy can reveal oxidation state and bonding environment in minerals and catalysts. - **Study notes:** Iron has atomic number 26 and belongs to group 8. Its electron configuration is [Ar] 3d⁶ 4s². The most common oxidation states are +2 and +3. Steel is mostly iron with controlled carbon and alloying elements; cast iron has much higher carbon content than most steels. - **FAQ:** What is the atomic number of iron? → The atomic number of iron is 26. | What is the electron configuration of iron? → Iron has the electron configuration [Ar] 3d⁶ 4s². | Why is the symbol for iron Fe? → The symbol Fe comes from ferrum, the Latin word for iron. ### Cobalt (Co) — https://ferrumone.com/en/element/cobalt Atom no: 27 | Transition Metal | Period 4, Group 9 **Title:** Cobalt: Atomic Number, Uses and Isotopes **Description:** Cobalt element guide: atomic number 27, symbol Co, atomic mass 58.933, electron configuration [Ar] 3d⁷ 4s², uses, isotopes and compounds. **Keywords:** cobalt element, cobalt atomic number, cobalt electron configuration, cobalt uses, cobalt isotopes, cobalt vitamin B12, cobalt 60, cobalt chloride humidity indicator, lithium cobalt oxide battery **Properties:** atomic mass 58.933 u; electron configuration [Ar] 3d⁷ 4s²; state Solid; electronegativity 1.88 - **History:** Cobalt was identified as a distinct metal by Georg Brandt in the 18th century. Its name comes from the German Kobold, a mining goblin, because cobalt ores confused miners and often released harmful arsenic fumes. - **Isotopes:** Cobalt-59, 100%, The only stable naturally occurring isotope of cobalt.; Cobalt-60, Synthetic, t½=About 5.27 years, Radioactive gamma emitter used in medicine, sterilization and radiography. - **Compounds:** CoO (Cobalt(II) Oxide), CoCl₂ (Cobalt(II) Chloride), CoAl₂O₄ (Cobalt Aluminate), LiCoO₂ (Lithium Cobalt Oxide), Co₂(CO)₈ (Dicobalt Octacarbonyl) - **Uses:** Lithium cobalt oxide cathodes in rechargeable lithium-ion batteries; Superalloys for jet engines and high-temperature turbine parts; Cobalt blue pigments for glass, ceramics and art materials; Cobalt-60 gamma sources for radiotherapy, sterilization and industrial radiography; Permanent magnets such as samarium-cobalt and Alnico alloys - **Biology:** Cobalt is essential as the central metal in vitamin B12, also called cobalamin. Vitamin B12 is needed for red blood cell formation, DNA synthesis and nervous system function. - **Interesting:** Vitamin B12 is the best-known cobalt-containing biomolecule. Cobalt blue pigments have been valued in glass and ceramics for centuries. Anhydrous cobalt(II) chloride is blue, while hydrated cobalt chloride is pink, so it has been used as a humidity indicator. Cobalt-60 emits strong gamma rays and must be handled with strict radiation controls. Cobalt demand is linked to rechargeable batteries and high-performance alloys. - **Study notes:** Cobalt has atomic number 27 and belongs to group 9. Its electron configuration is [Ar] 3d⁷ 4s². Common oxidation states include +2 and +3. Cobalt in vitamin B12 is an example of a transition metal with a direct biological role. - **FAQ:** What is the atomic number of cobalt? → The atomic number of cobalt is 27. | What is the electron configuration of cobalt? → Cobalt has the electron configuration [Ar] 3d⁷ 4s². | What is cobalt used for? → Cobalt is used in lithium-ion batteries, superalloys, blue pigments, magnets, radiotherapy sources and sterilization. ### Nickel (Ni) — https://ferrumone.com/en/element/nickel Atom no: 28 | Transition Metal | Period 4, Group 10 **Title:** Nickel: Atomic Number, Uses and Isotopes **Description:** Nickel element guide: atomic number 28, symbol Ni, atomic mass 58.693, electron configuration [Ar] 3d⁸ 4s², uses, isotopes and compounds. **Keywords:** nickel element, nickel atomic number, nickel electron configuration, nickel uses, nickel isotopes, nickel allergy, raney nickel catalyst, mond process nickel, stainless steel nickel **Properties:** atomic mass 58.693 u; electron configuration [Ar] 3d⁸ 4s²; state Solid; electronegativity 1.91 - **History:** Nickel was isolated by Axel Fredrik Cronstedt in 1751 from the mineral niccolite. Its name comes from kupfernickel, a miner’s term for an ore that looked like copper ore but did not yield copper. - **Isotopes:** Nickel-58, About 68.1%, The most abundant stable isotope of nickel.; Nickel-60, About 26.2%, Stable isotope of nickel.; Nickel-61, About 1.14%, Stable isotope used in NMR studies.; Nickel-62, About 3.63%, Stable isotope with extremely high binding energy per nucleon.; Nickel-64, About 0.93%, Stable isotope of nickel. - **Compounds:** NiO (Nickel(II) Oxide), NiCl₂ (Nickel(II) Chloride), NiSO₄ (Nickel Sulfate), Ni(CO)₄ (Nickel Tetracarbonyl), Ni(OH)₂ (Nickel(II) Hydroxide) - **Uses:** Stainless steels and corrosion-resistant alloys; Nickel superalloys such as Inconel for jet engines and high-temperature equipment; Electroplating for protective and decorative coatings; Rechargeable batteries including nickel-metal hydride and nickel-cadmium systems; Raney nickel catalyst for hydrogenation reactions - **Biology:** Nickel is essential for some microorganisms and plants in enzymes such as urease and hydrogenase. Its essential role in humans is unclear, and nickel is a common cause of allergic contact dermatitis. - **Interesting:** Nickel is ferromagnetic at room temperature, along with iron and cobalt. The Mond process uses volatile nickel tetracarbonyl to purify nickel, but Ni(CO)₄ is extremely toxic. Raney nickel is a porous catalyst widely used in organic hydrogenation. Nickel contact allergy is one of the most common metal allergies worldwide. - **Study notes:** Nickel has atomic number 28 and belongs to group 10. Its electron configuration is [Ar] 3d⁸ 4s². The most common oxidation state is +2. Nickel improves toughness and corrosion resistance in stainless steels and superalloys. - **FAQ:** What is the atomic number of nickel? → The atomic number of nickel is 28. | What is the electron configuration of nickel? → Nickel has the electron configuration [Ar] 3d⁸ 4s². | What is nickel used for? → Nickel is used in stainless steel, superalloys, plating, batteries, catalysts, coins and magnets. ### Copper (Cu) — https://ferrumone.com/en/element/copper Atom no: 29 | Transition Metal | Period 4, Group 11 **Title:** Copper: Atomic Number, Uses and Isotopes **Description:** Copper element guide: atomic number 29, symbol Cu, atomic mass 63.546, electron configuration [Ar] 3d¹⁰ 4s¹, uses, isotopes and compounds. **Keywords:** copper element, copper atomic number, copper electron configuration, copper uses, copper isotopes, copper electron configuration exception, copper conductivity, bronze brass copper, copper patina, iron copper sulfate reaction **Properties:** atomic mass 63.546 u; electron configuration [Ar] 3d¹⁰ 4s¹; state Solid; electronegativity 1.9 - **History:** Copper has been used since ancient times and helped define the Bronze Age when alloyed with tin. The symbol Cu comes from cuprum, a Latin name linked to Cyprus, an important ancient copper source. - **Isotopes:** Copper-63, About 69.2%, The most abundant stable isotope of copper.; Copper-65, About 30.8%, Stable isotope of copper. - **Compounds:** CuO (Copper(II) Oxide), Cu₂O (Copper(I) Oxide), CuSO₄·5H₂O (Copper(II) Sulfate Pentahydrate), CuCl₂ (Copper(II) Chloride), Cu₂(OH)₂CO₃ (Basic Copper Carbonate) - **Uses:** Electrical wiring and electronics because copper conducts electricity very well; Plumbing, heat exchangers and roofing due to thermal conductivity and corrosion resistance; Bronze, brass and other copper alloys; Antimicrobial surfaces in hospitals and high-touch environments; Printed circuit boards and electroplating - **Biology:** Copper is an essential trace element. It is found in enzymes involved in respiration, antioxidant defense, iron metabolism and melanin production, but excess copper can be toxic. - **Interesting:** Copper has the electron configuration exception [Ar] 3d¹⁰ 4s¹. Copper is second only to silver among common metals for electrical conductivity. The green color of aged copper surfaces comes from protective patina compounds. Bronze is mainly copper and tin, while brass is mainly copper and zinc. Iron can displace copper from copper(II) sulfate solution because iron is more reactive than copper. - **Study notes:** Copper has atomic number 29 and belongs to group 11. Its electron configuration is [Ar] 3d¹⁰ 4s¹, not [Ar] 3d⁹ 4s². Common oxidation states are +1 and +2. Cu²⁺ compounds are often blue or green, while Cu₂O is red and CuO is black. - **FAQ:** What is the atomic number of copper? → The atomic number of copper is 29. | What is the electron configuration of copper? → Copper has the electron configuration [Ar] 3d¹⁰ 4s¹. | Why is copper an electron configuration exception? → Copper has a filled 3d¹⁰ subshell and one 4s electron because the filled d subshell is especially stable. ### Zinc (Zn) — https://ferrumone.com/en/element/zinc Atom no: 30 | Transition Metal | Period 4, Group 12 **Title:** Zinc: Atomic Number, Uses and Isotopes **Description:** Zinc element guide: atomic number 30, symbol Zn, atomic mass 65.38, electron configuration [Ar] 3d¹⁰ 4s², uses, isotopes and compounds. **Keywords:** zinc element, zinc atomic number, zinc electron configuration, zinc uses, zinc isotopes, zinc galvanizing, zinc oxide sunscreen, zinc finger proteins, zinc amphoteric hydroxide **Properties:** atomic mass 65.38 u; electron configuration [Ar] 3d¹⁰ 4s²; state Solid; electronegativity 1.65 - **History:** Zinc compounds and brass were known in antiquity, and metallic zinc was produced in India before it became common in Europe. Andreas Sigismund Marggraf is often credited with isolating zinc in Europe in 1746. - **Isotopes:** Zinc-64, About 49.17%, The most abundant naturally occurring zinc isotope.; Zinc-66, About 27.73%, Stable isotope of zinc.; Zinc-67, About 4.04%, Stable isotope used in NMR and isotope studies.; Zinc-68, About 18.45%, Stable isotope of zinc.; Zinc-70, About 0.61%, Rare naturally occurring zinc isotope. - **Compounds:** ZnO (Zinc Oxide), ZnS (Zinc Sulfide), ZnCl₂ (Zinc Chloride), ZnSO₄ (Zinc Sulfate), Zn(OH)₂ (Zinc Hydroxide) - **Uses:** Galvanizing steel to protect iron from rust; Brass and other zinc-containing alloys; Zinc-carbon and alkaline batteries, where zinc acts as the anode; Zinc oxide in sunscreens, rubber, ceramics and ointments; Dietary supplements and medicines when zinc deficiency is a concern - **Biology:** Zinc is an essential trace element for humans, animals, plants and microorganisms. It supports many enzymes, immune function, wound healing, taste, smell and zinc finger proteins that regulate gene expression. - **Interesting:** Zinc protects galvanized steel by acting as a sacrificial metal before iron corrodes. Zinc has a filled 3d¹⁰ subshell and most commonly forms colorless Zn²⁺ compounds. Zinc finger proteins use Zn²⁺ to stabilize structures that bind DNA. Zinc oxide is valued because it blocks or scatters ultraviolet light in sunscreens. - **Study notes:** Zinc has atomic number 30 and belongs to group 12. Its electron configuration is [Ar] 3d¹⁰ 4s². Zinc most commonly forms Zn²⁺ and keeps a filled 3d¹⁰ configuration. Zn(OH)₂ is amphoteric, reacting with acids and with strong bases to form zincate species. - **FAQ:** What is the atomic number of zinc? → The atomic number of zinc is 30. | What is the electron configuration of zinc? → Zinc has the electron configuration [Ar] 3d¹⁰ 4s². | What is zinc used for? → Zinc is used for galvanizing steel, brass, batteries, zinc oxide products, die casting, supplements and fertilizers. ### Gallium (Ga) — https://ferrumone.com/en/element/gallium Atom no: 31 | Post-Transition Metal | Period 4, Group 13 **Title:** Gallium: Atomic Number, Uses and Isotopes **Description:** Gallium element guide: atomic number 31, symbol Ga, atomic mass 69.723, electron configuration [Ar] 3d¹⁰ 4s² 4p¹, uses, isotopes and compounds. **Keywords:** gallium element, gallium atomic number, gallium electron configuration, gallium uses, gallium isotopes, gallium melts in hand, gallium arsenide, gallium nitride LED, eka aluminum gallium **Properties:** atomic mass 69.723 u; electron configuration [Ar] 3d¹⁰ 4s² 4p¹; state Solid; electronegativity 1.81 - **History:** Gallium was discovered in 1875 by Paul-Émile Lecoq de Boisbaudran using spectroscopy. It closely matched Mendeleev’s predicted eka-aluminum, including density, atomic mass and oxide behavior. - **Isotopes:** Gallium-69, About 60.1%, The more abundant stable isotope of gallium.; Gallium-71, About 39.9%, Stable isotope of gallium. - **Compounds:** GaAs (Gallium Arsenide), GaN (Gallium Nitride), Ga₂O₃ (Gallium(III) Oxide), GaCl₃ (Gallium(III) Chloride) - **Uses:** Gallium arsenide semiconductors for high-speed electronics, LEDs and solar cells; Gallium nitride for blue and white LEDs, laser diodes and power electronics; Low-melting alloys such as gallium-indium-tin mixtures; Gallium compounds in nuclear medicine and imaging research; Thermal interface materials and liquid-metal cooling research - **Biology:** Gallium has no known essential biological role. Ga³⁺ can mimic Fe³⁺ in some biological systems, which is why gallium compounds have been studied in medical and antimicrobial contexts. - **Interesting:** Gallium melts at about 29.8 °C, so it can melt in a warm hand. Gallium nitride blue LEDs helped make efficient white LED lighting possible. Liquid gallium can weaken aluminum by penetrating its grain boundaries. Gallium was a major success for Mendeleev’s periodic table predictions. - **Study notes:** Gallium has atomic number 31 and belongs to group 13. Its electron configuration is [Ar] 3d¹⁰ 4s² 4p¹. Gallium commonly forms Ga³⁺ and many gallium compounds show +3 oxidation state chemistry. Gallium sits after the 3d transition series, so its chemistry is influenced by the filled 3d¹⁰ subshell. - **FAQ:** What is the atomic number of gallium? → The atomic number of gallium is 31. | What is the electron configuration of gallium? → Gallium has the electron configuration [Ar] 3d¹⁰ 4s² 4p¹. | Why does gallium melt in your hand? → Gallium melts near 29.8 °C, which is below normal body temperature, so a warm hand can melt it slowly. ### Germanium (Ge) — https://ferrumone.com/en/element/germanium Atom no: 32 | Metalloid | Period 4, Group 14 **Title:** Germanium: Atomic Number, Uses and Isotopes **Description:** Germanium element guide: atomic number 32, symbol Ge, atomic mass 72.63, electron configuration [Ar] 3d¹⁰ 4s² 4p², uses, isotopes and compounds. **Keywords:** germanium element, germanium atomic number, germanium electron configuration, germanium uses, germanium isotopes, germanium semiconductor, germanium infrared optics, eka silicon germanium, germanium fiber optics **Properties:** atomic mass 72.63 u; electron configuration [Ar] 3d¹⁰ 4s² 4p²; state Solid; electronegativity 2.01 - **History:** Germanium was discovered in 1886 by Clemens Winkler in the mineral argyrodite. Its properties closely matched Mendeleev’s predicted eka-silicon, another strong validation of the periodic table. - **Isotopes:** Germanium-70, About 20.5%, Stable isotope of germanium.; Germanium-72, About 27.4%, Stable isotope of germanium.; Germanium-73, About 7.8%, Stable isotope used in NMR studies.; Germanium-74, About 36.5%, The most abundant stable isotope of germanium.; Germanium-76, About 7.8%, Long-lived isotope studied in double beta decay experiments. - **Compounds:** GeO₂ (Germanium Dioxide), GeCl₄ (Germanium Tetrachloride), GeS₂ (Germanium Disulfide), SiGe (Silicon-Germanium Alloy) - **Uses:** Infrared optics for thermal cameras and night-vision equipment; Germanium dioxide in fiber-optic glass to adjust refractive index; Silicon-germanium alloys in high-speed transistors and RF electronics; Substrates for high-efficiency multi-junction solar cells; Historical semiconductor material in early transistors - **Biology:** Germanium has no known essential biological role. Some organogermanium compounds have been marketed as supplements, but essentiality and broad health benefits are not scientifically established. - **Interesting:** The first transistor demonstrated at Bell Labs in 1947 used germanium. Germanium is opaque to visible light but transparent to much infrared radiation. Germanium dioxide can raise the refractive index of silica glass in optical fibers. Germanium was discovered after Mendeleev predicted eka-silicon with striking accuracy. - **Study notes:** Germanium has atomic number 32 and belongs to group 14. Its electron configuration is [Ar] 3d¹⁰ 4s² 4p². Germanium is a metalloid and semiconductor, like silicon. Common oxidation states are +4 and +2, with +4 more common in compounds such as GeO₂. - **FAQ:** What is the atomic number of germanium? → The atomic number of germanium is 32. | What is the electron configuration of germanium? → Germanium has the electron configuration [Ar] 3d¹⁰ 4s² 4p². | What is germanium used for? → Germanium is used in infrared optics, fiber optics, silicon-germanium electronics, solar cells and semiconductor research. ### Arsenic (As) — https://ferrumone.com/en/element/arsenic Atom no: 33 | Metalloid | Period 4, Group 15 **Title:** Arsenic: Atomic Number, Uses and Isotopes **Description:** Arsenic element guide: atomic number 33, symbol As, atomic mass 74.922, electron configuration [Ar] 3d¹⁰ 4s² 4p³, allotropes, toxicity and compounds. **Keywords:** arsenic element, arsenic atomic number, arsenic electron configuration, arsenic uses, arsenic isotopes, arsenic toxicity, arsenic allotropes, gallium arsenide, arsenic groundwater contamination **Properties:** atomic mass 74.922 u; electron configuration [Ar] 3d¹⁰ 4s² 4p³; state Solid; electronegativity 2.18 - **History:** Arsenic compounds were known in antiquity as pigments and poisons. Metallic arsenic is often associated with Albertus Magnus in the 13th century, and arsenic later became famous in the history of toxicology and forensic chemistry. - **Isotopes:** Arsenic-75, 100%, The only stable naturally occurring isotope of arsenic. - **Allotropes:** Gray Arsenic (Most stable metallic-looking allotrope with a rhombohedral structure and semimetal behavior.); Yellow Arsenic (Molecular As₄ form that is unstable and can transform into gray arsenic.); Black Arsenic (Amorphous or layered form produced under special conditions and less common than gray arsenic.) - **Compounds:** As₂O₃ (Arsenic Trioxide), AsH₃ (Arsine), As₂S₃ (Arsenic Trisulfide), As₄S₄ (Realgar), GaAs (Gallium Arsenide) - **Uses:** Gallium arsenide semiconductors for electronics and optoelectronics; Arsenic trioxide in specific cancer treatment protocols such as acute promyelocytic leukemia; Historical pigments such as orpiment and realgar; Specialty glass and semiconductor doping applications; Lead alloy hardening in limited specialized uses - **Biology:** Arsenic has no confirmed essential role in humans. Inorganic arsenic is toxic and carcinogenic, while a few arsenic compounds have specialized medical uses under strict control. - **Interesting:** Arsenic-75 is monoisotopic, so natural arsenic has one stable isotope. Arsenic contamination of groundwater is a major environmental health problem in some regions. The Marsh test was an early forensic chemistry method for detecting arsenic. Gray arsenic is the most stable allotrope under ordinary conditions. - **Study notes:** Arsenic has atomic number 33 and belongs to group 15. Its electron configuration is [Ar] 3d¹⁰ 4s² 4p³. Arsenic is a metalloid and commonly shows oxidation states -3, +3 and +5. Toxicity depends strongly on chemical form; inorganic arsenic compounds are especially hazardous. - **FAQ:** What is the atomic number of arsenic? → The atomic number of arsenic is 33. | What is the electron configuration of arsenic? → Arsenic has the electron configuration [Ar] 3d¹⁰ 4s² 4p³. | Is arsenic toxic? → Yes. Inorganic arsenic compounds are toxic and carcinogenic, so exposure must be carefully controlled. ### Selenium (Se) — https://ferrumone.com/en/element/selenium Atom no: 34 | Nonmetal | Period 4, Group 16 **Title:** Selenium: Atomic Number, Uses and Isotopes **Description:** Selenium element guide: atomic number 34, symbol Se, atomic mass 78.971, electron configuration [Ar] 3d¹⁰ 4s² 4p⁴, allotropes, uses and isotopes. **Keywords:** selenium element, selenium atomic number, selenium electron configuration, selenium uses, selenium isotopes, selenium allotropes, selenium photoconductive, selenocysteine, selenium deficiency toxicity **Properties:** atomic mass 78.971 u; electron configuration [Ar] 3d¹⁰ 4s² 4p⁴; state Solid; electronegativity 2.55 - **History:** Selenium was discovered in 1817 by Jöns Jacob Berzelius while examining residues from sulfuric acid production. It was named after Selene, the Moon, because of its relationship to tellurium, named after Earth. - **Isotopes:** Selenium-74, About 0.89%, Stable isotope of selenium.; Selenium-76, About 9.37%, Stable isotope of selenium.; Selenium-77, About 7.63%, Stable isotope used in NMR studies.; Selenium-78, About 23.8%, Stable isotope of selenium.; Selenium-80, About 49.6%, The most abundant stable isotope of selenium.; Selenium-82, About 8.7%, Long-lived isotope studied in double beta decay research. - **Allotropes:** Gray Selenium (Most stable crystalline selenium form with a trigonal chain structure and photoconductive behavior.); Red Selenium (Form based on Se₈ ring molecules; can occur as amorphous or monoclinic selenium.); Black Selenium (Glassy amorphous selenium produced by rapid cooling of molten selenium.) - **Compounds:** SeO₂ (Selenium Dioxide), H₂Se (Hydrogen Selenide), Na₂SeO₃ (Sodium Selenite), SeS₂ (Selenium Sulfide), Cu(In,Ga)Se₂ (CIGS Absorber) - **Uses:** Photoconductive materials in historical photocopiers and light sensors; Glass decolorizing and red or pink glass coloring; CIGS thin-film solar cells and related semiconductor materials; Selenium sulfide in some anti-dandruff products; Dietary and animal feed supplementation in controlled amounts - **Biology:** Selenium is an essential trace element. It occurs in selenocysteine-containing proteins involved in antioxidant defense, thyroid hormone metabolism and redox regulation, but excess selenium can be toxic. - **Interesting:** Selenocysteine is often called the 21st amino acid. Gray selenium conducts electricity better when exposed to light. The safe intake range for selenium is narrow: both deficiency and excess can be harmful. CIGS solar cells rely on selenium-containing semiconductor materials. - **Study notes:** Selenium has atomic number 34 and belongs to group 16, the chalcogens. Its electron configuration is [Ar] 3d¹⁰ 4s² 4p⁴. Common oxidation states include -2, +4 and +6. Selenium is chemically related to sulfur but has stronger metalloid-like and photoconductive behavior in some forms. - **FAQ:** What is the atomic number of selenium? → The atomic number of selenium is 34. | What is the electron configuration of selenium? → Selenium has the electron configuration [Ar] 3d¹⁰ 4s² 4p⁴. | Why is selenium important for the body? → Selenium is needed in selenoproteins involved in antioxidant defense, thyroid hormone metabolism and redox regulation. ### Bromine (Br) — https://ferrumone.com/en/element/bromine Atom no: 35 | Halogen | Period 4, Group 17 **Title:** Bromine: Atomic Number, Uses and Isotopes **Description:** Bromine element guide: atomic number 35, symbol Br, atomic mass 79.904, electron configuration [Ar] 3d¹⁰ 4s² 4p⁵, uses, isotopes and compounds. **Keywords:** bromine element, bromine atomic number, bromine electron configuration, bromine uses, bromine isotopes, liquid nonmetal bromine, silver bromide photography, bromine flame retardants, bromine mass spectrum **Properties:** atomic mass 79.904 u; electron configuration [Ar] 3d¹⁰ 4s² 4p⁵; state Liquid; electronegativity 2.96 - **History:** Bromine was discovered independently by Carl Jacob Löwig and Antoine-Jérôme Balard in the 1820s. Its name comes from the Greek bromos, meaning stench, because bromine has a strong irritating odor. - **Isotopes:** Bromine-79, About 50.7%, Stable isotope of bromine.; Bromine-81, About 49.3%, Stable isotope of bromine; nearly equal abundance creates a characteristic mass spectrum pattern. - **Compounds:** HBr (Hydrogen Bromide), AgBr (Silver Bromide), NaBr (Sodium Bromide), NBS (N-Bromosuccinimide), CH₃Br (Methyl Bromide) - **Uses:** Brominated flame retardants in plastics and textiles, with restrictions on some persistent compounds; Silver bromide in traditional photographic film and paper; Water treatment and pool chemistry using bromine-releasing compounds; Organic synthesis, including bromination reactions; Some pharmaceuticals, dyes and specialty chemicals - **Biology:** Bromide may have specialized biological roles in some organisms and connective-tissue chemistry, but bromine is not usually treated as a major essential nutrient for humans. - **Interesting:** Bromine is the only nonmetal that is liquid at room temperature. The two main bromine isotopes have nearly equal abundance, giving brominated molecules a distinctive M and M+2 mass spectrum pattern. Silver bromide made film photography possible because it darkens through light-sensitive chemistry. Bromine vapor is corrosive and hazardous, so elemental bromine requires careful handling. - **Study notes:** Bromine has atomic number 35 and belongs to group 17, the halogens. Its electron configuration is [Ar] 3d¹⁰ 4s² 4p⁵. Bromine commonly forms Br⁻ in bromide salts. Halogen reactivity generally decreases down the group from fluorine to iodine, so bromine is less reactive than chlorine but more reactive than iodine. - **FAQ:** What is the atomic number of bromine? → The atomic number of bromine is 35. | What is the electron configuration of bromine? → Bromine has the electron configuration [Ar] 3d¹⁰ 4s² 4p⁵. | Is bromine a liquid at room temperature? → Yes. Bromine is the only nonmetal that is liquid at room temperature. ### Krypton (Kr) — https://ferrumone.com/en/element/krypton Atom no: 36 | Noble Gas | Period 4, Group 18 **Title:** Krypton: Atomic Number, Uses and Isotopes **Description:** Krypton element guide: atomic number 36, symbol Kr, atomic mass 83.798, electron configuration [Ar] 3d¹⁰ 4s² 4p⁶, uses, isotopes and compounds. **Keywords:** krypton element, krypton atomic number, krypton electron configuration, krypton uses, krypton isotopes, krypton noble gas, krypton fluoride laser, krypton meter definition, krypton 85, krypton compounds **Properties:** atomic mass 83.798 u; electron configuration [Ar] 3d¹⁰ 4s² 4p⁶; state Gas; electronegativity 3 - **History:** Krypton was discovered in 1898 by William Ramsay and Morris Travers during fractional distillation of liquid air. Its name comes from the Greek kryptos, meaning hidden. - **Isotopes:** Krypton-78, About 0.36%, Stable isotope of krypton.; Krypton-80, About 2.29%, Stable isotope of krypton.; Krypton-82, About 11.6%, Stable isotope of krypton.; Krypton-83, About 11.5%, Stable isotope used in NMR and materials studies.; Krypton-84, About 57.0%, The most abundant stable isotope of krypton.; Krypton-85, Synthetic / trace atmospheric, t½=About 10.8 years, Radioactive fission product used in nuclear monitoring and specialized industrial applications.; Krypton-86, About 17.3%, Stable isotope once used in the meter definition. - **Compounds:** KrF₂ (Krypton Difluoride) - **Uses:** Krypton fluoride excimer lasers for ultraviolet lithography and research; High-speed photography flash lamps; Specialty lighting and energy-saving fluorescent lamps; Insulating gas in some high-performance windows; Krypton-85 in monitoring and specialized industrial applications - **Biology:** Krypton has no known biological role. It is chemically inert under ordinary conditions and can act as an asphyxiant by displacing oxygen in confined spaces. - **Interesting:** Krypton-86 light was used to define the meter from 1960 to 1983. Krypton fluoride excimer lasers emit deep ultraviolet light used in lithography and research. Krypton is a noble gas, but krypton difluoride shows that noble gas compounds can exist under special conditions. The fictional planet Krypton made the element famous in popular culture. - **Study notes:** Krypton has atomic number 36 and belongs to group 18, the noble gases. Its electron configuration is [Ar] 3d¹⁰ 4s² 4p⁶. Krypton has a full valence shell and is monatomic under ordinary conditions. Noble gases are generally inert, but heavier noble gases can form rare compounds with highly reactive elements such as fluorine. - **FAQ:** What is the atomic number of krypton? → The atomic number of krypton is 36. | What is the electron configuration of krypton? → Krypton has the electron configuration [Ar] 3d¹⁰ 4s² 4p⁶. | Is krypton a noble gas? → Yes. Krypton is a group 18 noble gas. ### Rubidium (Rb) — https://ferrumone.com/en/element/rubidium Atom no: 37 | Alkali Metal | Period 5, Group 1 **Title:** Rubidium: Atomic Number, Uses and Isotopes **Description:** Rubidium element guide: atomic number 37, symbol Rb, atomic mass 85.468, electron configuration [Kr] 5s¹, uses, isotopes and compounds. **Keywords:** rubidium element, rubidium atomic number, rubidium electron configuration, rubidium uses, rubidium isotopes, rubidium atomic clock, rubidium strontium dating, rubidium flame color, rubidium 87 **Properties:** atomic mass 85.468 u; electron configuration [Kr] 5s¹; state Solid; electronegativity 0.82 - **History:** Rubidium was discovered in 1861 by Robert Bunsen and Gustav Kirchhoff using spectroscopy. Its name comes from the Latin rubidus, meaning deep red, referring to its spectral lines. - **Isotopes:** Rubidium-85, About 72.2%, The most abundant stable isotope of rubidium.; Rubidium-87, About 27.83%, t½=About 4.97 x 10¹⁰ years, Long-lived radioactive isotope used in Rb-Sr dating.; Rubidium-82, Synthetic, t½=About 75 seconds, Positron-emitting isotope used in cardiac PET imaging. - **Compounds:** RbCl (Rubidium Chloride), RbOH (Rubidium Hydroxide), Rb₂CO₃ (Rubidium Carbonate), RbNO₃ (Rubidium Nitrate) - **Uses:** Rubidium atomic clocks and frequency standards; Rubidium vapor cells in magnetometers and physics experiments; Rubidium-strontium dating using the decay of rubidium-87; Specialty glass and photocathode research; Rubidium-82 PET imaging for cardiac blood-flow studies - **Biology:** Rubidium has no confirmed essential biological role. Rb⁺ resembles K⁺ chemically, so rubidium can sometimes follow potassium pathways in biological and medical tracer contexts. - **Interesting:** Rubidium is much more reactive than potassium and can ignite in air or react violently with water. Rubidium-87 decays to strontium-87, enabling Rb-Sr radiometric dating. Rubidium atomic clocks are compact frequency standards used in telecommunications and navigation systems. Rubidium atoms were used in landmark Bose-Einstein condensate experiments. - **Study notes:** Rubidium has atomic number 37 and belongs to group 1, the alkali metals. Its electron configuration is [Kr] 5s¹. Rubidium commonly forms Rb⁺ by losing one valence electron. Alkali metal reactivity generally increases down the group, so rubidium is more reactive than potassium. - **FAQ:** What is the atomic number of rubidium? → The atomic number of rubidium is 37. | What is the electron configuration of rubidium? → Rubidium has the electron configuration [Kr] 5s¹. | What is rubidium used for? → Rubidium is used in atomic clocks, vapor-cell instruments, Rb-Sr dating, specialty glass, research and rubidium-82 PET imaging. ### Strontium (Sr) — https://ferrumone.com/en/element/strontium Atom no: 38 | Alkaline Earth Metal | Period 5, Group 2 **Title:** Strontium: Atomic Number, Uses and Isotopes **Description:** Strontium element guide: atomic number 38, symbol Sr, atomic mass 87.62, electron configuration [Kr] 5s², uses, isotopes and compounds. **Keywords:** strontium element, strontium atomic number, strontium electron configuration, strontium uses, strontium isotopes, strontium flame test, strontium red fireworks, strontium 90, strontium isotope dating **Properties:** atomic mass 87.62 u; electron configuration [Kr] 5s²; state Solid; electronegativity 0.95 - **History:** Strontium was identified from minerals found near Strontian in Scotland. The metal was isolated by Humphry Davy in 1808 by electrolysis, and the element is named after the village. - **Isotopes:** Strontium-84, About 0.56%, Rare stable isotope of strontium.; Strontium-86, About 9.86%, Stable isotope used as a reference in isotope ratio studies.; Strontium-87, About 7.0%, Stable isotope partly produced by rubidium-87 decay.; Strontium-88, About 82.6%, The most abundant stable isotope of strontium.; Strontium-90, Synthetic, t½=About 28.9 years, Radioactive fission product and important nuclear fallout isotope. - **Compounds:** SrCO₃ (Strontium Carbonate), Sr(NO₃)₂ (Strontium Nitrate), SrAl₂O₄ (Strontium Aluminate), SrTiO₃ (Strontium Titanate), SrSO₄ (Strontium Sulfate) - **Uses:** Red fireworks and signal flares from strontium salts; Strontium aluminate glow-in-the-dark pigments; Ferrite magnets and specialty ceramics; Historical CRT glass applications for X-ray absorption; Strontium isotope ratios in geology, archaeology and migration studies - **Biology:** Strontium has no confirmed essential role in humans. Sr²⁺ behaves somewhat like Ca²⁺ and can enter bones; radioactive strontium-90 is hazardous because it can concentrate in bone tissue. - **Interesting:** Strontium compounds give a bright red flame color. Strontium aluminate pigments can glow for hours after light exposure. Strontium-90 is dangerous because Sr²⁺ can behave like Ca²⁺ and enter bone. Strontium isotope ratios can help trace where people, animals or rocks originated. - **Study notes:** Strontium has atomic number 38 and belongs to group 2, the alkaline earth metals. Its electron configuration is [Kr] 5s². Strontium commonly forms Sr²⁺ by losing two valence electrons. Strontium flame tests are bright red, helping distinguish it from calcium and barium. - **FAQ:** What is the atomic number of strontium? → The atomic number of strontium is 38. | What is the electron configuration of strontium? → Strontium has the electron configuration [Kr] 5s². | What color is strontium in a flame test? → Strontium gives a bright red flame color, which is why it is used in red fireworks and flares. ### Yttrium (Y) — https://ferrumone.com/en/element/yttrium Atom no: 39 | Transition Metal | Period 5, Group 3 **Title:** Yttrium: Atomic Number, Uses and Isotopes **Description:** Yttrium element guide: atomic number 39, symbol Y, atomic mass 88.906, electron configuration [Kr] 4d¹ 5s², uses, isotopes and compounds. **Keywords:** yttrium element, yttrium atomic number, yttrium electron configuration, yttrium uses, yttrium isotopes, YAG laser, YBCO superconductor, yttrium 90, Ytterby elements **Properties:** atomic mass 88.906 u; electron configuration [Kr] 4d¹ 5s²; state Solid; electronegativity 1.22 - **History:** Yttrium was discovered in minerals from Ytterby, Sweden, by Johan Gadolin in 1794. Ytterby is famous because several element names are linked to minerals from that village. - **Isotopes:** Yttrium-89, 100%, The only stable naturally occurring isotope of yttrium.; Yttrium-90, Synthetic, t½=About 64.1 hours, Radioactive beta emitter used in cancer therapy applications. - **Compounds:** Y₂O₃ (Yttrium Oxide), Y₃Al₅O₁₂ (Yttrium Aluminum Garnet (YAG)), YBa₂Cu₃O₇ (YBCO), YCl₃ (Yttrium Chloride) - **Uses:** YAG laser crystals for medicine, industry and research; YBCO high-temperature superconductors; Yttria-stabilized zirconia for ceramics, dental materials and oxygen sensors; Phosphors in lighting and display technologies; Yttrium-90 radioembolization and radiotherapy applications - **Biology:** Yttrium has no known essential biological role. The radioisotope yttrium-90 is used in targeted medical treatments under strict clinical control. - **Interesting:** Ytterby, Sweden, is connected to the names of yttrium, terbium, erbium and ytterbium. YBCO was one of the first superconductors to work above liquid nitrogen temperature. Nd:YAG lasers use yttrium aluminum garnet as the host crystal. Yttrium-90 microspheres are used in targeted liver cancer treatment. - **Study notes:** Yttrium has atomic number 39 and belongs to group 3. Its electron configuration is [Kr] 4d¹ 5s². Yttrium commonly forms Y³⁺ and resembles some rare-earth elements chemically. Y³⁺ has a d⁰ configuration, so many simple yttrium compounds are colorless. - **FAQ:** What is the atomic number of yttrium? → The atomic number of yttrium is 39. | What is the electron configuration of yttrium? → Yttrium has the electron configuration [Kr] 4d¹ 5s². | What is yttrium used for? → Yttrium is used in YAG lasers, superconductors, phosphors, stabilized zirconia ceramics and yttrium-90 medical therapy. ### Zirconium (Zr) — https://ferrumone.com/en/element/zirconium Atom no: 40 | Transition Metal | Period 5, Group 4 **Title:** Zirconium: Atomic Number, Uses and Isotopes **Description:** Zirconium element guide: atomic number 40, symbol Zr, atomic mass 91.224, electron configuration [Kr] 4d² 5s², uses, isotopes and compounds. **Keywords:** zirconium element, zirconium atomic number, zirconium electron configuration, zirconium uses, zirconium isotopes, zirconium nuclear reactors, zircaloy fuel cladding, zirconium dioxide, zirconium hafnium separation, cubic zirconia **Properties:** atomic mass 91.224 u; electron configuration [Kr] 4d² 5s²; state Solid; electronegativity 1.33 - **History:** Zirconium was identified by Martin Heinrich Klaproth in 1789 from zircon minerals. Metallic zirconium was later prepared by Jöns Jacob Berzelius, and modern nuclear uses depend on separating zirconium from chemically similar hafnium. - **Isotopes:** Zirconium-90, About 51.5%, The most abundant stable isotope of zirconium.; Zirconium-91, About 11.2%, Stable isotope of zirconium.; Zirconium-92, About 17.1%, Stable isotope of zirconium.; Zirconium-94, About 17.4%, Stable isotope of zirconium.; Zirconium-96, About 2.8%, Very long-lived isotope studied in nuclear science. - **Compounds:** ZrO₂ (Zirconium Dioxide), ZrSiO₄ (Zircon), ZrCl₄ (Zirconium Tetrachloride), ZrB₂ (Zirconium Diboride) - **Uses:** Zircaloy fuel cladding in nuclear reactors because zirconium absorbs few thermal neutrons; Zirconium dioxide ceramics for dental crowns, oxygen sensors and high-temperature materials; Cubic zirconia gemstones and optical materials; Zircon minerals in U-Pb radiometric dating; Refractory ceramics and corrosion-resistant chemical equipment - **Biology:** Zirconium has no known essential biological role. Zirconia ceramics are biocompatible and are used in dental and medical materials. - **Interesting:** Zirconium is used in nuclear reactors because it has a low neutron absorption tendency. Hafnium must be removed from nuclear-grade zirconium because hafnium absorbs neutrons strongly. Zircon crystals can preserve uranium-lead ages for billions of years. Zirconia ceramics can resist crack growth through transformation toughening. - **Study notes:** Zirconium has atomic number 40 and belongs to group 4. Its electron configuration is [Kr] 4d² 5s². The most common oxidation state is +4. Zirconium and hafnium are difficult to separate because their ionic sizes are very similar due to the lanthanide contraction. - **FAQ:** What is the atomic number of zirconium? → The atomic number of zirconium is 40. | What is the electron configuration of zirconium? → Zirconium has the electron configuration [Kr] 4d² 5s². | What is zirconium used for? → Zirconium is used in nuclear reactor fuel cladding, zirconia ceramics, oxygen sensors, refractory materials, gemstones and corrosion-resistant equipment. ### Niobium (Nb) — https://ferrumone.com/en/element/niobium Atom no: 41 | Transition Metal | Period 5, Group 5 **Title:** Niobium: Atomic Number, Uses and Isotopes **Description:** Niobium element guide: atomic number 41, symbol Nb, atomic mass 92.906, electron configuration [Kr] 4d⁴ 5s¹, superconductors, steel alloys and compounds. **Keywords:** niobium element, niobium atomic number, niobium electron configuration, niobium uses, niobium isotopes, niobium superconducting magnets, niobium titanium alloy, Nb3Sn superconductor, columbium niobium **Properties:** atomic mass 92.906 u; electron configuration [Kr] 4d⁴ 5s¹; state Solid; electronegativity 1.6 - **History:** Niobium was discovered in 1801 by Charles Hatchett in columbite and was first called columbium. Heinrich Rose later distinguished it from tantalum and proposed the name niobium, which IUPAC adopted officially. - **Isotopes:** Niobium-93, 100%, The only stable naturally occurring isotope of niobium. - **Compounds:** Nb₂O₅ (Niobium Pentoxide), NbC (Niobium Carbide), LiNbO₃ (Lithium Niobate), Nb₃Sn (Niobium-Tin) - **Uses:** Ferroniobium in high-strength low-alloy steel for pipelines, bridges and vehicles; Niobium-titanium superconducting magnets in MRI scanners and particle accelerators; Nb₃Sn superconductors for high-field magnets; High-temperature alloys for aerospace and jet-engine components; Niobium oxide in optical glass, capacitors and specialty ceramics - **Biology:** Niobium has no known essential biological role. - **Interesting:** Niobium has the electron configuration [Kr] 4d⁴ 5s¹, an exception from a simple filling pattern. Small niobium additions can greatly strengthen steel without adding much weight. Niobium-titanium wires are widely used in superconducting MRI and accelerator magnets. The older name columbium is still encountered in some industrial contexts. - **Study notes:** Niobium has atomic number 41 and belongs to group 5. Its electron configuration is [Kr] 4d⁴ 5s¹. The most common oxidation state is +5, as in Nb₂O₅. Niobium-93 makes natural niobium monoisotopic. - **FAQ:** What is the atomic number of niobium? → The atomic number of niobium is 41. | What is the electron configuration of niobium? → Niobium has the electron configuration [Kr] 4d⁴ 5s¹. | What is niobium used for? → Niobium is used in high-strength steel, superconducting magnets, aerospace alloys, optical glass and specialty compounds. ### Molybdenum (Mo) — https://ferrumone.com/en/element/molybdenum Atom no: 42 | Transition Metal | Period 5, Group 6 **Title:** Molybdenum: Atomic Number, Uses and Isotopes **Description:** Molybdenum element guide: atomic number 42, symbol Mo, atomic mass 95.95, electron configuration [Kr] 4d⁵ 5s¹, uses, isotopes and compounds. **Keywords:** molybdenum element, molybdenum atomic number, molybdenum electron configuration, molybdenum uses, molybdenum isotopes, molybdenum disulfide lubricant, molybdenum cofactor, molybdenum 99 technetium 99m, MoS2 lubricant **Properties:** atomic mass 95.95 u; electron configuration [Kr] 4d⁵ 5s¹; state Solid; electronegativity 2.16 - **History:** Molybdenum was identified after molybdenite was shown to be different from graphite and lead minerals. Carl Wilhelm Scheele described molybdic acid, and Peter Jacob Hjelm isolated the metal in the 18th century. - **Isotopes:** Molybdenum-92, About 14.5%, Stable isotope of molybdenum.; Molybdenum-94, About 9.2%, Stable isotope of molybdenum.; Molybdenum-95, About 15.8%, Stable isotope used in NMR studies.; Molybdenum-96, About 16.7%, Stable isotope of molybdenum.; Molybdenum-97, About 9.6%, Stable isotope of molybdenum.; Molybdenum-98, About 24.4%, The most abundant stable isotope of molybdenum.; Molybdenum-100, About 9.8%, Long-lived isotope studied in double beta decay research. - **Compounds:** MoS₂ (Molybdenum Disulfide), MoO₃ (Molybdenum Trioxide), (NH₄)₂MoO₄ (Ammonium Molybdate) - **Uses:** Steel alloys that need high strength, hardness and heat resistance; Molybdenum disulfide dry lubricants for high-load and vacuum conditions; Hydrodesulfurization catalysts in petroleum refining; Molybdenum-99 production for technetium-99m medical imaging; High-temperature furnace parts, electrodes and specialty electronics - **Biology:** Molybdenum is an essential trace element. It is part of molybdenum cofactors in enzymes such as sulfite oxidase, xanthine oxidase and nitrate reductase, and it is central to nitrogenase chemistry in some nitrogen-fixing microbes. - **Interesting:** Molybdenum has the electron configuration [Kr] 4d⁵ 5s¹, similar to chromium’s half-filled d-subshell pattern. MoS₂ works as a dry lubricant because its layers slide over each other. Molybdenum-99 is the parent isotope used to generate technetium-99m for nuclear medicine. Molybdenum enzymes connect this element directly to sulfur, nitrogen and purine metabolism. - **Study notes:** Molybdenum has atomic number 42 and belongs to group 6. Its electron configuration is [Kr] 4d⁵ 5s¹. Common oxidation states include +6 and +4. MoS₂ should be treated as a compound, not an allotrope. - **FAQ:** What is the atomic number of molybdenum? → The atomic number of molybdenum is 42. | What is the electron configuration of molybdenum? → Molybdenum has the electron configuration [Kr] 4d⁵ 5s¹. | What is molybdenum used for? → Molybdenum is used in steel alloys, dry lubricants, petroleum catalysts, high-temperature parts and medical isotope production. ### Technetium (Tc) — https://ferrumone.com/en/element/technetium Atom no: 43 | Transition Metal | Period 5, Group 7 **Title:** Technetium: Atomic Number, Uses and Isotopes **Description:** Technetium element guide: atomic number 43, symbol Tc, atomic mass 98, electron configuration [Kr] 4d⁵ 5s², technetium-99m, isotopes and compounds. **Keywords:** technetium element, technetium atomic number, technetium electron configuration, technetium uses, technetium isotopes, technetium 99m, technetium no stable isotopes, first artificial element, pertechnetate ion **Properties:** atomic mass 98 u; electron configuration [Kr] 4d⁵ 5s²; state Solid; electronegativity 1.9 - **History:** Technetium was synthesized in 1937 by Carlo Perrier and Emilio Segrè after Mendeleev’s predicted eka-manganese gap had remained empty. Its name comes from a Greek word meaning artificial. - **Isotopes:** Technetium-97, t½=About 4.21 million years, Long-lived radioactive isotope of technetium; older secondary summaries may round differently.; Technetium-98, t½=About 4.2 million years, Long-lived radioactive isotope of technetium; some reference tables report higher rounded values.; Technetium-99, t½=About 211,000 years, Long-lived fission product and decay product of technetium-99m.; Technetium-99m, t½=About 6 hours, Metastable gamma emitter used in diagnostic nuclear medicine. - **Compounds:** TcO₄⁻ (Pertechnetate Ion), Tc₂O₇ (Technetium Heptoxide) - **Uses:** Technetium-99m radiopharmaceuticals for diagnostic medical imaging; Pertechnetate imaging of thyroid and other tissues; Bone, heart, kidney and lung scans using labeled technetium compounds; Nuclear chemistry research and tracer studies - **Biology:** Technetium has no biological role. All technetium isotopes are radioactive. - **Interesting:** Technetium was the first element to be produced artificially. No isotope of technetium is stable. Technetium-99m emits gamma radiation suitable for medical imaging and has a short half-life. Trace natural technetium can occur from uranium fission, but it is not a stable primordial element. - **Study notes:** Technetium has atomic number 43 and belongs to group 7. Its electron configuration is [Kr] 4d⁵ 5s². Technetium and promethium are the two elements below bismuth with no stable isotopes. Technetium-99m comes from molybdenum-99 generators in medical use. - **FAQ:** What is the atomic number of technetium? → The atomic number of technetium is 43. | What is the atomic mass of technetium? → Technetium has no stable isotopes; many periodic tables list its relative atomic mass as about 98. | What is the electron configuration of technetium? → Technetium has the electron configuration [Kr] 4d⁵ 5s². ### Ruthenium (Ru) — https://ferrumone.com/en/element/ruthenium Atom no: 44 | Transition Metal | Period 5, Group 8 **Title:** Ruthenium: Atomic Number, Uses and Isotopes **Description:** Ruthenium element guide: atomic number 44, symbol Ru, atomic mass 101.07, electron configuration [Kr] 4d⁷ 5s¹, uses, isotopes and compounds. **Keywords:** ruthenium element, ruthenium atomic number, ruthenium electron configuration, ruthenium uses, ruthenium isotopes, ruthenium dioxide electrode, ruthenium catalyst, ruthenium solar cells, platinum group metal ruthenium **Properties:** atomic mass 101.07 u; electron configuration [Kr] 4d⁷ 5s¹; state Solid; electronegativity 2.2 - **History:** Ruthenium was isolated in 1844 by Karl Ernst Claus from platinum ore residues. Its name refers to Ruthenia, a historical Latin name associated with Russian lands. - **Isotopes:** Ruthenium-96, About 5.5%, Stable isotope of ruthenium.; Ruthenium-98, About 1.9%, Stable isotope of ruthenium.; Ruthenium-99, About 12.8%, Stable isotope of ruthenium.; Ruthenium-100, About 12.6%, Stable isotope of ruthenium.; Ruthenium-101, About 17.1%, Stable isotope of ruthenium.; Ruthenium-102, About 31.6%, The most abundant stable isotope of ruthenium.; Ruthenium-104, About 18.6%, Stable isotope of ruthenium. - **Compounds:** RuO₂ (Ruthenium Dioxide), RuCl₃ (Ruthenium(III) Chloride), Ru(bpy)₃²⁺ (Tris(bipyridine)ruthenium(II)) - **Uses:** Hardening platinum and palladium alloys; RuO₂ electrode coatings in electrochemical and chlor-alkali applications; Catalysts for chemical synthesis and ammonia-related chemistry; Ruthenium complexes in dye-sensitized solar cell research; Thin films and magnetic layers in electronic data storage - **Biology:** Ruthenium has no known essential biological role. - **Interesting:** Ruthenium is a platinum-group metal. RuO₂ coatings can act as durable anodes in harsh electrochemical environments. Ruthenium complexes are famous in photochemistry and dye-sensitized solar cell research. Ruthenium has an electron configuration exception: [Kr] 4d⁷ 5s¹. - **Study notes:** Ruthenium has atomic number 44 and belongs to group 8. Its electron configuration is [Kr] 4d⁷ 5s¹. Ruthenium can show many oxidation states, including +2, +3, +4 and +8. Ruthenium belongs to the platinum-group metals with Ru, Rh, Pd, Os, Ir and Pt. - **FAQ:** What is the atomic number of ruthenium? → The atomic number of ruthenium is 44. | What is the electron configuration of ruthenium? → Ruthenium has the electron configuration [Kr] 4d⁷ 5s¹. | What is ruthenium used for? → Ruthenium is used in catalysts, electrode coatings, electronics, alloy hardening, solar-cell research and specialty chemical systems. ### Rhodium (Rh) — https://ferrumone.com/en/element/rhodium Atom no: 45 | Transition Metal | Period 5, Group 9 **Title:** Rhodium: Atomic Number, Uses and Isotopes **Description:** Rhodium element guide: atomic number 45, symbol Rh, atomic mass 102.91, electron configuration [Kr] 4d⁸ 5s¹, catalytic converters and uses. **Keywords:** rhodium element, rhodium atomic number, rhodium electron configuration, rhodium uses, rhodium isotopes, rhodium catalytic converter, rhodium plating, Wilkinson catalyst, rhodium price **Properties:** atomic mass 102.91 u; electron configuration [Kr] 4d⁸ 5s¹; state Solid; electronegativity 2.28 - **History:** Rhodium was discovered in 1803 by William Hyde Wollaston while studying crude platinum ores. It was named from the Greek rhodon, meaning rose, because some rhodium salts have a rose-red color. - **Isotopes:** Rhodium-103, 100%, The only stable naturally occurring isotope of rhodium. - **Compounds:** RhCl₃ (Rhodium(III) Chloride), Rh₂O₃ (Rhodium(III) Oxide), RhCl(PPh₃)₃ (Wilkinson’s Catalyst) - **Uses:** Three-way catalytic converters, especially for reducing nitrogen oxides; Rhodium plating on white gold, silver jewelry and reflective surfaces; Platinum-rhodium thermocouples for high-temperature measurement; Homogeneous catalysts such as Wilkinson’s catalyst; Electrical contacts and corrosion-resistant coatings - **Biology:** Rhodium has no known essential biological role. - **Interesting:** Rhodium is often one of the most expensive precious metals because production is limited and demand from catalytic converters is high. Most rhodium use is tied to automotive emission control. Rhodium-103 makes natural rhodium monoisotopic. Rhodium plating gives jewelry a bright, reflective, corrosion-resistant finish. - **Study notes:** Rhodium has atomic number 45 and belongs to group 9. Its electron configuration is [Kr] 4d⁸ 5s¹. Rhodium is a platinum-group metal and commonly forms Rh³⁺ compounds. Catalytic converters use rhodium especially for NOx reduction. - **FAQ:** What is the atomic number of rhodium? → The atomic number of rhodium is 45. | What is the electron configuration of rhodium? → Rhodium has the electron configuration [Kr] 4d⁸ 5s¹. | What is rhodium used for? → Rhodium is used in catalytic converters, jewelry plating, thermocouples, catalysts and corrosion-resistant electrical contacts. ### Palladium (Pd) — https://ferrumone.com/en/element/palladium Atom no: 46 | Transition Metal | Period 5, Group 10 **Title:** Palladium: Atomic Number, Uses and Isotopes **Description:** Palladium element guide: atomic number 46, symbol Pd, atomic mass 106.42, electron configuration [Kr] 4d¹⁰, catalytic converters and uses. **Keywords:** palladium element, palladium atomic number, palladium electron configuration, palladium uses, palladium isotopes, palladium catalytic converter, palladium cross coupling, Suzuki reaction palladium, palladium hydrogen absorption **Properties:** atomic mass 106.42 u; electron configuration [Kr] 4d¹⁰; state Solid; electronegativity 2.2 - **History:** Palladium was discovered in 1803 by William Hyde Wollaston and named after the asteroid Pallas, which had been discovered shortly before. - **Isotopes:** Palladium-102, About 1.0%, Stable isotope of palladium.; Palladium-104, About 11.1%, Stable isotope of palladium.; Palladium-105, About 22.3%, Stable isotope of palladium.; Palladium-106, About 27.3%, The most abundant stable isotope of palladium.; Palladium-108, About 26.5%, Stable isotope of palladium.; Palladium-110, About 11.7%, Stable isotope of palladium. - **Compounds:** PdCl₂ (Palladium(II) Chloride), Pd(OAc)₂ (Palladium(II) Acetate), Pd/C (Palladium on Carbon) - **Uses:** Catalytic converters for oxidizing carbon monoxide and hydrocarbons; Palladium-catalyzed cross-coupling reactions such as Suzuki, Heck and Negishi reactions; Hydrogen purification membranes and hydrogen storage research; Multilayer ceramic capacitors and electronic components; Dental alloys, jewelry and white gold alloys - **Biology:** Palladium has no known essential biological role. - **Interesting:** Palladium has the unusual electron configuration [Kr] 4d¹⁰, with no 5s electron in the ground-state notation used here. Suzuki, Heck and Negishi cross-coupling reactions earned the 2010 Nobel Prize in Chemistry. Palladium can absorb large amounts of hydrogen into its metal lattice. Palladium is one of the platinum-group metals and is important in emission control. - **Study notes:** Palladium has atomic number 46 and belongs to group 10. Its electron configuration is [Kr] 4d¹⁰. Common oxidation states include 0, +2 and +4. Palladium catalysts are central to carbon-carbon bond formation in organic synthesis. - **FAQ:** What is the atomic number of palladium? → The atomic number of palladium is 46. | What is the electron configuration of palladium? → Palladium has the electron configuration [Kr] 4d¹⁰. | What is palladium used for? → Palladium is used in catalytic converters, cross-coupling catalysts, electronics, hydrogen purification, dental alloys and jewelry. ### Silver (Ag) — https://ferrumone.com/en/element/silver Atom no: 47 | Transition Metal | Period 5, Group 11 **Title:** Silver: Atomic Number, Uses and Isotopes **Description:** Silver element guide: atomic number 47, symbol Ag, atomic mass 107.87, electron configuration [Kr] 4d¹⁰ 5s¹, conductivity, uses and isotopes. **Keywords:** silver element, silver atomic number, silver electron configuration, silver uses, silver isotopes, silver conductivity, silver symbol Ag, silver bromide photography, silver nitrate chloride test **Properties:** atomic mass 107.87 u; electron configuration [Kr] 4d¹⁰ 5s¹; state Solid; electronegativity 1.93 - **History:** Silver has been known since antiquity and was used for ornaments, coins and trade. Its symbol Ag comes from the Latin argentum. - **Isotopes:** Silver-107, About 51.8%, The slightly more abundant stable isotope of silver.; Silver-109, About 48.2%, Stable isotope of silver. - **Compounds:** AgNO₃ (Silver Nitrate), AgBr (Silver Bromide), AgCl (Silver Chloride), Ag₂O (Silver Oxide) - **Uses:** Electrical contacts, conductive pastes, solar-cell electrodes and electronics; Jewelry, silverware, coins and decorative objects; Silver mirrors and reflective coatings; Silver halides such as AgBr in traditional photography; Antimicrobial wound dressings, coatings and filters; Silver oxide batteries for small devices - **Biology:** Silver has no essential biological role. Ag⁺ ions and some silver materials have antimicrobial activity, but excessive exposure can cause argyria, a permanent gray-blue discoloration of skin and tissues. - **Interesting:** Silver is the best electrical conductor among the elements. The symbol Ag comes from argentum, the Latin name for silver. Silver bromide and related silver halides made film photography possible. Silver ions are antimicrobial, which explains many medical and water-treatment uses. - **Study notes:** Silver has atomic number 47 and belongs to group 11. Its electron configuration is [Kr] 4d¹⁰ 5s¹. Silver commonly forms Ag⁺ compounds. Ag⁺ forms characteristic precipitates with halide ions, such as AgCl, AgBr and AgI. - **FAQ:** What is the atomic number of silver? → The atomic number of silver is 47. | What is the electron configuration of silver? → Silver has the electron configuration [Kr] 4d¹⁰ 5s¹. | Why is the symbol for silver Ag? → The symbol Ag comes from argentum, the Latin name for silver. ### Cadmium (Cd) — https://ferrumone.com/en/element/cadmium Atom no: 48 | Transition Metal | Period 5, Group 12 **Title:** Cadmium: Atomic Number, Uses and Isotopes **Description:** Cadmium element guide: atomic number 48, symbol Cd, atomic mass 112.41, electron configuration [Kr] 4d¹⁰ 5s², toxicity, uses and isotopes. **Keywords:** cadmium element, cadmium atomic number, cadmium electron configuration, cadmium uses, cadmium isotopes, cadmium toxicity, nickel cadmium battery, cadmium telluride solar cell, itai itai disease **Properties:** atomic mass 112.41 u; electron configuration [Kr] 4d¹⁰ 5s²; state Solid; electronegativity 1.69 - **History:** Cadmium was discovered in 1817 by Friedrich Strohmeyer in zinc compounds. Its name comes from cadmia, an old name for zinc ore. - **Isotopes:** Cadmium-106, About 1.25%, Stable isotope of cadmium.; Cadmium-108, About 0.89%, Stable isotope of cadmium.; Cadmium-110, About 12.5%, Stable isotope of cadmium.; Cadmium-111, About 12.8%, Stable isotope used in NMR studies.; Cadmium-112, About 24.1%, Stable isotope of cadmium.; Cadmium-113, About 12.2%, t½=About 8.04 x 10¹⁵ years, Very long-lived radioactive isotope and strong neutron absorber.; Cadmium-114, About 28.7%, The most abundant cadmium isotope.; Cadmium-116, About 7.5%, Long-lived isotope studied in double beta decay research. - **Compounds:** CdS (Cadmium Sulfide), CdSe (Cadmium Selenide), CdTe (Cadmium Telluride), CdCl₂ (Cadmium Chloride) - **Uses:** Nickel-cadmium rechargeable batteries, now restricted or replaced in many applications; Cadmium sulfide and cadmium selenide pigments; Cadmium telluride thin-film solar cells; Neutron-absorbing control rods and shielding materials; Corrosion-resistant coatings in specialized aerospace and marine uses - **Biology:** Cadmium has no essential biological role. It is toxic, accumulates in the body and can damage kidneys and bones; cadmium compounds are important environmental health hazards. - **Interesting:** Cadmium is toxic and environmentally persistent, so many uses are restricted. CdTe is one of the most important commercial thin-film solar cell materials. Cadmium pigments can produce intense yellow, orange and red colors. Cadmium pollution caused itai-itai disease in Japan, a landmark environmental health case. - **Study notes:** Cadmium has atomic number 48 and belongs to group 12. Its electron configuration is [Kr] 4d¹⁰ 5s². Cadmium commonly forms Cd²⁺ compounds. Cadmium toxicity should not be confused with usefulness of sealed industrial products such as batteries or CdTe solar modules. - **FAQ:** What is the atomic number of cadmium? → The atomic number of cadmium is 48. | What is the electron configuration of cadmium? → Cadmium has the electron configuration [Kr] 4d¹⁰ 5s². | Is cadmium toxic? → Yes. Cadmium is toxic, can accumulate in the body and is associated with kidney, bone and cancer risks depending on exposure form and level. ### Indium (In) — https://ferrumone.com/en/element/indium Atom no: 49 | Post-Transition Metal | Period 5, Group 13 **Title:** Indium: Atomic Number, Uses and Isotopes **Description:** Indium element guide: atomic number 49, symbol In, atomic mass 114.82, electron configuration [Kr] 4d¹⁰ 5s² 5p¹, ITO, uses and isotopes. **Keywords:** indium element, indium atomic number, indium electron configuration, indium uses, indium isotopes, indium tin oxide, ITO touchscreen, indium phosphide, CIGS solar cell **Properties:** atomic mass 114.82 u; electron configuration [Kr] 4d¹⁰ 5s² 5p¹; state Solid; electronegativity 1.78 - **History:** Indium was discovered in 1863 by Ferdinand Reich and Hieronymus Theodor Richter using spectroscopy. Its name comes from the indigo-blue spectral line that revealed the new element. - **Isotopes:** Indium-113, About 4.3%, Stable isotope of indium.; Indium-115, About 95.7%, t½=About 4.4 x 10¹⁴ years, Very long-lived beta-emitting isotope that dominates natural indium. - **Compounds:** In₂O₃ (Indium(III) Oxide), InP (Indium Phosphide), InCl₃ (Indium(III) Chloride), Cu(In,Ga)Se₂ (CIGS Absorber) - **Uses:** Indium tin oxide transparent conductive coatings for touchscreens, LCDs and solar panels; Indium phosphide and indium gallium arsenide semiconductors for optoelectronics; Indium gallium nitride LEDs and laser diode materials; Low-melting alloys, solders and cryogenic seals; CIGS thin-film solar cell absorber materials - **Biology:** Indium has no known essential biological role. - **Interesting:** Indium tin oxide is transparent and electrically conductive, which makes modern touchscreens possible. Indium is often recovered as a byproduct of zinc mining. Indium metal can make a crackling sound when bent, similar to tin cry. Indium-115 is very long-lived and makes up most natural indium. - **Study notes:** Indium has atomic number 49 and belongs to group 13. Its electron configuration is [Kr] 4d¹⁰ 5s² 5p¹. Indium commonly forms +3 compounds, but +1 chemistry is also known. ITO means indium tin oxide and is a transparent conducting oxide. - **FAQ:** What is the atomic number of indium? → The atomic number of indium is 49. | What is the electron configuration of indium? → Indium has the electron configuration [Kr] 4d¹⁰ 5s² 5p¹. | What is indium used for? → Indium is used in indium tin oxide coatings, semiconductors, LEDs, low-melting alloys, solders and CIGS solar cells. ### Tin (Sn) — https://ferrumone.com/en/element/tin Atom no: 50 | Post-Transition Metal | Period 5, Group 14 **Title:** Tin: Atomic Number, Uses and Isotopes **Description:** Tin element guide: atomic number 50, symbol Sn, atomic mass 118.71, electron configuration [Kr] 4d¹⁰ 5s² 5p², allotropes, uses and isotopes. **Keywords:** tin element, tin atomic number, tin electron configuration, tin uses, tin isotopes, tin symbol Sn, tin allotropes, white tin gray tin, tin pest, lead free solder **Properties:** atomic mass 118.71 u; electron configuration [Kr] 4d¹⁰ 5s² 5p²; state Solid; electronegativity 1.96 - **History:** Tin has been known since antiquity and became historically important through bronze, an alloy of copper and tin that helped define the Bronze Age. Its symbol Sn comes from the Latin stannum. - **Isotopes:** Tin-112, About 0.97%, Stable isotope of tin.; Tin-114, About 0.66%, Stable isotope of tin.; Tin-115, About 0.34%, Stable isotope of tin.; Tin-116, About 14.5%, Stable isotope of tin.; Tin-117, About 7.7%, Stable isotope used in NMR studies.; Tin-118, About 24.2%, Stable isotope of tin.; Tin-119, About 8.6%, Stable isotope used in NMR and Mössbauer spectroscopy.; Tin-120, About 32.6%, The most abundant stable isotope of tin.; Tin-122, About 4.6%, Stable isotope of tin.; Tin-124, About 5.8%, Long-lived isotope studied in double beta decay research. - **Allotropes:** White Tin (β-Sn) (Metallic form stable above about 13.2 °C; the common useful form of tin.); Gray Tin (α-Sn) (Diamond-cubic semiconducting form favored below about 13.2 °C; associated with tin pest.) - **Compounds:** SnO₂ (Tin(IV) Oxide), SnCl₂ (Tin(II) Chloride), SnCl₄ (Tin(IV) Chloride), Sn-Ag-Cu (Tin-Silver-Copper Solder) - **Uses:** Tinplate coatings on steel cans for food packaging; Lead-free solder such as tin-silver-copper alloys in electronics; Bronze, the copper-tin alloy used in tools, bells, sculpture and bearings; Tin dioxide in transparent conducting films, gas sensors and ceramic glazes; Organotin compounds in PVC stabilizers and specialized chemistry, with restrictions on toxic biocides - **Biology:** Tin has no confirmed essential biological role in humans, though trace amounts occur in organisms. - **Interesting:** Tin has more stable isotopes than any other element. Tin pest is the transformation of white tin to gray tin at low temperatures, which can make metal crumble. Bronze is an alloy of copper and tin and was central to the Bronze Age. The symbol Sn comes from stannum, the Latin name for tin. - **Study notes:** Tin has atomic number 50 and belongs to group 14. Its electron configuration is [Kr] 4d¹⁰ 5s² 5p². Common oxidation states are +2 and +4. Tin allotropes must be distinguished from tin compounds such as SnO₂ or SnCl₂. - **FAQ:** What is the atomic number of tin? → The atomic number of tin is 50. | What is the electron configuration of tin? → Tin has the electron configuration [Kr] 4d¹⁰ 5s² 5p². | Why is the symbol for tin Sn? → The symbol Sn comes from stannum, the Latin name for tin. ### Antimony (Sb) — https://ferrumone.com/en/element/antimony Atom no: 51 | Metalloid | Period 5, Group 15 **Title:** Antimony: Atomic Number, Uses and Isotopes **Description:** Antimony element guide: atomic number 51, symbol Sb, atomic mass 121.76, electron configuration [Kr] 4d¹⁰ 5s² 5p³, flame retardants, alloys and isotopes. **Keywords:** antimony element, antimony atomic number, antimony electron configuration, antimony uses, antimony isotopes, antimony symbol Sb, antimony flame retardant, antimony trioxide, stibnite, GeSbTe phase change memory **Properties:** atomic mass 121.76 u; electron configuration [Kr] 4d¹⁰ 5s² 5p³; state Solid; electronegativity 2.05 - **History:** Antimony compounds have been known since antiquity, especially stibnite, Sb₂S₃, used as kohl eye cosmetic. Metallic antimony was described in detail by Nicolas Lémery in 1707, and the symbol Sb comes from the Latin stibium. - **Isotopes:** Antimony-121, About 57.2%, Stable and the more abundant natural antimony isotope.; Antimony-123, About 42.8%, Stable isotope of antimony. - **Allotropes:** Gray Antimony (Metallic, rhombohedral and the stable brittle metalloid form of antimony.); Yellow Antimony (Low-temperature molecular Sb₄ form that is unstable and converts to other forms.); Black Antimony (Amorphous form produced by condensation of antimony vapor; studied for semiconducting behavior.) - **Compounds:** Sb₂O₃ (Antimony(III) Oxide), Sb₂S₃ (Antimony(III) Sulfide (Stibnite)), SbCl₃ (Antimony(III) Chloride), GeSbTe (Germanium-Antimony-Tellurium Alloy) - **Uses:** Antimony trioxide as a synergist in halogenated flame-retardant plastics, textiles and electronics; Lead-antimony alloys for hard lead, battery grids and bearing metals; GeSbTe phase-change materials for rewritable optical discs and phase-change memory; Antimony-containing semiconductors and infrared detector materials; Tin-antimony solders, babbitt metals and specialty alloys - **Biology:** Antimony has no known essential biological role and many soluble antimony compounds are toxic at elevated exposure. - **Interesting:** Antimony uses the chemical symbol Sb from stibium, not from its English name. GeSbTe can switch between amorphous and crystalline states, changing electrical resistance for phase-change memory. Stibnite was used as kohl eye cosmetic in ancient Egypt and Mesopotamia. Natural antimony has two stable isotopes in a roughly 3:2 abundance ratio. - **Study notes:** Antimony has atomic number 51 and belongs to group 15. Its electron configuration is [Kr] 4d¹⁰ 5s² 5p³. Antimony is a metalloid; common oxidation states include +3, +5 and -3. For SEO and chemistry review, connect Sb₂O₃ with flame retardants and GeSbTe with phase-change memory. - **FAQ:** What is the atomic number of antimony? → The atomic number of antimony is 51. | What is the electron configuration of antimony? → Antimony has the electron configuration [Kr] 4d¹⁰ 5s² 5p³. | Why is the symbol for antimony Sb? → The symbol Sb comes from stibium, the Latin name associated with antimony sulfide. ### Tellurium (Te) — https://ferrumone.com/en/element/tellurium Atom no: 52 | Metalloid | Period 5, Group 16 **Title:** Tellurium: Atomic Number, Uses and Isotopes **Description:** Tellurium element guide: atomic number 52, symbol Te, atomic mass 127.60, electron configuration [Kr] 4d¹⁰ 5s² 5p⁴, CdTe solar cells and isotopes. **Keywords:** tellurium element, tellurium atomic number, tellurium electron configuration, tellurium uses, tellurium isotopes, cadmium telluride solar cells, bismuth telluride thermoelectric, tellurium breath, tellurium compounds **Properties:** atomic mass 127.6 u; electron configuration [Kr] 4d¹⁰ 5s² 5p⁴; state Solid; electronegativity 2.1 - **History:** Tellurium was discovered in 1782 by Franz-Joseph Müller von Reichenstein in Transylvanian gold ores. Martin Heinrich Klaproth later confirmed the discovery and named it after tellus, the Latin word for Earth. - **Isotopes:** Tellurium-120, About 0.09%, Rare stable isotope.; Tellurium-122, About 2.6%, Stable isotope of tellurium.; Tellurium-123, About 0.9%, Stable isotope used in NMR studies.; Tellurium-124, About 4.7%, Stable isotope of tellurium.; Tellurium-125, About 7.1%, NMR-active stable isotope.; Tellurium-126, About 18.8%, Stable isotope of tellurium.; Tellurium-128, About 31.7%, Very long-lived double beta decay isotope.; Tellurium-130, About 34.1%, Most abundant isotope; studied in double beta decay experiments. - **Allotropes:** Crystalline Tellurium (Silvery, trigonal, chain-structured and the most stable metalloid form.); Amorphous Tellurium (Dark powdery form that can convert to crystalline tellurium under light or heat.) - **Compounds:** CdTe (Cadmium Telluride), Bi₂Te₃ (Bismuth Telluride), TeO₂ (Tellurium Dioxide), H₂Te (Hydrogen Telluride) - **Uses:** Cadmium telluride thin-film solar cells; Bismuth telluride thermoelectric modules for Peltier cooling and waste-heat power generation; GeSbTe phase-change alloys for rewritable media and memory devices; Machinability additive in copper and steel alloys; Rubber vulcanization accelerators and specialty catalysts - **Biology:** Tellurium has no known essential biological role. Exposure to some tellurium compounds can produce dimethyl telluride in the body, causing a strong garlic-like odor known as tellurium breath. - **Interesting:** Tellurium breath is caused by volatile dimethyl telluride and can give breath a powerful garlic odor. Cadmium telluride solar cells use much less absorber material than conventional silicon wafers. Bismuth telluride is one of the classic room-temperature thermoelectric materials. Tellurium-128 has an extraordinarily long double beta decay half-life. - **Study notes:** Tellurium has atomic number 52 and belongs to group 16, the chalcogens. Its electron configuration is [Kr] 4d¹⁰ 5s² 5p⁴. Tellurium is a metalloid, while oxygen and sulfur in the same group are nonmetals. Remember CdTe for solar cells and Bi₂Te₃ for thermoelectric devices. - **FAQ:** What is the atomic number of tellurium? → The atomic number of tellurium is 52. | What is the electron configuration of tellurium? → Tellurium has the electron configuration [Kr] 4d¹⁰ 5s² 5p⁴. | What is tellurium used for? → Tellurium is used in CdTe solar cells, Bi₂Te₃ thermoelectrics, phase-change alloys, machinable copper alloys and rubber processing. ### Iodine (I) — https://ferrumone.com/en/element/iodine Atom no: 53 | Halogen | Period 5, Group 17 **Title:** Iodine: Atomic Number, Uses and Isotopes **Description:** Iodine element guide: atomic number 53, symbol I, atomic mass 126.90, electron configuration [Kr] 4d¹⁰ 5s² 5p⁵, thyroid role, iodized salt and iodine-131. **Keywords:** iodine element, iodine atomic number, iodine electron configuration, iodine uses, iodine isotopes, iodine thyroid, iodized salt, iodine 131, iodine starch test, povidone iodine **Properties:** atomic mass 126.9 u; electron configuration [Kr] 4d¹⁰ 5s² 5p⁵; state Solid; electronegativity 2.66 - **History:** Iodine was discovered in 1811 by Bernard Courtois while processing seaweed ash. Its name comes from the Greek ioeides, meaning violet-colored, because iodine vapor is violet. - **Isotopes:** Iodine-127, 100%, The only stable natural iodine isotope.; Iodine-123, t½=About 13.2 hours, Gamma-emitting isotope used in thyroid imaging.; Iodine-131, t½=About 8.0 days, Beta and gamma emitter used in thyroid therapy and important in nuclear fallout. - **Compounds:** KI (Potassium Iodide), I₂ (Molecular Iodine), NaIO₃ (Sodium Iodate), AgI (Silver Iodide) - **Uses:** Iodized salt for preventing iodine deficiency disorders; Povidone-iodine antiseptics for skin disinfection and wound care; Iodine-131 therapy for thyroid cancer and hyperthyroidism; Iodine-123 imaging for thyroid scans; Silver iodide for cloud seeding; Iodine-containing polarizing films in LCD displays - **Biology:** Iodine is an essential trace element. Thyroid hormones T₃ and T₄ contain iodine and regulate metabolism, growth and nervous-system development; deficiency can cause goiter and developmental problems. - **Interesting:** Iodine sublimes to a violet vapor when gently heated. Iodized salt is one of the most successful public-health interventions for preventing iodine deficiency. The iodine-starch test gives a dark blue-black color because polyiodide species fit inside starch helices. Potassium iodide tablets protect the thyroid by saturating it with stable iodine during certain nuclear incidents. - **Study notes:** Iodine has atomic number 53 and belongs to group 17, the halogens. Its electron configuration is [Kr] 4d¹⁰ 5s² 5p⁵. Iodine is a solid halogen at room temperature and forms violet vapor. Connect iodine with thyroid hormones, iodized salt, I-131 and the starch test. - **FAQ:** What is the atomic number of iodine? → The atomic number of iodine is 53. | What is the electron configuration of iodine? → Iodine has the electron configuration [Kr] 4d¹⁰ 5s² 5p⁵. | Why does the body need iodine? → The body needs iodine to make thyroid hormones T₃ and T₄, which regulate metabolism and development. ### Xenon (Xe) — https://ferrumone.com/en/element/xenon Atom no: 54 | Noble Gas | Period 5, Group 18 **Title:** Xenon: Atomic Number, Uses and Isotopes **Description:** Xenon element guide: atomic number 54, symbol Xe, atomic mass 131.29, electron configuration [Kr] 4d¹⁰ 5s² 5p⁶, noble gas compounds and ion propulsion. **Keywords:** xenon element, xenon atomic number, xenon electron configuration, xenon uses, xenon isotopes, xenon noble gas, xenon ion propulsion, xenon compounds, xenon 135 reactor poison, xenon difluoride **Properties:** atomic mass 131.29 u; electron configuration [Kr] 4d¹⁰ 5s² 5p⁶; state Gas; electronegativity 2.6 - **History:** Xenon was discovered in 1898 by William Ramsay and Morris Travers in the residue left after evaporating liquid air. Its name comes from the Greek xenos, meaning stranger or foreigner. - **Isotopes:** Xenon-124, About 0.095%, Very rare isotope studied for double electron capture.; Xenon-129, About 26.4%, NMR-active isotope used in hyperpolarized xenon MRI research.; Xenon-132, About 26.9%, The most abundant natural xenon isotope.; Xenon-136, About 8.9%, Used in double beta decay and dark matter research.; Xenon-135, t½=About 9.1 hours, Fission product with an extremely high neutron absorption cross section; a reactor poison. - **Compounds:** XeF₂ (Xenon Difluoride), XeF₄ (Xenon Tetrafluoride), XeO₃ (Xenon Trioxide) - **Uses:** Xenon arc lamps for cinema projection, searchlights and solar simulators; Xenon flash lamps for photography and laser pumping; Ion propulsion in spacecraft using Xe⁺ ions; Xenon difluoride for fluorination and silicon etching in microfabrication; Xenon radioisotopes for lung ventilation imaging and nuclear monitoring - **Biology:** Xenon has no known essential biological role. At high concentrations it can act as an anesthetic, partly through effects on NMDA receptors, but cost limits routine medical use. - **Interesting:** Xenon chemistry helped overturn the old idea that noble gases were completely inert. Xenon ion thrusters provide high fuel efficiency for long-duration spacecraft missions. Xenon-135 is called a reactor poison because it absorbs neutrons extremely strongly. Hyperpolarized xenon-129 can help image air spaces in the lungs. - **Study notes:** Xenon has atomic number 54 and closes period 5 as a group 18 noble gas. Its electron configuration is [Kr] 4d¹⁰ 5s² 5p⁶. Unlike lighter noble gases, xenon forms several stable compounds with fluorine and oxygen. Remember XeF₂ for silicon etching and Xe-135 for reactor poisoning. - **FAQ:** What is the atomic number of xenon? → The atomic number of xenon is 54. | What is the electron configuration of xenon? → Xenon has the electron configuration [Kr] 4d¹⁰ 5s² 5p⁶. | What is xenon used for? → Xenon is used in arc lamps, flash lamps, ion propulsion, specialized medical imaging, anesthesia research and xenon fluorides. ### Cesium (Cs) — https://ferrumone.com/en/element/cesium Atom no: 55 | Alkali Metal | Period 6, Group 1 **Title:** Cesium: Atomic Number, Uses and Isotopes **Description:** Cesium element guide: atomic number 55, symbol Cs, atomic mass 132.91, electron configuration [Xe] 6s¹, cesium atomic clocks, cesium-137 and uses. **Keywords:** cesium element, cesium atomic number, cesium electron configuration, cesium uses, cesium isotopes, cesium atomic clock, cesium 137, cesium symbol Cs, caesium element **Properties:** atomic mass 132.91 u; electron configuration [Xe] 6s¹; state Solid; electronegativity 0.79 - **History:** Cesium was discovered in 1860 by Robert Bunsen and Gustav Kirchhoff using spectroscopy. Its name comes from caesius, Latin for sky-blue, because of the blue spectral lines that revealed it. - **Isotopes:** Cesium-133, 100%, Only stable natural cesium isotope; used in the SI second definition.; Cesium-137, t½=About 30.1 years, Radioactive fission product and important long-lived fallout contaminant. - **Compounds:** CsCl (Cesium Chloride), CsI(Tl) (Thallium-Doped Cesium Iodide), Cs₂CO₃ (Cesium Carbonate), CsOH (Cesium Hydroxide) - **Uses:** Cesium atomic clocks that define the SI second through the hyperfine transition of cesium-133; Photoelectric cathodes and photomultiplier applications; Cesium-137 gamma sources for gauges, calibration and some older medical or industrial uses; Cesium iodide scintillation crystals for radiation detection; High-density cesium formate brines for oil and gas drilling fluids - **Biology:** Cesium has no essential biological role. Cs⁺ can behave somewhat like K⁺ in organisms, and radioactive cesium-137 can spread through soft tissues after nuclear contamination. - **Interesting:** The SI second is defined by 9,192,631,770 cycles of radiation from a cesium-133 hyperfine transition. Cesium melts just above room temperature, around 28.5 °C. Cesium reacts violently with water and must be stored away from air and moisture. Cesium-137 contamination became a major monitoring concern after nuclear accidents and weapons fallout. - **Study notes:** Cesium has atomic number 55 and belongs to group 1, the alkali metals. Its electron configuration is [Xe] 6s¹. Cesium commonly forms +1 compounds. For memory: Cs-133 defines the second, while Cs-137 is the fallout isotope. - **FAQ:** What is the atomic number of cesium? → The atomic number of cesium is 55. | What is the electron configuration of cesium? → Cesium has the electron configuration [Xe] 6s¹. | What is cesium used for? → Cesium is used in atomic clocks, photoelectric devices, radiation detectors, drilling fluids and specialized compounds. ### Barium (Ba) — https://ferrumone.com/en/element/barium Atom no: 56 | Alkaline Earth Metal | Period 6, Group 2 **Title:** Barium: Atomic Number, Uses and Isotopes **Description:** Barium element guide: atomic number 56, symbol Ba, atomic mass 137.33, electron configuration [Xe] 6s², barium sulfate contrast, green flame and isotopes. **Keywords:** barium element, barium atomic number, barium electron configuration, barium uses, barium isotopes, barium sulfate, barium X ray contrast, barium flame test, green fireworks, barium titanate **Properties:** atomic mass 137.33 u; electron configuration [Xe] 6s²; state Solid; electronegativity 0.89 - **History:** Carl Wilhelm Scheele identified barium minerals as containing a distinct substance in 1774, and Humphry Davy isolated metallic barium by electrolysis in 1808. The name comes from Greek barys, meaning heavy. - **Isotopes:** Barium-130, About 0.1%, Rare isotope studied in double beta decay context.; Barium-132, About 0.1%, Stable isotope of barium.; Barium-134, About 2.4%, Stable isotope of barium.; Barium-135, About 6.6%, Stable isotope, NMR active.; Barium-136, About 7.9%, Stable isotope of barium.; Barium-137, About 11.2%, Stable isotope; barium-137m is produced from cesium-137 decay.; Barium-138, About 71.7%, Most abundant stable barium isotope. - **Compounds:** BaSO₄ (Barium Sulfate), BaTiO₃ (Barium Titanate), Ba(NO₃)₂ (Barium Nitrate), BaCO₃ (Barium Carbonate) - **Uses:** Barium sulfate contrast suspensions for gastrointestinal X-ray imaging; Barite, BaSO₄, as a high-density drilling mud additive in oil and gas wells; Barium nitrate and barium chloride for green colors in fireworks; Barium titanate piezoelectric and dielectric ceramics; Barium sulfate as white pigment, filler and sulfate test precipitate - **Biology:** Barium has no essential biological role. Insoluble barium sulfate is safe enough for gastrointestinal X-ray contrast, but soluble barium salts are toxic because Ba²⁺ can disrupt potassium channels. - **Interesting:** Barium sulfate is useful medically precisely because it is extremely insoluble. Barium salts give a green flame, which makes barium important in fireworks. Barium titanate was one of the first major piezoelectric ceramics. The name barium refers to heavy minerals such as barite rather than unusually dense barium metal. - **Study notes:** Barium has atomic number 56 and belongs to group 2. Its electron configuration is [Xe] 6s². Barium commonly forms +2 compounds. BaSO₄ is insoluble and gives a white precipitate in sulfate tests. - **FAQ:** What is the atomic number of barium? → The atomic number of barium is 56. | What is the electron configuration of barium? → Barium has the electron configuration [Xe] 6s². | What is barium used for? → Barium is used in X-ray contrast materials, drilling mud, green fireworks, barium titanate ceramics and pigments. ### Lanthanum (La) — https://ferrumone.com/en/element/lanthanum Atom no: 57 | Lanthanide | Period 6, f-block **Title:** Lanthanum: Atomic Number, Uses and Isotopes **Description:** Lanthanum element guide: atomic number 57, symbol La, atomic mass 138.91, electron configuration [Xe] 5d¹ 6s², optical glass, NiMH batteries and isotopes. **Keywords:** lanthanum element, lanthanum atomic number, lanthanum electron configuration, lanthanum uses, lanthanum isotopes, rare earth element, lanthanum optical glass, lanthanum NiMH battery, lanthanum carbonate **Properties:** atomic mass 138.91 u; electron configuration [Xe] 5d¹ 6s²; state Solid; electronegativity 1.1 - **History:** Lanthanum was discovered in 1839 by Carl Gustaf Mosander while studying cerium compounds. Its name comes from the Greek lanthanein, meaning to lie hidden, because it had been hidden within cerium minerals. - **Isotopes:** Lanthanum-138, About 0.09%, t½=About 1.06 x 10¹¹ years, Very long-lived radioactive isotope.; Lanthanum-139, About 99.91%, Dominant stable isotope of lanthanum. - **Compounds:** La₂O₃ (Lanthanum Oxide), LaNi₅ (Lanthanum Nickel Alloy), LaCl₃ (Lanthanum(III) Chloride), La₂(CO₃)₃ (Lanthanum Carbonate) - **Uses:** Lanthanum oxide in high-refractive-index optical glass for camera and microscope lenses; Lanthanum-nickel alloys and mischmetal in nickel-metal hydride batteries; Fluid catalytic cracking catalysts in petroleum refining; Mischmetal for lighter flints and pyrophoric alloys; Lanthanum carbonate phosphate binder medicine - **Biology:** Lanthanum has no essential biological role. Lanthanum carbonate is used as a phosphate binder for some dialysis patients to reduce blood phosphate levels. - **Interesting:** Lanthanum gives its name to the lanthanide series even though its exact group-3 classification is sometimes discussed. LaNi₅ can reversibly absorb large amounts of hydrogen, which helped battery and hydrogen-storage research. Mischmetal is a commercial rare-earth mixture rich in cerium and lanthanum. Lanthanum oxide helps produce optical glass with high refractive index and low dispersion. - **Study notes:** Lanthanum has atomic number 57 and electron configuration [Xe] 5d¹ 6s². Lanthanum is commonly treated as the first lanthanide or as a group 3 element depending on table style. The common oxidation state is +3. Remember La₂O₃ for optical glass and LaNi₅ for hydrogen storage and NiMH batteries. - **FAQ:** What is the atomic number of lanthanum? → The atomic number of lanthanum is 57. | What is the electron configuration of lanthanum? → Lanthanum has the electron configuration [Xe] 5d¹ 6s². | What is lanthanum used for? → Lanthanum is used in optical glass, NiMH batteries, petroleum refining catalysts, mischmetal and lanthanum carbonate medicine. ### Cerium (Ce) — https://ferrumone.com/en/element/cerium Atom no: 58 | Lanthanide | Period 6, f-block **Title:** Cerium: Atomic Number, Uses and Isotopes **Description:** Cerium element guide: atomic number 58, symbol Ce, atomic mass 140.12, electron configuration [Xe] 4f¹ 5d¹ 6s², cerium oxide, catalysts and isotopes. **Keywords:** cerium element, cerium atomic number, cerium electron configuration, cerium uses, cerium isotopes, cerium oxide, cerium dioxide, catalytic converter oxygen storage, rare earth polishing powder **Properties:** atomic mass 140.12 u; electron configuration [Xe] 4f¹ 5d¹ 6s²; state Solid; electronegativity 1.12 - **History:** Cerium was discovered in 1803 by Jöns Jacob Berzelius and Wilhelm Hisinger, and independently by Martin Heinrich Klaproth. It was named after Ceres, the dwarf planet discovered shortly before. - **Isotopes:** Cerium-136, About 0.19%, Rare isotope studied in double beta decay context.; Cerium-138, About 0.25%, Stable isotope of cerium.; Cerium-140, About 88.5%, Dominant natural cerium isotope.; Cerium-142, About 11.1%, Long-lived isotope studied for double beta decay. - **Compounds:** CeO₂ (Cerium(IV) Oxide), Ce₂O₃ (Cerium(III) Oxide), Ce(NH₄)₂(NO₃)₆ (Cerium Ammonium Nitrate), Ce₂(SO₄)₃ (Cerium(III) Sulfate) - **Uses:** Cerium dioxide polishing powders for optical glass, lenses and display glass; Oxygen-storage component in automotive catalytic converters; Mischmetal for lighter flints and pyrophoric alloys; Self-cleaning oven coatings and catalytic surfaces; Cerium ammonium nitrate as a one-electron oxidant in organic chemistry - **Biology:** Cerium has no known essential biological role. Cerium oxide nanoparticles are studied because the Ce³⁺/Ce⁴⁺ redox cycle can interact with reactive oxygen species. - **Interesting:** Cerium is more abundant in Earth’s crust than some familiar metals such as copper. CeO₂ works as an oxygen buffer because cerium can switch between +3 and +4 oxidation states. Cerium oxide polishing is used for high-quality optical and display glass finishing. Cerium is a major component of mischmetal, the sparking alloy used in lighter flints. - **Study notes:** Cerium has atomic number 58 and electron configuration [Xe] 4f¹ 5d¹ 6s². Unlike many lanthanides, cerium commonly shows both +3 and +4 oxidation states. CeO₂ is cerium dioxide and is central to polishing and catalytic converter chemistry. Cerium is the most abundant lanthanide. - **FAQ:** What is the atomic number of cerium? → The atomic number of cerium is 58. | What is the electron configuration of cerium? → Cerium has the electron configuration [Xe] 4f¹ 5d¹ 6s². | What is cerium used for? → Cerium is used in glass polishing powders, catalytic converters, mischmetal, self-cleaning ovens and oxidation chemistry. ### Praseodymium (Pr) — https://ferrumone.com/en/element/praseodymium Atom no: 59 | Lanthanide | Period 6, f-block **Title:** Praseodymium: Atomic Number, Uses and Isotopes **Description:** Praseodymium element guide: atomic number 59, symbol Pr, atomic mass 140.91, electron configuration [Xe] 4f³ 6s², magnets, pigments and isotopes. **Keywords:** praseodymium element, praseodymium atomic number, praseodymium electron configuration, praseodymium uses, praseodymium isotopes, praseodymium magnets, praseodymium yellow pigment, didymium glass, rare earth element **Properties:** atomic mass 140.91 u; electron configuration [Xe] 4f³ 6s²; state Solid; electronegativity 1.13 - **History:** Praseodymium was separated in 1885 by Carl Auer von Welsbach from didymium, which was once thought to be a single element. Its name comes from Greek words meaning green twin, referring to its green salts and its relationship with neodymium. - **Isotopes:** Praseodymium-141, 100%, The only stable natural praseodymium isotope. - **Compounds:** Pr₆O₁₁ (Praseodymium Oxide), PrCl₃ (Praseodymium(III) Chloride), PrFeB (Praseodymium-Iron-Boron Alloy) - **Uses:** Praseodymium additions to Nd-Fe-B rare earth magnets to improve performance and corrosion behavior; Praseodymium oxide yellow-orange pigments for ceramics and glass; Didymium glass with neodymium for filtering intense yellow sodium light; High-strength magnesium alloys for aircraft-engine applications; Specialty optical and magneto-optic materials - **Biology:** Praseodymium has no known essential biological role. - **Interesting:** Praseodymium and neodymium were both separated from didymium, the old “twin” rare earth mixture. Praseodymium salts often show green colors, matching the origin of the element’s name. Praseodymium yellow pigments are valued as lower-toxicity alternatives to some older heavy-metal pigments. Natural praseodymium is monoisotopic, consisting of praseodymium-141. - **Study notes:** Praseodymium has atomic number 59 and is a lanthanide. Its electron configuration is [Xe] 4f³ 6s². The most common oxidation state is +3. Remember Pr for rare earth magnets, pigments and didymium glass. - **FAQ:** What is the atomic number of praseodymium? → The atomic number of praseodymium is 59. | What is the electron configuration of praseodymium? → Praseodymium has the electron configuration [Xe] 4f³ 6s². | What is praseodymium used for? → Praseodymium is used in rare earth magnets, ceramic pigments, colored glass, didymium glass and specialty alloys. ### Elements 60–118 (Neodymium–Oganesson) ### Neodymium (Nd) — https://ferrumone.com/en/element/neodymium Atom no: 60 | Lanthanide | Period 6, f-block **Title:** Neodymium: Atomic Number, Uses and Isotopes **Description:** Neodymium element guide: atomic number 60, symbol Nd, atomic mass 144.24, electron configuration [Xe] 4f⁴ 6s², neodymium magnets, Nd:YAG lasers and isotopes. **Keywords:** neodymium element, neodymium atomic number, neodymium electron configuration, neodymium uses, neodymium isotopes, neodymium magnets, NdFeB magnet, Nd:YAG laser, rare earth magnets, neodymium glass **Properties:** atomic mass 144.24 u; electron configuration [Xe] 4f⁴ 6s²; state Solid; electronegativity 1.14 - **History:** Neodymium was separated from didymium in 1885 by Carl Auer von Welsbach along with praseodymium. Its name means new twin, reflecting its separation from the old didymium rare earth mixture. - **Isotopes:** Neodymium-142, About 27.2%, Most abundant stable neodymium isotope.; Neodymium-143, About 12.2%, Daughter isotope in the samarium-neodymium dating system.; Neodymium-144, About 23.8%, t½=About 2.29 x 10¹⁵ years, Very long-lived alpha-emitting isotope.; Neodymium-145, About 8.3%, Stable isotope of neodymium.; Neodymium-146, About 17.2%, Stable isotope of neodymium.; Neodymium-148, About 5.8%, Stable isotope of neodymium.; Neodymium-150, About 5.6%, Studied in double beta decay research. - **Compounds:** Nd₂Fe₁₄B (Neodymium-Iron-Boron), Nd:YAG (Neodymium-Doped Yttrium Aluminum Garnet), Nd₂O₃ (Neodymium Oxide), NdCl₃ (Neodymium(III) Chloride) - **Uses:** Nd₂Fe₁₄B permanent magnets for electric motors, wind turbines, hard drives, speakers and headphones; Nd:YAG solid-state lasers at 1064 nm for surgery, manufacturing, range finding and research; Neodymium-doped glass for high-energy laser systems; Neodymium oxide glass colorants that give violet or reddish-purple colors; Rare earth magnet supply chains for electric vehicles and clean-energy technologies - **Biology:** Neodymium has no known essential biological role. - **Interesting:** Nd-Fe-B magnets have extremely high magnetic energy density and are central to compact electric motors. Large wind turbines and electric vehicles can require significant amounts of neodymium-containing magnets. Nd:YAG lasers are among the most common solid-state lasers in medicine and industry. Neodymium glass can appear different colors under different lighting because of its sharp absorption bands. - **Study notes:** Neodymium has atomic number 60 and is a lanthanide. Its electron configuration is [Xe] 4f⁴ 6s². The common oxidation state is +3. Remember Nd₂Fe₁₄B for strong magnets and Nd:YAG for lasers. - **FAQ:** What is the atomic number of neodymium? → The atomic number of neodymium is 60. | What is the electron configuration of neodymium? → Neodymium has the electron configuration [Xe] 4f⁴ 6s². | What is neodymium used for? → Neodymium is used in powerful permanent magnets, Nd:YAG lasers, laser glass, colored glass and clean-energy technologies. ### Promethium (Pm) — https://ferrumone.com/en/element/promethium Atom no: 61 | Lanthanide | Period 6, f-block **Title:** Promethium: Atomic Number, Uses and Isotopes **Description:** Promethium element guide: atomic number 61, symbol Pm, atomic mass 145, electron configuration [Xe] 4f⁵ 6s², radioactive isotopes, promethium-147 and uses. **Keywords:** promethium element, promethium atomic number, promethium electron configuration, promethium uses, promethium isotopes, promethium 147, radioactive lanthanide, promethium no stable isotopes, promethium nuclear battery **Properties:** atomic mass 145 u; electron configuration [Xe] 4f⁵ 6s²; state Solid; electronegativity 1.13 - **History:** Promethium was identified in 1945 by Jacob A. Marinsky, Lawrence E. Glendenin and Charles D. Coryell while separating uranium fission products at Oak Ridge. Its name comes from Prometheus, the Titan who stole fire for humanity. - **Isotopes:** Promethium-145, t½=About 17.7 years, One of the longest-lived promethium isotopes; decays mainly by electron capture.; Promethium-146, t½=About 5.5 years, Radioactive isotope used in research context.; Promethium-147, t½=About 2.623 years, Beta-emitting isotope and the main practical promethium isotope. - **Compounds:** Pm₂O₃ (Promethium(III) Oxide), PmCl₃ (Promethium(III) Chloride) - **Uses:** Promethium-147 beta sources for thickness gauges and specialized industrial measurement; Historic nuclear battery and luminous paint research, now limited by radioactivity and availability; Portable X-ray and radiation-source research using promethium radioisotopes; Scientific studies of radioactive lanthanide chemistry and beta-emitting materials - **Biology:** Promethium has no biological role. All promethium isotopes are radioactive, so biological exposure is treated as a radiological hazard rather than as normal trace-element chemistry. - **Interesting:** Promethium and technetium are the only elements below bismuth with no stable isotopes. Natural promethium exists only in extremely tiny amounts from uranium and thorium decay or fission processes. Promethium-147 is a beta emitter, which made it attractive for thickness gauges and experimental nuclear batteries. The Prometheus name fits an element tied to nuclear energy and artificial production. - **Study notes:** Promethium has atomic number 61 and is a lanthanide. Its electron configuration is [Xe] 4f⁵ 6s². Promethium has no stable isotopes; this is the key exam and reference fact. Connect Pm-147 with beta sources, thickness gauges and historical nuclear battery ideas. - **FAQ:** What is the atomic number of promethium? → The atomic number of promethium is 61. | What is the electron configuration of promethium? → Promethium has the electron configuration [Xe] 4f⁵ 6s². | Does promethium have stable isotopes? → No. All promethium isotopes are radioactive. ### Samarium (Sm) — https://ferrumone.com/en/element/samarium Atom no: 62 | Lanthanide | Period 6, f-block **Title:** Samarium: Atomic Number, Uses and Isotopes **Description:** Samarium element guide: atomic number 62, symbol Sm, atomic mass 150.36, electron configuration [Xe] 4f⁶ 6s², SmCo magnets, samarium-153 and isotopes. **Keywords:** samarium element, samarium atomic number, samarium electron configuration, samarium uses, samarium isotopes, samarium cobalt magnets, samarium 153 EDTMP, samarium iodide, Sm-Nd dating **Properties:** atomic mass 150.36 u; electron configuration [Xe] 4f⁶ 6s²; state Solid; electronegativity 1.17 - **History:** Samarium was isolated in 1879 by Paul Émile Lecoq de Boisbaudran from the mineral samarskite. The mineral name honors Vasili Samarsky-Bykhovets, making samarium one of the first elements named through a person’s name. - **Isotopes:** Samarium-144, About 3.1%, Stable isotope of samarium.; Samarium-147, About 15.0%, t½=About 1.06 x 10¹¹ years, Alpha-emitting isotope used in Sm-Nd dating.; Samarium-148, About 11.2%, t½=About 6.3 x 10¹⁵ years, Extremely long-lived alpha-emitting isotope of samarium.; Samarium-149, About 13.8%, Very strong neutron absorber important in reactor physics.; Samarium-150, About 7.4%, Stable isotope of samarium.; Samarium-152, About 26.7%, Most abundant natural samarium isotope.; Samarium-153, t½=About 46 hours, Beta-emitting medical radioisotope used in Sm-EDTMP.; Samarium-154, About 22.7%, Stable isotope of samarium. - **Compounds:** SmCo₅ (Samarium-Cobalt Magnet), SmI₂ (Samarium(II) Iodide), Sm₂O₃ (Samarium(III) Oxide), Sm-EDTMP (Samarium-153 EDTMP) - **Uses:** Samarium-cobalt permanent magnets for high-temperature motors, aerospace and defense systems; Samarium-153 EDTMP radiopharmaceuticals for bone metastasis pain palliation; Samarium(II) iodide, SmI₂, as a one-electron reducing reagent in organic synthesis; Neutron absorption in nuclear reactor materials and samarium oxide control applications; Sm-Nd isotope dating for ancient rocks, meteorites and lunar samples - **Biology:** Samarium has no essential biological role. Samarium-153 EDTMP has been used as a radiopharmaceutical for pain from bone metastases. - **Interesting:** Samarium-cobalt magnets keep useful magnetic performance at temperatures where many Nd-Fe-B magnets weaken. Samarium-149 is a nuclear reactor poison because it strongly absorbs neutrons. SmI₂ is famous in organic synthesis for enabling single-electron reductions and carbon-carbon bond formation. The Sm-Nd dating system helps determine ages of very old rocks and meteorites. - **Study notes:** Samarium has atomic number 62 and is a lanthanide. Its electron configuration is [Xe] 4f⁶ 6s². Common samarium chemistry is dominated by +3, but +2 chemistry is important in SmI₂. Remember SmCo magnets, Sm-153 medicine, SmI₂ reagent and Sm-Nd dating. - **FAQ:** What is the atomic number of samarium? → The atomic number of samarium is 62. | What is the electron configuration of samarium? → Samarium has the electron configuration [Xe] 4f⁶ 6s². | What is samarium used for? → Samarium is used in samarium-cobalt magnets, neutron absorbers, SmI₂ synthesis chemistry, Sm-153 radiopharmaceuticals and isotope dating. ### Europium (Eu) — https://ferrumone.com/en/element/europium Atom no: 63 | Lanthanide | Period 6, f-block **Title:** Europium: Atomic Number, Uses and Isotopes **Description:** Europium element guide: atomic number 63, symbol Eu, atomic mass 151.96, electron configuration [Xe] 4f⁷ 6s², europium phosphors, banknotes and isotopes. **Keywords:** europium element, europium atomic number, europium electron configuration, europium uses, europium isotopes, europium phosphor, europium red phosphor, euro banknote fluorescence, Eu2+ Eu3+ **Properties:** atomic mass 151.96 u; electron configuration [Xe] 4f⁷ 6s²; state Solid; electronegativity 1.2 - **History:** Europium was isolated by Eugène-Anatole Demarçay in 1901 after he recognized it as a separate component in samarium materials. It was named after Europe. - **Isotopes:** Europium-151, About 47.8%, t½=About 4.6 x 10¹⁸ years, Extremely long-lived alpha-emitting isotope, often treated as stable for practical chemistry.; Europium-153, About 52.2%, Stable and slightly more abundant natural europium isotope. - **Compounds:** Y₂O₃:Eu³⁺ (Europium-Doped Yttrium Oxide), BaMgAl₁₀O₁₇:Eu²⁺ (BAM:Eu²⁺), EuO (Europium(II) Oxide), Eu-DTPA (Europium Chelate) - **Uses:** Europium(III) red phosphors in displays, fluorescent lamps and white LEDs; Europium(II) blue phosphors in lighting and display materials; Anti-counterfeiting fluorescence features in euro banknotes and security inks; Time-resolved fluorescence labels in biological and medical assays; Research in redox chemistry because europium can access +2 and +3 states - **Biology:** Europium has no essential biological role. Europium chelate complexes are useful as long-lived fluorescent labels in biochemical assays. - **Interesting:** Europium gives some security documents a hidden red fluorescence under ultraviolet light. Eu³⁺ red emission around 611 nm was crucial for color display and lamp phosphor technology. Europium is unusual among lanthanides because Eu²⁺ is relatively accessible and stable. The half-filled 4f⁷ arrangement helps explain europium’s distinctive redox behavior. - **Study notes:** Europium has atomic number 63 and is a lanthanide. Its electron configuration is [Xe] 4f⁷ 6s². Europium commonly shows +2 and +3 oxidation states. Remember europium for red phosphors, blue phosphors and banknote fluorescence. - **FAQ:** What is the atomic number of europium? → The atomic number of europium is 63. | What is the electron configuration of europium? → Europium has the electron configuration [Xe] 4f⁷ 6s². | What is europium used for? → Europium is used in red and blue phosphors, security printing, fluorescence labels, displays and lighting. ### Gadolinium (Gd) — https://ferrumone.com/en/element/gadolinium Atom no: 64 | Lanthanide | Period 6, f-block **Title:** Gadolinium: Atomic Number, Uses and Isotopes **Description:** Gadolinium element guide: atomic number 64, symbol Gd, atomic mass 157.25, electron configuration [Xe] 4f⁷ 5d¹ 6s², MRI contrast and isotopes. **Keywords:** gadolinium element, gadolinium atomic number, gadolinium electron configuration, gadolinium uses, gadolinium isotopes, gadolinium MRI contrast, gadolinium 157, neutron absorption, magnetocaloric effect **Properties:** atomic mass 157.25 u; electron configuration [Xe] 4f⁷ 5d¹ 6s²; state Solid; electronegativity 1.2 - **History:** Gadolinium was detected by Jean Charles Galissard de Marignac in 1880 and later isolated by Paul Émile Lecoq de Boisbaudran. It is named after Johan Gadolin, whose work helped launch rare earth chemistry. - **Isotopes:** Gadolinium-152, About 0.2%, Rare natural gadolinium isotope.; Gadolinium-154, About 2.2%, Stable isotope of gadolinium.; Gadolinium-155, About 14.8%, Very high thermal neutron absorption cross section.; Gadolinium-156, About 20.5%, Stable isotope of gadolinium.; Gadolinium-157, About 15.7%, One of the strongest known thermal neutron absorbers.; Gadolinium-158, About 24.8%, Most abundant natural gadolinium isotope.; Gadolinium-160, About 21.9%, Stable isotope of gadolinium. - **Compounds:** Gd-DTPA (Gadolinium DTPA), Gd-DOTA (Gadolinium DOTA), Gd₂O₃ (Gadolinium(III) Oxide), Gd₃Ga₅O₁₂ (Gadolinium Gallium Garnet) - **Uses:** Chelated gadolinium MRI contrast agents for medical imaging; Gadolinium isotopes as neutron absorbers and burnable poisons in nuclear reactors; Magnetocaloric cooling research near room temperature; Gadolinium gallium garnet substrates and magneto-optic materials; Alloy additions for magnetic and electronic materials - **Biology:** Gadolinium has no essential biological role. Free Gd³⁺ is toxic, so medical MRI agents use chelates designed to hold gadolinium tightly and help the body excrete it. - **Interesting:** Gd³⁺ has seven unpaired 4f electrons, giving it strong paramagnetism useful in MRI contrast. Gadolinium-157 has an exceptionally large neutron capture cross section. Gadolinium metal has a Curie temperature near room temperature, making it important in magnetocaloric research. Gadolinium’s electron configuration includes a 5d electron because the half-filled 4f⁷ arrangement is especially stable. - **Study notes:** Gadolinium has atomic number 64 and is a lanthanide. Its electron configuration is [Xe] 4f⁷ 5d¹ 6s². Gd³⁺ is highly paramagnetic because of seven unpaired f electrons. Remember gadolinium for MRI contrast and neutron absorption. - **FAQ:** What is the atomic number of gadolinium? → The atomic number of gadolinium is 64. | What is the electron configuration of gadolinium? → Gadolinium has the electron configuration [Xe] 4f⁷ 5d¹ 6s². | What is gadolinium used for? → Gadolinium is used in MRI contrast agents, neutron absorbers, magnetocaloric research and magneto-optic materials. ### Terbium (Tb) — https://ferrumone.com/en/element/terbium Atom no: 65 | Lanthanide | Period 6, f-block **Title:** Terbium: Atomic Number, Uses and Isotopes **Description:** Terbium element guide: atomic number 65, symbol Tb, atomic mass 158.93, electron configuration [Xe] 4f⁹ 6s², green phosphors, Terfenol-D and isotopes. **Keywords:** terbium element, terbium atomic number, terbium electron configuration, terbium uses, terbium isotopes, terbium green phosphor, Terfenol-D, terbium magnetostriction, rare earth phosphor **Properties:** atomic mass 158.93 u; electron configuration [Xe] 4f⁹ 6s²; state Solid; electronegativity 1.2 - **History:** Terbium was discovered by Carl Gustaf Mosander in 1843 while studying yttria fractions. It is named after Ytterby, the Swedish village that also gave names to yttrium, erbium and ytterbium. - **Isotopes:** Terbium-159, 100%, The only stable natural terbium isotope. - **Compounds:** Tb₄O₇ (Terbium Oxide), LaPO₄:Ce,Tb (Cerium-Terbium Doped Lanthanum Phosphate), Tb₀.₃Dy₀.₇Fe₂ (Terfenol-D) - **Uses:** Terbium-doped green phosphors for fluorescent lamps, displays and efficient lighting; Terfenol-D magnetostrictive alloy for sonar transducers, sensors and actuators; Terbium additions to rare earth magnets for higher coercivity and high-temperature performance; Terbium-doped glass in Faraday rotators and optical isolator components; Time-resolved fluorescence labels in biochemical assays - **Biology:** Terbium has no essential biological role. Terbium fluorescence is useful in biochemical labeling and time-resolved assays. - **Interesting:** Terfenol-D can change shape in a magnetic field far more than ordinary metals, making it useful for precision actuators. Tb³⁺ emission gives a strong green color used in phosphor technology. Terbium is monoisotopic: natural terbium is essentially all terbium-159. The name Terfenol-D combines terbium, iron, Naval Ordnance Laboratory and dysprosium. - **Study notes:** Terbium has atomic number 65 and is a lanthanide. Its electron configuration is [Xe] 4f⁹ 6s². The common oxidation state is +3, though +4 chemistry exists in some compounds. Remember terbium for green phosphors and Terfenol-D magnetostriction. - **FAQ:** What is the atomic number of terbium? → The atomic number of terbium is 65. | What is the electron configuration of terbium? → Terbium has the electron configuration [Xe] 4f⁹ 6s². | What is terbium used for? → Terbium is used in green phosphors, Terfenol-D, rare earth magnets, optical isolators and fluorescence labels. ### Dysprosium (Dy) — https://ferrumone.com/en/element/dysprosium Atom no: 66 | Lanthanide | Period 6, f-block **Title:** Dysprosium: Atomic Number, Uses and Isotopes **Description:** Dysprosium element guide: atomic number 66, symbol Dy, atomic mass 162.50, electron configuration [Xe] 4f¹⁰ 6s², EV magnets, Terfenol-D and isotopes. **Keywords:** dysprosium element, dysprosium atomic number, dysprosium electron configuration, dysprosium uses, dysprosium isotopes, dysprosium magnets, dysprosium EV motors, NdFeB high temperature magnet, Terfenol-D dysprosium **Properties:** atomic mass 162.5 u; electron configuration [Xe] 4f¹⁰ 6s²; state Solid; electronegativity 1.22 - **History:** Dysprosium was discovered in 1886 by Paul Émile Lecoq de Boisbaudran. Its name comes from the Greek dysprositos, meaning hard to get, because it was very difficult to separate from other rare earths. - **Isotopes:** Dysprosium-156, About 0.06%, Rare stable isotope.; Dysprosium-158, About 0.10%, Rare stable isotope of dysprosium.; Dysprosium-160, About 2.3%, Stable isotope of dysprosium.; Dysprosium-161, About 18.9%, Stable isotope of dysprosium.; Dysprosium-162, About 25.5%, Stable isotope of dysprosium.; Dysprosium-163, About 24.9%, Stable isotope of dysprosium.; Dysprosium-164, About 28.3%, Most abundant natural dysprosium isotope. - **Compounds:** Dy₂O₃ (Dysprosium(III) Oxide), DyFe₂ (Dysprosium-Iron Compound), Tb₀.₃Dy₀.₇Fe₂ (Terfenol-D), DyI₃ (Dysprosium Iodide) - **Uses:** Dysprosium additions to Nd-Fe-B magnets for high-temperature electric vehicle motors and wind turbine generators; Terfenol-D magnetostrictive alloy with terbium and iron; Dysprosium oxide-nickel materials and other neutron absorbers for reactor control; Dysprosium iodide in high-intensity discharge lamps; Magneto-optic recording materials and specialized magnetic research - **Biology:** Dysprosium has no known essential biological role. - **Interesting:** Dysprosium is one of the hidden critical materials behind high-performance electric vehicle motors. Small dysprosium additions can help Nd-Fe-B magnets resist demagnetization at high operating temperatures. The name dysprosium literally points to how difficult it was to obtain in pure form. Dysprosium contributes to Terfenol-D, one of the best-known giant magnetostrictive materials. - **Study notes:** Dysprosium has atomic number 66 and is a lanthanide. Its electron configuration is [Xe] 4f¹⁰ 6s². The common oxidation state is +3. Remember dysprosium for EV motor magnets, wind turbines and neutron absorption. - **FAQ:** What is the atomic number of dysprosium? → The atomic number of dysprosium is 66. | What is the electron configuration of dysprosium? → Dysprosium has the electron configuration [Xe] 4f¹⁰ 6s². | What is dysprosium used for? → Dysprosium is used in high-temperature rare earth magnets, Terfenol-D, reactor control materials, discharge lamps and magneto-optic materials. ### Holmium (Ho) — https://ferrumone.com/en/element/holmium Atom no: 67 | Lanthanide | Period 6, f-block **Title:** Holmium: Atomic Number, Uses and Isotopes **Description:** Holmium element guide: atomic number 67, symbol Ho, atomic mass 164.93, electron configuration [Xe] 4f¹¹ 6s², Ho:YAG lasers, magnetic properties and isotopes. **Keywords:** holmium element, holmium atomic number, holmium electron configuration, holmium uses, holmium isotopes, Ho:YAG laser, holmium laser lithotripsy, holmium magnetic moment, holmium 165 **Properties:** atomic mass 164.93 u; electron configuration [Xe] 4f¹¹ 6s²; state Solid; electronegativity 1.23 - **History:** Holmium was discovered in 1878 in rare earth fractions associated with Ytterby minerals. Per Teodor Cleve named it after Holmia, the Latin name for Stockholm. - **Isotopes:** Holmium-165, 100%, The only stable natural holmium isotope. - **Compounds:** Ho₂O₃ (Holmium(III) Oxide), Ho:YAG (Holmium-Doped YAG), HoCl₃ (Holmium(III) Chloride) - **Uses:** Ho:YAG lasers for urinary stone lithotripsy, prostate surgery and precise tissue cutting; Holmium oxide and holmium compounds as neutron absorbers in reactor control materials; Magnetic materials research because holmium has very strong magnetic properties; Holmium-doped garnets and crystals in specialized lasers and microwave devices; Calibration and spectroscopy applications using holmium oxide glass filters - **Biology:** Holmium has no known essential biological role and is generally studied as a rare earth material rather than a biological element. - **Interesting:** Ho:YAG lasers are widely used in urology for fragmenting kidney and urinary stones. Holmium is often cited among the elements with the strongest magnetic moments. Natural holmium is monoisotopic, consisting of holmium-165. The name Holmium preserves the Latin name for Stockholm. - **Study notes:** Holmium has atomic number 67 and is a lanthanide. Its electron configuration is [Xe] 4f¹¹ 6s². The common oxidation state is +3. Remember Ho:YAG laser for lithotripsy and holmium-165 for monoisotopic natural holmium. - **FAQ:** What is the atomic number of holmium? → The atomic number of holmium is 67. | What is the electron configuration of holmium? → Holmium has the electron configuration [Xe] 4f¹¹ 6s². | What is holmium used for? → Holmium is used in Ho:YAG medical lasers, neutron absorbers, magnetic materials, spectroscopy standards and research compounds. ### Erbium (Er) — https://ferrumone.com/en/element/erbium Atom no: 68 | Lanthanide | Period 6, f-block **Title:** Erbium: Atomic Number, Uses and Isotopes **Description:** Erbium element guide: atomic number 68, symbol Er, atomic mass 167.26, electron configuration [Xe] 4f¹² 6s², EDFA fiber amplifiers, Er:YAG lasers and isotopes. **Keywords:** erbium element, erbium atomic number, erbium electron configuration, erbium uses, erbium isotopes, erbium doped fiber amplifier, EDFA, Er:YAG laser, erbium 1550 nm **Properties:** atomic mass 167.26 u; electron configuration [Xe] 4f¹² 6s²; state Solid; electronegativity 1.24 - **History:** Erbium was discovered by Carl Gustaf Mosander in 1843 from yttria minerals associated with Ytterby. Its name, like yttrium, terbium and ytterbium, traces back to the Swedish village Ytterby. - **Isotopes:** Erbium-162, About 0.14%, Rare stable isotope.; Erbium-164, About 1.6%, Stable isotope of erbium.; Erbium-166, About 33.5%, Most abundant natural erbium isotope.; Erbium-167, About 22.9%, NMR-active stable isotope.; Erbium-168, About 27.0%, Stable isotope of erbium.; Erbium-170, About 14.9%, Stable isotope of erbium. - **Compounds:** Er₂O₃ (Erbium(III) Oxide), Er:YAG (Erbium-Doped YAG), ErCl₃ (Erbium(III) Chloride), Er-doped fiber (Erbium-Doped Optical Fiber) - **Uses:** Erbium-doped fiber amplifiers, EDFAs, for 1550 nm optical communication networks; Er:YAG lasers near 2.94 micrometers for dental and dermatological procedures; Erbium oxide as a pink glass and ceramic colorant; Infrared-absorbing glass and optical filter materials; Erbium-ytterbium co-doped gain media for high-power fiber devices - **Biology:** Erbium has no known essential biological role and is considered a low-toxicity rare earth in normal material contexts. - **Interesting:** EDFA technology allowed long-distance fiber-optic signals to be amplified directly as light. Erbium’s 1550 nm emission matches a low-loss window of silica optical fiber. Er:YAG laser light is strongly absorbed by water, making it useful for precise tissue and dental applications. Ytterby is linked to the names of erbium, terbium, ytterbium and yttrium. - **Study notes:** Erbium has atomic number 68 and is a lanthanide. Its electron configuration is [Xe] 4f¹² 6s². The common oxidation state is +3. Remember erbium for EDFA telecom amplifiers and Er:YAG medical lasers. - **FAQ:** What is the atomic number of erbium? → The atomic number of erbium is 68. | What is the electron configuration of erbium? → Erbium has the electron configuration [Xe] 4f¹² 6s². | What is erbium used for? → Erbium is used in fiber amplifiers, Er:YAG lasers, pink glass colorants, infrared-absorbing glass and optical materials. ### Thulium (Tm) — https://ferrumone.com/en/element/thulium Atom no: 69 | Lanthanide | Period 6, f-block **Title:** Thulium: Atomic Number, Uses and Isotopes **Description:** Thulium element guide: atomic number 69, symbol Tm, atomic mass 168.93, electron configuration [Xe] 4f¹³ 6s², thulium-170, Tm:YAG lasers and uses. **Keywords:** thulium element, thulium atomic number, thulium electron configuration, thulium uses, thulium isotopes, thulium 170, Tm:YAG laser, thulium surgical laser, portable X-ray source **Properties:** atomic mass 168.93 u; electron configuration [Xe] 4f¹³ 6s²; state Solid; electronegativity 1.25 - **History:** Thulium was discovered in 1879 by Per Teodor Cleve. Its name comes from Thule, an ancient name used for the far northern lands of Scandinavia. - **Isotopes:** Thulium-169, 100%, The only stable natural thulium isotope.; Thulium-170, t½=About 129 days, Artificial isotope used as a portable X-ray source. - **Compounds:** Tm₂O₃ (Thulium(III) Oxide), Tm:YAG (Thulium-Doped YAG), TmCl₃ (Thulium(III) Chloride) - **Uses:** Thulium-170 as a compact radiation source for portable X-ray and industrial radiography devices; Tm:YAG lasers near 2 micrometers for surgical and medical laser systems; Thulium-doped fiber lasers and amplifiers in the 1.9-2.1 micrometer region; Thulium oxide and thulium compounds in blue-green phosphor and laser research - **Biology:** Thulium has no known essential biological role and is rarely encountered outside specialized materials and isotope applications. - **Interesting:** Thulium is often described as one of the least abundant lanthanides. Thulium-170 can provide X-ray radiation without a conventional electrically powered X-ray tube. Tm:YAG lasers operate near a water-absorbing infrared region useful for soft-tissue surgery. Natural thulium is monoisotopic, consisting of thulium-169. - **Study notes:** Thulium has atomic number 69 and is a lanthanide. Its electron configuration is [Xe] 4f¹³ 6s². The common oxidation state is +3. Remember thulium for Tm-170 portable X-ray sources and Tm:YAG surgical lasers. - **FAQ:** What is the atomic number of thulium? → The atomic number of thulium is 69. | What is the electron configuration of thulium? → Thulium has the electron configuration [Xe] 4f¹³ 6s². | What is thulium used for? → Thulium is used in Tm:YAG lasers, thulium-doped fiber lasers, portable X-ray source isotopes and specialized phosphor research. ### Ytterbium (Yb) — https://ferrumone.com/en/element/ytterbium Atom no: 70 | Lanthanide | Period 6, f-block **Title:** Ytterbium: Atomic Number, Uses and Isotopes **Description:** Ytterbium element guide: atomic number 70, symbol Yb, atomic mass 173.04, electron configuration [Xe] 4f¹⁴ 6s², fiber lasers, optical clocks and isotopes. **Keywords:** ytterbium element, ytterbium atomic number, ytterbium electron configuration, ytterbium uses, ytterbium isotopes, ytterbium fiber laser, Yb:YAG laser, ytterbium optical lattice clock, ytterbium 171 **Properties:** atomic mass 173.04 u; electron configuration [Xe] 4f¹⁴ 6s²; state Solid; electronegativity 1.1 - **History:** Ytterbium was discovered in 1878 by Jean Charles Galissard de Marignac from erbia fractions and named after Ytterby. Later work showed that the material also contained lutetium, clarifying ytterbium’s identity. - **Isotopes:** Ytterbium-168, About 0.12%, Rare stable isotope.; Ytterbium-170, About 3.0%, Stable isotope of ytterbium.; Ytterbium-171, About 14.1%, Important isotope for optical lattice clocks and precision measurement.; Ytterbium-172, About 21.7%, Stable isotope of ytterbium.; Ytterbium-173, About 16.1%, Stable isotope used in atomic physics research.; Ytterbium-174, About 32.0%, Most abundant natural ytterbium isotope.; Ytterbium-176, About 13.0%, Stable isotope of ytterbium. - **Compounds:** Yb₂O₃ (Ytterbium(III) Oxide), Yb:YAG (Ytterbium-Doped YAG), YbCl₃ (Ytterbium(III) Chloride), Yb(fod)₃ (Ytterbium Shift Reagent) - **Uses:** Ytterbium-doped fiber lasers for industrial cutting, welding and marking; Yb:YAG and ytterbium-doped laser crystals for efficient high-power solid-state lasers; Ytterbium optical lattice clocks for high-precision time and frequency metrology; Small alloy additions in stainless steel and specialty materials research; Ytterbium shift reagents and specialized spectroscopy chemistry - **Biology:** Ytterbium has no known essential biological role. Radioactive ytterbium isotopes have been studied or used in specialized radiation-source contexts. - **Interesting:** Ytterbium optical lattice clocks can reach fractional uncertainties near 10⁻¹⁸ in advanced metrology laboratories. Yb fiber lasers are efficient because ytterbium has a simple energy-level structure and can be pumped effectively. Ytterbium has a filled 4f¹⁴ shell, which helps make its chemistry relatively closed-shell among lanthanides. The Ytterby mineral site is linked to the names yttrium, terbium, erbium and ytterbium. - **Study notes:** Ytterbium has atomic number 70 and is a lanthanide. Its electron configuration is [Xe] 4f¹⁴ 6s². Ytterbium commonly shows +3 chemistry, while +2 chemistry is also notable. Remember Yb for fiber lasers, optical lattice clocks and a filled 4f shell. - **FAQ:** What is the atomic number of ytterbium? → The atomic number of ytterbium is 70. | What is the electron configuration of ytterbium? → Ytterbium has the electron configuration [Xe] 4f¹⁴ 6s². | What is ytterbium used for? → Ytterbium is used in fiber lasers, Yb:YAG lasers, optical lattice clocks, specialty alloys and spectroscopy chemistry. ### Lutetium (Lu) — https://ferrumone.com/en/element/lutetium Atom no: 71 | Lanthanide | Period 6, f-block **Title:** Lutetium: Atomic Number, Uses and Isotopes **Description:** Lutetium element guide: atomic number 71, symbol Lu, atomic mass 174.97, electron configuration [Xe] 4f¹⁴ 5d¹ 6s², Lu-177 therapy, LYSO PET and isotopes. **Keywords:** lutetium element, lutetium atomic number, lutetium electron configuration, lutetium uses, lutetium isotopes, lutetium 177, Lu-177 PSMA, LYSO PET detector, Lu-Hf dating **Properties:** atomic mass 174.97 u; electron configuration [Xe] 4f¹⁴ 5d¹ 6s²; state Solid; electronegativity 1.27 - **History:** Lutetium was separated from ytterbium-rich material in 1907 by Georges Urbain and independently by Carl Auer von Welsbach. Its name comes from Lutetia, the Latin name for Paris, after a long naming dispute with cassiopeium. - **Isotopes:** Lutetium-175, About 97.4%, Stable and dominant natural lutetium isotope.; Lutetium-176, About 2.6%, t½=About 3.73 x 10¹⁰ years, Long-lived beta-emitting isotope used in Lu-Hf geochronology.; Lutetium-177, t½=About 6.65 days, Medical beta-emitting radioisotope used in targeted radiotherapy. - **Compounds:** Lu₂O₃ (Lutetium(III) Oxide), Lu₂SiO₅:Ce (LSO Scintillator), Lu₁.₈Y₀.₂SiO₅:Ce (LYSO Scintillator), [¹⁷⁷Lu]Lu-PSMA-617 (Lutetium-177 PSMA) - **Uses:** Lutetium-177 PSMA and DOTATATE radiopharmaceuticals for targeted cancer therapy; LSO and LYSO scintillation crystals in PET medical imaging detectors; Lu-Hf isotope dating for meteorites, ancient rocks and mantle processes; Lutetium oxide catalysts and research materials; Dense rare earth compounds for detector and optical materials - **Biology:** Lutetium has no known essential biological role. Lutetium-177 labeled compounds are used in targeted nuclear medicine because they can deliver beta radiation to selected tumor cells. - **Interesting:** Lutetium is often treated as the final lanthanide because its 4f shell is filled and a 5d electron is present. The small ionic radius of Lu³⁺ is a visible result of lanthanide contraction. Lutetium-based PET crystals contain natural Lu-176, which produces intrinsic background radiation in detectors. Lu-Hf dating is valuable because Lu-176 decays to Hf-176 over geologic time. - **Study notes:** Lutetium has atomic number 71 and symbol Lu. Its electron configuration is [Xe] 4f¹⁴ 5d¹ 6s². The common oxidation state is +3. Remember lutetium for Lu-177 therapy, LYSO/LSO PET crystals and Lu-Hf dating. - **FAQ:** What is the atomic number of lutetium? → The atomic number of lutetium is 71. | What is the electron configuration of lutetium? → Lutetium has the electron configuration [Xe] 4f¹⁴ 5d¹ 6s². | What is lutetium used for? → Lutetium is used in Lu-177 radiotherapy, LSO and LYSO PET detector crystals, isotope dating and specialized catalysts. ### Hafnium (Hf) — https://ferrumone.com/en/element/hafnium Atom no: 72 | Transition Metal | Period 6, Group 4 **Title:** Hafnium: Atomic Number, Uses and Isotopes **Description:** Hafnium element guide: atomic number 72, symbol Hf, atomic mass 178.49, electron configuration [Xe] 4f¹⁴ 5d² 6s², HfO₂ high-k dielectric and isotopes. **Keywords:** hafnium element, hafnium atomic number, hafnium electron configuration, hafnium uses, hafnium isotopes, hafnium oxide, HfO2 high-k dielectric, hafnium control rods, hafnium zirconium similarity **Properties:** atomic mass 178.49 u; electron configuration [Xe] 4f¹⁴ 5d² 6s²; state Solid; electronegativity 1.3 - **History:** Hafnium was discovered in 1923 by Dirk Coster and George de Hevesy in Copenhagen using X-ray spectroscopy of zirconium minerals. Its name comes from Hafnia, the Latin name for Copenhagen. - **Isotopes:** Hafnium-174, About 0.16%, Rare natural hafnium isotope.; Hafnium-176, About 5.3%, Stable isotope and daughter product in Lu-Hf dating.; Hafnium-177, About 18.6%, Stable isotope of hafnium.; Hafnium-178, About 27.3%, Stable isotope; the Hf-178m2 isomer is a separate excited nuclear state.; Hafnium-179, About 13.6%, Stable isotope of hafnium.; Hafnium-180, About 35.1%, Most abundant natural hafnium isotope. - **Compounds:** HfO₂ (Hafnium Dioxide), HfCl₄ (Hafnium(IV) Chloride), HfC (Hafnium Carbide), HfN (Hafnium Nitride) - **Uses:** Hafnium oxide high-k gate dielectrics in modern microchips and transistors; Nuclear reactor control rods because hafnium absorbs neutrons strongly; Hafnium carbide and nitride ultra-high-temperature ceramics; Plasma cutting and welding electrodes; Specialty alloys and polymerization catalyst systems - **Biology:** Hafnium has no known essential biological role. It is mainly important as a nuclear and electronic material, with exposure concerns limited to industrial compounds and dusts. - **Interesting:** Hafnium and zirconium are extremely difficult to separate because lanthanide contraction makes their ionic radii very similar. HfO₂ helped semiconductor technology move beyond very thin SiO₂ gate layers by reducing leakage current. Hafnium absorbs neutrons strongly, while zirconium is valued in fuel cladding because it absorbs neutrons weakly. The element name honors Copenhagen, where the element was discovered. - **Study notes:** Hafnium has atomic number 72 and is a group 4 transition metal. Its electron configuration is [Xe] 4f¹⁴ 5d² 6s². The common oxidation state is +4. Remember HfO₂ for high-k dielectrics and hafnium metal for neutron control rods. - **FAQ:** What is the atomic number of hafnium? → The atomic number of hafnium is 72. | What is the electron configuration of hafnium? → Hafnium has the electron configuration [Xe] 4f¹⁴ 5d² 6s². | What is hafnium used for? → Hafnium is used in high-k dielectrics, reactor control rods, refractory ceramics, plasma electrodes and specialty catalysts. ### Tantalum (Ta) — https://ferrumone.com/en/element/tantalum Atom no: 73 | Transition Metal | Period 6, Group 5 **Title:** Tantalum: Atomic Number, Uses and Isotopes **Description:** Tantalum element guide: atomic number 73, symbol Ta, atomic mass 180.95, electron configuration [Xe] 4f¹⁴ 5d³ 6s², capacitors, implants and isotopes. **Keywords:** tantalum element, tantalum atomic number, tantalum electron configuration, tantalum uses, tantalum isotopes, tantalum capacitors, Ta2O5 dielectric, tantalum implants, tantalum 180m **Properties:** atomic mass 180.95 u; electron configuration [Xe] 4f¹⁴ 5d³ 6s²; state Solid; electronegativity 1.5 - **History:** Tantalum was discovered in 1802 by Anders Gustaf Ekeberg. It was named after Tantalus from Greek mythology because its minerals resisted dissolution, echoing the myth of unreachable water. - **Isotopes:** Tantalum-180m, About 0.012%, t½=Longer than 10¹⁶ years, Extremely rare naturally occurring nuclear isomer, effectively stable on human timescales.; Tantalum-181, About 99.988%, Dominant stable natural tantalum isotope. - **Compounds:** Ta₂O₅ (Tantalum(V) Oxide), TaC (Tantalum Carbide), TaCl₅ (Tantalum(V) Chloride), LiTaO₃ (Lithium Tantalate) - **Uses:** Tantalum capacitors for compact electronics with high capacitance density; Ta₂O₅ dielectric films in capacitors and optical coatings; Biocompatible implants, porous bone materials and surgical components; High-temperature superalloys for turbine and aerospace parts; Corrosion-resistant chemical equipment for aggressive acids - **Biology:** Tantalum has no essential biological role, but metallic tantalum is highly biocompatible and corrosion resistant, making it useful in medical implants. - **Interesting:** Tantalum forms a protective oxide film that explains both its corrosion resistance and its capacitor value. Coltan ores contain tantalum and niobium minerals, which is why tantalum supply chains are often discussed in conflict-mineral contexts. Tantalum-180m is one of the strangest naturally occurring nuclides because it is a very long-lived excited nuclear state. Tantalum is resistant to many acids, but hydrofluoric acid can attack it. - **Study notes:** Tantalum has atomic number 73 and is a group 5 transition metal. Its electron configuration is [Xe] 4f¹⁴ 5d³ 6s². The common oxidation state is +5. Remember Ta₂O₅ for capacitors and tantalum metal for corrosion-resistant, biocompatible implants. - **FAQ:** What is the atomic number of tantalum? → The atomic number of tantalum is 73. | What is the electron configuration of tantalum? → Tantalum has the electron configuration [Xe] 4f¹⁴ 5d³ 6s². | What is tantalum used for? → Tantalum is used in capacitors, medical implants, corrosion-resistant equipment, superalloys and hard carbide materials. ### Tungsten (W) — https://ferrumone.com/en/element/tungsten Atom no: 74 | Transition Metal | Period 6, Group 6 **Title:** Tungsten: Atomic Number, Uses and Isotopes **Description:** Tungsten element guide: atomic number 74, symbol W, atomic mass 183.84, electron configuration [Xe] 4f¹⁴ 5d⁴ 6s², highest melting point and tungsten carbide. **Keywords:** tungsten element, tungsten atomic number, tungsten electron configuration, tungsten uses, tungsten isotopes, tungsten carbide, tungsten melting point, why is tungsten symbol W, wolfram tungsten **Properties:** atomic mass 183.84 u; electron configuration [Xe] 4f¹⁴ 5d⁴ 6s²; state Solid; electronegativity 2.36 - **History:** Tungsten was isolated in 1783 by the Elhuyar brothers after earlier work by Carl Wilhelm Scheele on tungstic acid. The English name comes from Swedish words meaning heavy stone, while the symbol W comes from wolfram. - **Isotopes:** Tungsten-180, About 0.12%, Rare natural tungsten isotope.; Tungsten-182, About 26.5%, Stable isotope of tungsten.; Tungsten-183, About 14.3%, NMR-active stable isotope.; Tungsten-184, About 30.6%, Most abundant natural tungsten isotope.; Tungsten-186, About 28.4%, Stable isotope, although extremely rare double-beta decay is theoretically possible. - **Compounds:** WC (Tungsten Carbide), WO₃ (Tungsten(VI) Oxide), Na₂WO₄ (Sodium Tungstate), WS₂ (Tungsten Disulfide) - **Uses:** Tungsten carbide cutting tools, drills, dies and wear-resistant parts; High-speed steels and refractory alloys for high-temperature service; X-ray tube anodes and radiation shielding because of high atomic number and density; TIG welding electrodes and electrical contacts; Historical incandescent lamp filaments due to extreme melting point - **Biology:** Tungsten is not essential for humans. Some anaerobic microorganisms use tungsten-containing enzymes, where tungsten can play roles similar to molybdenum in redox chemistry. - **Interesting:** Tungsten has the highest melting point of all elements, about 3422 °C. The symbol W preserves the older name wolfram, still used in several languages. Tungsten carbide is much harder than steel and is central to modern machining. Tungsten is dense enough to be considered in some applications as a non-lead radiation shielding material. - **Study notes:** Tungsten has atomic number 74 and symbol W. Its electron configuration is [Xe] 4f¹⁴ 5d⁴ 6s². The common high oxidation state is +6. Remember tungsten for the highest melting point and WC for cutting tools. - **FAQ:** What is the atomic number of tungsten? → The atomic number of tungsten is 74. | What is the electron configuration of tungsten? → Tungsten has the electron configuration [Xe] 4f¹⁴ 5d⁴ 6s². | What is tungsten used for? → Tungsten is used in tungsten carbide tools, high-temperature alloys, X-ray tubes, welding electrodes, radiation shielding and historical lamp filaments. ### Rhenium (Re) — https://ferrumone.com/en/element/rhenium Atom no: 75 | Transition Metal | Period 6, Group 7 **Title:** Rhenium: Atomic Number, Uses and Isotopes **Description:** Rhenium element guide: atomic number 75, symbol Re, atomic mass 186.21, electron configuration [Xe] 4f¹⁴ 5d⁵ 6s², superalloys, catalysts and isotopes. **Keywords:** rhenium element, rhenium atomic number, rhenium electron configuration, rhenium uses, rhenium isotopes, rhenium superalloys, platinum rhenium catalyst, Re-Os dating, rhenium 187 **Properties:** atomic mass 186.21 u; electron configuration [Xe] 4f¹⁴ 5d⁵ 6s²; state Solid; electronegativity 1.9 - **History:** Rhenium was discovered in 1925 by Walter Noddack, Ida Tacke and Otto Berg. Its name comes from Rhenus, the Latin name for the Rhine River, and it was one of the last naturally occurring stable elements to be discovered. - **Isotopes:** Rhenium-185, About 37.4%, Stable natural rhenium isotope.; Rhenium-187, About 62.6%, t½=About 4.16 x 10¹⁰ years, Long-lived beta emitter that decays to osmium-187 and is used in Re-Os dating. - **Compounds:** Re₂O₇ (Rhenium(VII) Oxide), ReO₄⁻ (Perrhenate Ion), ReS₂ (Rhenium Disulfide), W-Re (Tungsten-Rhenium Alloy) - **Uses:** Nickel-based superalloys for single-crystal jet-engine turbine blades; Platinum-rhenium catalysts for petroleum reforming and high-octane fuels; Tungsten-rhenium thermocouples for very high-temperature measurement; Re-Os isotope dating of sulfide ores, meteorites and mantle rocks; Rhenium radioisotopes in targeted radiotherapy research - **Biology:** Rhenium has no known essential biological role. Radioactive rhenium isotopes such as rhenium-186 and rhenium-188 are studied for radiotherapy and nuclear medicine applications. - **Interesting:** Rhenium is among the rarest stable metals in Earth’s crust. Small rhenium additions can greatly improve creep resistance in nickel turbine superalloys. Re-187 decays to Os-187, creating a useful isotope clock for geology. Rhenium was discovered after many common elements because it is rare and widely dispersed rather than concentrated in obvious ores. - **Study notes:** Rhenium has atomic number 75 and is a group 7 transition metal. Its electron configuration is [Xe] 4f¹⁴ 5d⁵ 6s². Rhenium can reach high oxidation states, especially +7. Remember Re for superalloys, Pt-Re catalysts and Re-Os dating. - **FAQ:** What is the atomic number of rhenium? → The atomic number of rhenium is 75. | What is the electron configuration of rhenium? → Rhenium has the electron configuration [Xe] 4f¹⁴ 5d⁵ 6s². | What is rhenium used for? → Rhenium is used in jet-engine superalloys, platinum-rhenium catalysts, high-temperature thermocouples, isotope dating and radiotherapy research. ### Osmium (Os) — https://ferrumone.com/en/element/osmium Atom no: 76 | Transition Metal | Period 6, Group 8 **Title:** Osmium: Atomic Number, Uses and Isotopes **Description:** Osmium element guide: atomic number 76, symbol Os, atomic mass 190.23, electron configuration [Xe] 4f¹⁴ 5d⁶ 6s², density, osmium tetroxide and isotopes. **Keywords:** osmium element, osmium atomic number, osmium electron configuration, osmium uses, osmium isotopes, osmium density, osmium tetroxide, OsO4, Re-Os dating **Properties:** atomic mass 190.23 u; electron configuration [Xe] 4f¹⁴ 5d⁶ 6s²; state Solid; electronegativity 2.2 - **History:** Osmium was discovered in 1803 by Smithson Tennant in the residue left after crude platinum was dissolved in aqua regia. Its name comes from the Greek word osme, meaning smell, because osmium tetroxide has a sharp odor. - **Isotopes:** Osmium-184, About 0.02%, t½=About 1.1 x 10¹³ years, Extremely long-lived alpha-emitting natural osmium isotope.; Osmium-186, About 1.6%, t½=About 2 x 10¹⁵ years, Extremely long-lived alpha-emitting isotope, linked to rhenium-osmium isotope studies.; Osmium-187, About 2.0%, Daughter isotope from rhenium-187 decay in Re-Os dating.; Osmium-188, About 13.2%, Stable isotope of osmium.; Osmium-189, About 16.1%, Stable isotope of osmium.; Osmium-190, About 26.3%, Stable isotope of osmium.; Osmium-192, About 40.8%, Most abundant natural osmium isotope. - **Compounds:** OsO₄ (Osmium Tetroxide), OsCl₃ (Osmium(III) Chloride), [Os(bpy)₃]²⁺ (Tris(bipyridyl)osmium(II)) - **Uses:** Osmium tetroxide staining of lipids and membranes for electron microscopy; Osmium tetroxide in alkene dihydroxylation chemistry, including Sharpless methods; Hard osmium-iridium alloys for wear-resistant tips and contacts; Re-Os isotope dating and platinum-group element geochemistry; Specialized organometallic and photoredox research compounds - **Biology:** Osmium has no known essential biological role. Osmium tetroxide is highly toxic and volatile, so it must be handled with strict laboratory controls. - **Interesting:** Osmium is usually cited as the densest naturally occurring element, very close to iridium. Osmium tetroxide is useful because it reacts strongly with carbon-carbon double bonds, especially in lipids. The name osmium comes from smell, reflecting the odor of volatile OsO₄. Osmium-187 helps connect rhenium decay to geologic dating systems. - **Study notes:** Osmium has atomic number 76 and is a platinum-group metal. Its electron configuration is [Xe] 4f¹⁴ 5d⁶ 6s². Osmium can show high oxidation states, including +8 in OsO₄. Remember osmium for very high density and toxic osmium tetroxide. - **FAQ:** What is the atomic number of osmium? → The atomic number of osmium is 76. | What is the electron configuration of osmium? → Osmium has the electron configuration [Xe] 4f¹⁴ 5d⁶ 6s². | What is osmium used for? → Osmium is used mainly in specialized forms such as osmium tetroxide for microscopy and synthesis, hard alloys and isotope studies. ### Iridium (Ir) — https://ferrumone.com/en/element/iridium Atom no: 77 | Transition Metal | Period 6, Group 9 **Title:** Iridium: Atomic Number, Uses and Isotopes **Description:** Iridium element guide: atomic number 77, symbol Ir, atomic mass 192.22, electron configuration [Xe] 4f¹⁴ 5d⁷ 6s², K-Pg anomaly, spark plugs and isotopes. **Keywords:** iridium element, iridium atomic number, iridium electron configuration, iridium uses, iridium isotopes, iridium anomaly, K-Pg boundary iridium, iridium spark plugs, iridium 192 **Properties:** atomic mass 192.22 u; electron configuration [Xe] 4f¹⁴ 5d⁷ 6s²; state Solid; electronegativity 2.2 - **History:** Iridium was discovered in 1803 by Smithson Tennant in platinum ore residues. Its name comes from Iris, the rainbow, because many iridium salts show vivid colors. - **Isotopes:** Iridium-191, About 37.3%, Stable natural iridium isotope.; Iridium-192, t½=About 73.8 days, Artificial gamma-emitting isotope used in brachytherapy and industrial radiography.; Iridium-193, About 62.7%, Most abundant stable natural iridium isotope. - **Compounds:** IrO₂ (Iridium(IV) Oxide), Ir(ppy)₃ (Tris(phenylpyridine)iridium), IrCl₃ (Iridium(III) Chloride) - **Uses:** Iridium or platinum-iridium spark plug electrodes for long service life; Iridium-192 sources for brachytherapy and industrial radiography; Iridium oxide catalysts for oxygen evolution in acidic electrolysis; Phosphorescent iridium complexes in OLED display materials; Corrosion-resistant crucibles, electrodes and high-temperature alloys - **Biology:** Iridium has no known essential biological role. Iridium-192 is used as a sealed radiation source in brachytherapy and industrial radiography under controlled conditions. - **Interesting:** A global iridium-rich layer at the K-Pg boundary helped support the asteroid-impact explanation for the dinosaur extinction event. Iridium is among the most corrosion-resistant metals known. Iridium complexes can harvest triplet excitons, which makes them important in phosphorescent OLED technology. Iridium spark plug tips can be very small because iridium resists melting and erosion. - **Study notes:** Iridium has atomic number 77 and is a platinum-group metal. Its electron configuration is [Xe] 4f¹⁴ 5d⁷ 6s². Common oxidation states include +3 and +4. Remember iridium for the K-Pg boundary anomaly, spark plugs, Ir-192 and OLED emitters. - **FAQ:** What is the atomic number of iridium? → The atomic number of iridium is 77. | What is the electron configuration of iridium? → Iridium has the electron configuration [Xe] 4f¹⁴ 5d⁷ 6s². | What is iridium used for? → Iridium is used in spark plugs, Ir-192 radiation sources, OLED emitters, oxygen-evolution catalysts and corrosion-resistant equipment. ### Platinum (Pt) — https://ferrumone.com/en/element/platinum Atom no: 78 | Transition Metal | Period 6, Group 10 **Title:** Platinum: Atomic Number, Uses and Isotopes **Description:** Platinum element guide: atomic number 78, symbol Pt, atomic mass 195.08, electron configuration [Xe] 4f¹⁴ 5d⁹ 6s¹, catalytic converters, cisplatin and isotopes. **Keywords:** platinum element, platinum atomic number, platinum electron configuration, platinum uses, platinum isotopes, platinum catalytic converter, cisplatin, platinum fuel cell catalyst, platinum group metal **Properties:** atomic mass 195.08 u; electron configuration [Xe] 4f¹⁴ 5d⁹ 6s¹; state Solid; electronegativity 2.28 - **History:** Platinum was used by pre-Columbian peoples in South America and became known to Europeans from platinum-bearing gold ores. The name comes from Spanish platina, meaning little silver. - **Isotopes:** Platinum-190, About 0.01%, t½=About 4.8 x 10¹¹ years, Very rare long-lived alpha-emitting natural platinum isotope.; Platinum-192, About 0.78%, Stable isotope of platinum.; Platinum-194, About 32.9%, Stable isotope of platinum.; Platinum-195, About 33.8%, Most abundant natural platinum isotope and NMR-active isotope.; Platinum-196, About 25.2%, Stable isotope of platinum.; Platinum-198, About 7.4%, Stable isotope of platinum. - **Compounds:** cis-[Pt(NH₃)₂Cl₂] (Cisplatin), H₂PtCl₆ (Chloroplatinic Acid), PtO₂ (Adams Catalyst), Pt/C (Platinum on Carbon) - **Uses:** Automotive catalytic converters for converting CO, hydrocarbons and nitrogen oxides; PEM fuel cell catalysts for hydrogen oxidation and oxygen reduction; Cisplatin and related platinum chemotherapy drugs; Jewelry, investment metals and corrosion-resistant laboratory ware; Petroleum reforming and hydrogenation catalysts - **Biology:** Elemental platinum has no essential biological role and is relatively inert. Platinum compounds such as cisplatin and carboplatin are important chemotherapy drugs that act by damaging DNA in cancer cells. - **Interesting:** Platinum catalytic converters are a major reason modern car exhaust is cleaner than untreated exhaust. Cisplatin helped transform treatment outcomes for some cancers, especially testicular cancer. The old international kilogram prototype was a platinum-iridium alloy cylinder. Platinum is less reactive than many metals, which helps explain its corrosion resistance and use in jewelry. - **Study notes:** Platinum has atomic number 78 and symbol Pt. Its electron configuration is [Xe] 4f¹⁴ 5d⁹ 6s¹. Common oxidation states include +2 and +4. Remember platinum for catalytic converters, fuel cells and cisplatin chemotherapy. - **FAQ:** What is the atomic number of platinum? → The atomic number of platinum is 78. | What is the electron configuration of platinum? → Platinum has the electron configuration [Xe] 4f¹⁴ 5d⁹ 6s¹. | What is platinum used for? → Platinum is used in catalytic converters, fuel cells, chemotherapy drugs, jewelry, petroleum catalysts and laboratory equipment. ### Gold (Au) — https://ferrumone.com/en/element/gold Atom no: 79 | Transition Metal | Period 6, Group 11 **Title:** Gold: Atomic Number, Uses and Isotopes **Description:** Gold element guide: atomic number 79, symbol Au, atomic mass 196.97, electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s¹, uses, nanoparticles and isotopes. **Keywords:** gold element, gold atomic number, gold electron configuration, gold uses, gold isotopes, gold symbol Au, gold nanoparticles, why is gold yellow, James Webb gold coating **Properties:** atomic mass 196.97 u; electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s¹; state Solid; electronegativity 2.54 - **History:** Gold has been known since ancient times and was one of the first metals worked by humans. Its symbol Au comes from Latin aurum, and gold has shaped coinage, trade, jewelry and monetary systems for thousands of years. - **Isotopes:** Gold-197, 100%, The only stable natural gold isotope.; Gold-198, t½=About 2.7 days, Artificial beta- and gamma-emitting isotope used in research and some medical contexts. - **Compounds:** AuCl₃ (Gold(III) Chloride), HAuCl₄ (Chloroauric Acid), Auranofin (Auranofin), AuNP (Gold Nanoparticles) - **Uses:** Jewelry, coins, investment bars and cultural objects; Corrosion-resistant electrical contacts, bond wires and connectors; Gold nanoparticles in lateral-flow diagnostic tests and biomedical research; Infrared-reflective coatings, including gold-coated space telescope mirrors; Dental alloys and specialized catalysis or nanotechnology applications - **Biology:** Elemental gold has no essential biological role and is generally inert. Gold nanoparticles and gold compounds are used in diagnostic tests, research and some medical contexts such as auranofin. - **Interesting:** Gold’s yellow color is explained by relativistic effects that shift electronic transitions into the visible region. Gold nanoparticles can appear red or purple because of localized surface plasmon resonance. The James Webb Space Telescope uses a thin gold coating because gold reflects infrared light very well. Gold is highly malleable; very small amounts can be beaten into extremely thin leaf. - **Study notes:** Gold has atomic number 79 and symbol Au. Its electron configuration is [Xe] 4f¹⁴ 5d¹⁰ 6s¹. Common oxidation states include +1 and +3. Remember gold for noble-metal behavior, electronics contacts, nanoparticles and relativistic color. - **FAQ:** What is the atomic number of gold? → The atomic number of gold is 79. | What is the electron configuration of gold? → Gold has the electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s¹. | What is gold used for? → Gold is used in jewelry, electronics, coins, diagnostics, nanoparticles, coatings and dental or specialty materials. ### Mercury (Hg) — https://ferrumone.com/en/element/mercury Atom no: 80 | Transition Metal | Period 6, Group 12 **Title:** Mercury: Atomic Number, Uses and Isotopes **Description:** Mercury element guide: atomic number 80, symbol Hg, atomic mass 200.59, electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s², liquid metal, toxicity and isotopes. **Keywords:** mercury element, mercury atomic number, mercury electron configuration, mercury uses, mercury isotopes, liquid metal mercury, mercury toxicity, methylmercury, Minamata disease **Properties:** atomic mass 200.59 u; electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s²; state Liquid; electronegativity 2 - **History:** Mercury has been known since ancient times. Its symbol Hg comes from Latin hydrargyrum, meaning liquid silver. It was used in barometers and thermometers, and industrial mercury pollution later became infamous through Minamata disease in Japan. - **Isotopes:** Mercury-196, About 0.15%, Rare stable isotope of mercury.; Mercury-198, About 10.0%, Stable isotope of mercury.; Mercury-199, About 16.9%, NMR-active stable isotope.; Mercury-200, About 23.1%, Stable isotope of mercury.; Mercury-201, About 13.2%, NMR-active stable isotope.; Mercury-202, About 29.9%, Most abundant natural mercury isotope.; Mercury-204, About 6.9%, Stable isotope of mercury. - **Compounds:** HgCl₂ (Mercury(II) Chloride), Hg₂Cl₂ (Calomel), CH₃Hg⁺ (Methylmercury), HgS (Mercury(II) Sulfide) - **Uses:** Historical thermometers, barometers and manometers, now widely replaced because of toxicity; Fluorescent and mercury-vapor lamps, where mercury vapor emits ultraviolet light; Dental amalgam fillings, now restricted or reduced in many regions; Artisanal gold extraction by mercury amalgamation, a major pollution source; Chemical and electrochemical applications that have declined under mercury-control regulations - **Biology:** Mercury has no essential biological role and is toxic in elemental, inorganic and organic forms. Methylmercury is especially dangerous because it accumulates in aquatic food chains and can damage the nervous system. - **Interesting:** Mercury is the only metal that is liquid at ordinary room temperature. Relativistic effects help explain mercury’s weak metal-metal bonding and unusually low melting point. Methylmercury biomagnifies, so large predatory fish can contain higher mercury levels than surrounding water. The Minamata Convention is an international treaty aimed at reducing mercury pollution and exposure. - **Study notes:** Mercury has atomic number 80 and symbol Hg. Its electron configuration is [Xe] 4f¹⁴ 5d¹⁰ 6s². Common oxidation states are +1 and +2. Remember mercury for liquid metal behavior, toxicity and methylmercury biomagnification. - **FAQ:** What is the atomic number of mercury? → The atomic number of mercury is 80. | What is the electron configuration of mercury? → Mercury has the electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s². | What is mercury used for? → Mercury has been used in thermometers, barometers, fluorescent lamps, dental amalgams and gold extraction, though many uses are now restricted because of toxicity. ### Thallium (Tl) — https://ferrumone.com/en/element/thallium Atom no: 81 | Post-Transition Metal | Period 6, Group 13 **Title:** Thallium: Atomic Number, Uses and Isotopes **Description:** Thallium element guide: atomic number 81, symbol Tl, atomic mass 204.38, electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹, toxicity, Tl-201 and isotopes. **Keywords:** thallium element, thallium atomic number, thallium electron configuration, thallium uses, thallium isotopes, thallium toxicity, thallium 201 SPECT, NaI(Tl) scintillator, thallium poisoning **Properties:** atomic mass 204.38 u; electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹; state Solid; electronegativity 1.62 - **History:** Thallium was discovered in 1861 by William Crookes from a bright green spectral line in residues from sulfuric acid production. Its name comes from the Greek thallos, meaning green shoot, and Claude-Auguste Lamy soon isolated the metal. - **Isotopes:** Thallium-201, t½=About 73 hours, Artificial radioisotope used in myocardial perfusion SPECT imaging.; Thallium-203, About 29.5%, Stable natural thallium isotope.; Thallium-205, About 70.5%, Dominant stable natural thallium isotope. - **Compounds:** TlBr (Thallium(I) Bromide), NaI(Tl) (Thallium-Doped Sodium Iodide), Tl₂SO₄ (Thallium(I) Sulfate), TlCl (Thallium(I) Chloride) - **Uses:** Thallium-201 chloride for myocardial perfusion SPECT and cardiac viability imaging; Thallium bromide and iodide crystals for room-temperature radiation detectors; NaI(Tl) scintillation crystals for gamma-ray detection; Low-temperature mercury-thallium alloys in historical thermometer applications; Thallium sulfate as a historical rodenticide, now banned or restricted in many places - **Biology:** Thallium has no essential biological role and is highly toxic. Tl⁺ can mimic potassium ions in some biological transport systems, which helps explain its neurological and systemic toxicity. - **Interesting:** Thallium poisoning can be difficult to recognize because it may be colorless, tasteless and delayed in symptoms. Prussian blue is used as an antidote because it can bind thallium ions in the gut and reduce reabsorption. Thallium often prefers the +1 oxidation state because of the inert pair effect on the 6s² electrons. Thallium-201 behaves partly like potassium in heart tissue, which is why it can map myocardial perfusion. - **Study notes:** Thallium has atomic number 81 and symbol Tl. Its electron configuration is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹. The +1 oxidation state is especially important because of the inert pair effect. Remember thallium for toxicity, Tl-201 SPECT and NaI(Tl) scintillators. - **FAQ:** What is the atomic number of thallium? → The atomic number of thallium is 81. | What is the electron configuration of thallium? → Thallium has the electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹. | What is thallium used for? → Thallium is used in Tl-201 medical imaging, radiation detector crystals, NaI(Tl) scintillators and some specialized materials. ### Lead (Pb) — https://ferrumone.com/en/element/lead Atom no: 82 | Post-Transition Metal | Period 6, Group 14 **Title:** Lead: Atomic Number, Uses and Isotopes **Description:** Lead element guide: atomic number 82, symbol Pb, atomic mass 207.2, electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p², toxicity, batteries and isotopes. **Keywords:** lead element, lead atomic number, lead electron configuration, lead uses, lead isotopes, lead toxicity, lead acid battery, lead radiation shielding, U-Pb dating **Properties:** atomic mass 207.2 u; electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p²; state Solid; electronegativity 2.33 - **History:** Lead has been used since ancient times. Its symbol Pb comes from Latin plumbum, the root of plumbing, because lead was historically used in pipes, vessels, pigments and alloys. - **Isotopes:** Lead-204, About 1.4%, Primordial stable lead isotope, not a major radiogenic decay product.; Lead-206, About 24.1%, Stable end product of the uranium-238 decay chain.; Lead-207, About 22.1%, Stable end product of the uranium-235 decay chain.; Lead-208, About 52.4%, Most abundant lead isotope and stable end product of the thorium-232 decay chain. - **Compounds:** PbSO₄ (Lead(II) Sulfate), PbO₂ (Lead(IV) Oxide), Pb(C₂H₅)₄ (Tetraethyllead), PbS (Lead(II) Sulfide) - **Uses:** Lead-acid batteries for vehicles, backup power and industrial storage; Radiation shielding for X-rays and gamma rays; U-Pb and Th-Pb geochronology using radiogenic lead isotopes; Historical solders, paints and pipes, many now restricted because of toxicity; Weights, ballast and specialized alloys where density is useful - **Biology:** Lead has no essential biological role and is a serious neurotoxin. Pb²⁺ can interfere with heme synthesis and nervous system development, which makes lead exposure especially dangerous for children. - **Interesting:** The word plumbing comes from plumbum, the Latin name behind the symbol Pb. Lead-208 has magic numbers of protons and neutrons, making it unusually stable among heavy nuclei. Lead isotope ratios are powerful tools for dating rocks and tracing pollution sources. Lead-acid batteries are among the most recycled consumer products in many countries. - **Study notes:** Lead has atomic number 82 and symbol Pb. Its electron configuration is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p². The +2 oxidation state is especially important because of the inert pair effect. Remember lead for toxicity, batteries, shielding and U-Pb dating. - **FAQ:** What is the atomic number of lead? → The atomic number of lead is 82. | What is the electron configuration of lead? → Lead has the electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p². | What is lead used for? → Lead is used in lead-acid batteries, radiation shielding, weights, specialized alloys and isotope dating, while many older uses were restricted because of toxicity. ### Bismuth (Bi) — https://ferrumone.com/en/element/bismuth Atom no: 83 | Post-Transition Metal | Period 6, Group 15 **Title:** Bismuth: Atomic Number, Uses and Isotopes **Description:** Bismuth element guide: atomic number 83, symbol Bi, atomic mass 208.98, electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p³, Bi-209 and uses. **Keywords:** bismuth element, bismuth atomic number, bismuth electron configuration, bismuth uses, bismuth isotopes, bismuth subsalicylate, bismuth telluride, bismuth 209 half life, bismuth crystals **Properties:** atomic mass 208.98 u; electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p³; state Solid; electronegativity 2.02 - **History:** Bismuth was known to miners and metalworkers for centuries, but it was clearly distinguished from lead and tin in the 18th century. Its name likely comes from the German Wismut. - **Isotopes:** Bismuth-209, 100%, t½=About 1.9 x 10¹⁹ years, Extremely long-lived alpha emitter, effectively stable for practical chemistry.; Bismuth-213, t½=About 45.6 minutes, Artificial isotope studied for targeted alpha therapy. - **Compounds:** BiC₇H₅O₄·H₂O (Bismuth Subsalicylate), Bi₂Te₃ (Bismuth Telluride), BiVO₄ (Bismuth Vanadate), Bi₂O₃ (Bismuth(III) Oxide) - **Uses:** Bismuth subsalicylate in over-the-counter digestive medicines; Bismuth telluride thermoelectric coolers and generators; Low-melting alloys for fuses, fire sprinklers and special casting materials; Bismuth vanadate yellow pigment as a safer alternative to some heavy-metal pigments; Bismuth radioisotopes in targeted alpha therapy research - **Biology:** Bismuth has no essential biological role, but many bismuth compounds have relatively low toxicity compared with other heavy metals. Bismuth subsalicylate is used in digestive medicines. - **Interesting:** Bismuth-209 was long considered stable until its extremely slow alpha decay was measured. Bismuth expands slightly as it solidifies, a rare behavior among metals. Bismuth crystals can show rainbow colors because thin oxide layers create optical interference. Bismuth compounds often replace more toxic lead compounds in some applications. - **Study notes:** Bismuth has atomic number 83 and symbol Bi. Its electron configuration is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p³. The +3 oxidation state is most common; +5 is less stable because of the inert pair effect. Remember bismuth for subsalicylate medicine, Bi₂Te₃ thermoelectrics and long-lived Bi-209. - **FAQ:** What is the atomic number of bismuth? → The atomic number of bismuth is 83. | What is the electron configuration of bismuth? → Bismuth has the electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p³. | What is bismuth used for? → Bismuth is used in digestive medicines, thermoelectric materials, low-melting alloys, pigments and research radioisotopes. ### Polonium (Po) — https://ferrumone.com/en/element/polonium Atom no: 84 | Post-Transition Metal | Period 6, Group 16 **Title:** Polonium: Atomic Number, Uses and Isotopes **Description:** Polonium element guide: atomic number 84, symbol Po, atomic mass 209, electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁴, Po-210 and isotopes. **Keywords:** polonium element, polonium atomic number, polonium electron configuration, polonium uses, polonium isotopes, polonium 210, Po-210 alpha emitter, polonium static eliminator, Litvinenko polonium **Properties:** atomic mass 209 u; electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁴; state Solid; electronegativity 2 - **History:** Polonium was discovered in 1898 by Marie Curie and Pierre Curie while studying pitchblende. Marie Curie named it after Poland, her homeland, at a time when Poland was partitioned. - **Isotopes:** Polonium-209, t½=About 125 years, Longest-lived polonium isotope, used in research and tracer contexts.; Polonium-210, t½=About 138 days, Alpha-emitting isotope found in uranium decay chains and used in static eliminators. - **Compounds:** PoO₂ (Polonium(IV) Oxide), PoCl₄ (Polonium(IV) Chloride) - **Uses:** Polonium-210 static eliminators that ionize air to remove static charge; Polonium-210 heat sources in some historical space and remote systems; Alpha-particle sources for nuclear physics research; Polonium-beryllium neutron source history - **Biology:** Polonium has no biological role. Polonium-210 is an intense alpha emitter and is extremely dangerous if inhaled or ingested, even though alpha particles have low external penetration. - **Interesting:** Polonium was the first element discovered by Marie Curie. Po-210 has very high specific activity and can generate heat from radioactive decay. Polonium-beryllium sources helped early neutron research by producing neutrons from alpha bombardment of beryllium. The 2006 Alexander Litvinenko poisoning made Po-210 widely known outside nuclear science. - **Study notes:** Polonium has atomic number 84 and symbol Po. Its electron configuration is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁴. All polonium isotopes are radioactive. Remember Po-210 for alpha emission, static eliminators and severe internal toxicity. - **FAQ:** What is the atomic number of polonium? → The atomic number of polonium is 84. | What is the electron configuration of polonium? → Polonium has the electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁴. | What is polonium used for? → Polonium is used mainly in specialized static eliminators, alpha-source research and historical heat-source or neutron-source applications. ### Astatine (At) — https://ferrumone.com/en/element/astatine Atom no: 85 | Halogen | Period 6, Group 17 **Title:** Astatine: Atomic Number, Uses and Isotopes **Description:** Astatine element guide: atomic number 85, symbol At, atomic mass 210, electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵, At-211 and isotopes. **Keywords:** astatine element, astatine atomic number, astatine electron configuration, astatine uses, astatine isotopes, astatine 211, At-211 targeted alpha therapy, rarest natural element, radioactive halogen **Properties:** atomic mass 210 u; electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵; state Solid; electronegativity 2.2 - **History:** Astatine was synthesized in 1940 by Dale Corson, Kenneth MacKenzie and Emilio Segrè at Berkeley by bombarding bismuth with alpha particles. Its name comes from Greek astatos, meaning unstable. - **Isotopes:** Astatine-210, t½=About 8.1 hours, One of the longer-lived astatine isotopes.; Astatine-211, t½=About 7.2 hours, Alpha-emitting isotope studied for targeted alpha therapy. - **Compounds:** AtI (Astatine Iodide), C₆H₅At (Astatobenzene) - **Uses:** Astatine-211 targeted alpha therapy research for cancer treatment; Heavy-halogen chemistry studies of astatide and organoastatine compounds; Radiolabeling research for antibodies, peptides and small molecules; Fundamental studies of relativistic effects in heavy halogens - **Biology:** Astatine has no natural biological role because all of its isotopes are radioactive and short-lived. Astatine-211 radiopharmaceuticals are being studied for targeted alpha therapy. - **Interesting:** Astatine is often described as the rarest naturally occurring element on Earth. All astatine isotopes are radioactive, so macroscopic chemistry is extremely difficult. Astatine is the heaviest halogen and can show both halogen-like and more metallic behavior. At-211 is attractive in nuclear medicine research because alpha particles travel only a short distance in tissue. - **Study notes:** Astatine has atomic number 85 and symbol At. Its electron configuration is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵. Astatine is a radioactive halogen. Remember At-211 for targeted alpha therapy research and astatine for extreme natural rarity. - **FAQ:** What is the atomic number of astatine? → The atomic number of astatine is 85. | What is the electron configuration of astatine? → Astatine has the electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵. | What is astatine used for? → Astatine is used mainly in research, especially At-211 targeted alpha therapy and heavy-halogen chemistry. ### Radon (Rn) — https://ferrumone.com/en/element/radon Atom no: 86 | Noble Gas | Period 6, Group 18 **Title:** Radon: Atomic Number, Uses and Isotopes **Description:** Radon element guide: atomic number 86, symbol Rn, atomic mass 222, electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶, radon-222 and lung cancer risk. **Keywords:** radon element, radon atomic number, radon electron configuration, radon uses, radon isotopes, radon 222, radon lung cancer, radioactive noble gas, radon testing **Properties:** atomic mass 222 u; electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶; state Gas - **History:** Radon was discovered in 1900 by Friedrich Ernst Dorn as a radioactive gas released from radium compounds. It was once called radium emanation before the name radon was adopted. - **Isotopes:** Radon-219, t½=About 4 seconds, Actinium-series isotope, sometimes called actinon.; Radon-220, t½=About 56 seconds, Thorium-series isotope, historically called thoron.; Radon-222, t½=About 3.8 days, Most important environmental radon isotope from radium-226 decay. - **Compounds:** RnF₂ (Radon Difluoride) - **Uses:** Radon testing and mitigation in homes and buildings; Geological and groundwater tracing research; Historical radon seed radiotherapy, now replaced by better-controlled sources; Earthquake and soil-gas research, although not a reliable prediction method - **Biology:** Radon has no biological role. Radon-222 and its short-lived decay products can be inhaled, deposit in the lungs and increase lung cancer risk through alpha radiation. - **Interesting:** Radon is colorless and odorless, so testing is needed to know whether indoor levels are elevated. Radon is often cited as the second leading cause of lung cancer after smoking. Radon-222 comes from uranium decay through radium-226 in rocks and soils. Although radon is a noble gas, heavy noble gas chemistry allows compounds such as radon difluoride under special conditions. - **Study notes:** Radon has atomic number 86 and symbol Rn. Its electron configuration is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶. Radon is a radioactive noble gas. Remember Rn-222 for indoor air risk and uranium-radium decay chains. - **FAQ:** What is the atomic number of radon? → The atomic number of radon is 86. | What is the electron configuration of radon? → Radon has the electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶. | What is radon used for? → Radon has limited modern uses; it is mainly important for testing, mitigation, environmental tracing and historical radiotherapy context. ### Francium (Fr) — https://ferrumone.com/en/element/francium Atom no: 87 | Alkali Metal | Period 7, Group 1 **Title:** Francium: Atomic Number, Uses and Isotopes **Description:** Francium element guide: atomic number 87, symbol Fr, atomic mass 223, electron configuration [Rn] 7s¹, francium-223, rarity and uses. **Keywords:** francium element, francium atomic number, francium electron configuration, francium uses, francium isotopes, francium 223, second rarest natural element, radioactive alkali metal, francium half life **Properties:** atomic mass 223 u; electron configuration [Rn] 7s¹; state Solid; electronegativity 0.7 - **History:** Francium was discovered in 1939 by Marguerite Perey at the Curie Institute while studying actinium decay products. It was named after France. - **Isotopes:** Francium-221, t½=About 4.9 minutes, Short-lived radioactive francium isotope used in research contexts.; Francium-223, t½=About 22 minutes, Longest-lived naturally occurring francium isotope from actinium decay. - **Uses:** Atomic physics experiments with trapped and laser-cooled francium atoms; Parity nonconservation and weak-interaction studies; Spectroscopy tests of heavy alkali metal electronic structure; Trace radiochemistry research rather than practical bulk applications - **Biology:** Francium has no biological role. All francium isotopes are radioactive and short-lived, and the element exists only in trace amounts. - **Interesting:** Francium is usually described as the second-rarest naturally occurring element after astatine, with only tens of grams estimated to exist in Earth’s crust at any moment. Francium should be extremely reactive as an alkali metal, but its short half-life prevents ordinary bulk chemistry. Marguerite Perey discovered francium while working on actinium, connecting element 87 directly to natural radioactive decay. Francium is studied atom by atom rather than in visible metal samples. - **Study notes:** Francium has atomic number 87 and symbol Fr. Its electron configuration is [Rn] 7s¹. Francium is a radioactive alkali metal. Remember Fr-223 for a 22-minute half-life and francium as the second-rarest naturally occurring element after astatine. - **FAQ:** What is the atomic number of francium? → The atomic number of francium is 87. | What is the electron configuration of francium? → Francium has the electron configuration [Rn] 7s¹. | What is francium used for? → Francium has no practical bulk uses; it is used in specialized atomic physics and spectroscopy research. ### Radium (Ra) — https://ferrumone.com/en/element/radium Atom no: 88 | Alkaline Earth Metal | Period 7, Group 2 **Title:** Radium: Atomic Number, Uses and Isotopes **Description:** Radium element guide: atomic number 88, symbol Ra, atomic mass 226, electron configuration [Rn] 7s², Ra-223, Ra-226 and isotopes. **Keywords:** radium element, radium atomic number, radium electron configuration, radium uses, radium isotopes, radium 223, radium 226, Radium Girls, Xofigo radium **Properties:** atomic mass 226 u; electron configuration [Rn] 7s²; state Solid; electronegativity 0.9 - **History:** Radium was discovered in 1898 by Marie Curie and Pierre Curie while processing uranium ore residues. Its name comes from the Latin radius, meaning ray, because of its intense radioactivity. - **Isotopes:** Radium-223, t½=About 11.4 days, Alpha-emitting isotope used as radium-223 dichloride in nuclear medicine.; Radium-226, t½=About 1600 years, Important natural radium isotope and parent of radon-222.; Radium-228, t½=About 5.75 years, Thorium-series beta-emitting radium isotope. - **Compounds:** RaCl₂ (Radium Chloride), RaBr₂ (Radium Bromide), RaSO₄ (Radium Sulfate) - **Uses:** Radium-223 dichloride for treating certain prostate cancers with bone metastases; Historical luminous paints for clocks, watches and aircraft instruments; Historical radium-beryllium neutron sources; Research and calibration contexts, now replaced by safer controlled sources in many applications - **Biology:** Radium has no biological role. Chemically it resembles calcium and can deposit in bone, where radioactive decay can damage tissue. - **Interesting:** Radium-226 decays to radon-222, connecting radium chemistry to indoor radon risk. The Radium Girls case helped shape occupational safety law and public understanding of radiation hazards. Radium salts glow in the dark only when mixed with phosphors; radium itself provides the radiation energy. Marie Curie received the 1911 Nobel Prize in Chemistry for work including radium and polonium. - **Study notes:** Radium has atomic number 88 and symbol Ra. Its electron configuration is [Rn] 7s². Radium is a radioactive alkaline earth metal. Remember Ra-226 for radon production and Ra-223 for targeted alpha therapy in bone metastases. - **FAQ:** What is the atomic number of radium? → The atomic number of radium is 88. | What is the electron configuration of radium? → Radium has the electron configuration [Rn] 7s². | What is radium used for? → Modern radium use is limited, but radium-223 is used in nuclear medicine and radium was historically used in luminous paint and neutron sources. ### Actinium (Ac) — https://ferrumone.com/en/element/actinium Atom no: 89 | Actinide | Period 7, f-block **Title:** Actinium: Atomic Number, Uses and Isotopes **Description:** Actinium element guide: atomic number 89, symbol Ac, atomic mass 227, electron configuration [Rn] 6d¹ 7s², Ac-225 therapy and isotopes. **Keywords:** actinium element, actinium atomic number, actinium electron configuration, actinium uses, actinium isotopes, actinium 225, Ac-225 targeted alpha therapy, actinium 227, actinide series **Properties:** atomic mass 227 u; electron configuration [Rn] 6d¹ 7s²; state Solid; electronegativity 1.1 - **History:** Actinium was discovered in 1899 by André-Louis Debierne in uranium ore residues, with independent work by Friedrich Oskar Giesel soon after. Its name comes from Greek aktis, meaning ray or beam. - **Isotopes:** Actinium-225, t½=About 9.92 days, Alpha-emitting isotope studied and used in targeted alpha therapy radiopharmaceuticals.; Actinium-227, t½=About 21.8 years, Naturally occurring isotope in the uranium-235 decay series. - **Compounds:** AcCl₃ (Actinium(III) Chloride), [²²⁵Ac]Ac-PSMA-617 (Actinium-225 PSMA), Ac₂O₃ (Actinium(III) Oxide) - **Uses:** Actinium-225 targeted alpha therapy research and clinical radiopharmaceutical development; Actinium-225 to bismuth-213 generator systems; Historical actinium-beryllium neutron source research; Fundamental actinide chemistry and radiochemistry studies - **Biology:** Actinium has no biological role and all isotopes are radioactive. Actinium-225 radioconjugates are being developed for targeted alpha therapy in nuclear medicine. - **Interesting:** Actinium gives its name to the actinide series, although early actinide chemistry often resembles lanthanum chemistry. Actinium-225 decay can release multiple alpha particles through its decay chain. Actinium glows faintly in the dark because radiation excites surrounding air and materials. Ac-225 supply is a major practical challenge for expanding targeted alpha therapy research. - **Study notes:** Actinium has atomic number 89 and symbol Ac. Its electron configuration is [Rn] 6d¹ 7s². Actinium commonly forms +3 compounds. Remember Ac-225 for targeted alpha therapy and Ac-227 for the natural decay series. - **FAQ:** What is the atomic number of actinium? → The atomic number of actinium is 89. | What is the electron configuration of actinium? → Actinium has the electron configuration [Rn] 6d¹ 7s². | What is actinium used for? → Actinium is used mainly in radiopharmaceutical research, especially Ac-225 targeted alpha therapy, and in actinide chemistry studies. ### Thorium (Th) — https://ferrumone.com/en/element/thorium Atom no: 90 | Actinide | Period 7, f-block **Title:** Thorium: Atomic Number, Uses and Isotopes **Description:** Thorium element guide: atomic number 90, symbol Th, atomic mass 232.04, electron configuration [Rn] 6d² 7s², thorium-232, fuel cycle and isotopes. **Keywords:** thorium element, thorium atomic number, thorium electron configuration, thorium uses, thorium isotopes, thorium 232, thorium fuel cycle, uranium 233, Welsbach mantle **Properties:** atomic mass 232.04 u; electron configuration [Rn] 6d² 7s²; state Solid; electronegativity 1.3 - **History:** Thorium was discovered in 1829 by Jöns Jacob Berzelius in a Norwegian mineral and named after Thor, the Norse god of thunder. Thorium minerals such as monazite are important natural sources. - **Isotopes:** Thorium-230, t½=About 75,400 years, Natural uranium-series isotope used in U-Th dating contexts.; Thorium-232, Nearly 100%, t½=About 1.4 x 10¹⁰ years, Main natural thorium isotope and fertile material for the thorium fuel cycle. - **Compounds:** ThO₂ (Thorium Dioxide), ThF₄ (Thorium(IV) Fluoride), ThSiO₄ (Thorite) - **Uses:** Thorium fuel cycle research, where thorium-232 can breed fissile uranium-233; Thorium dioxide ceramics with very high melting point; Historical Welsbach gas mantles made from thorium and cerium oxides; Thoriated tungsten welding electrodes, now often replaced by safer alternatives; Thorium fluoride and oxide optical or high-temperature material research - **Biology:** Thorium has no biological role. Thorium-232 is a long-lived alpha emitter, and inhaled thorium compounds or historical Thorotrast exposure can pose serious health risks. - **Interesting:** Thorium is more abundant in Earth’s crust than uranium, but it is not directly fissile. In the thorium fuel cycle, Th-232 absorbs a neutron and ultimately produces fissile U-233. Welsbach mantles helped make gas lighting much brighter before electric lighting became dominant. Thorotrast, a historical thorium dioxide contrast agent, was abandoned after long-term cancer risks became clear. - **Study notes:** Thorium has atomic number 90 and symbol Th. Its electron configuration is [Rn] 6d² 7s². The common oxidation state is +4. Remember thorium for Th-232, U-233 breeding and the thorium fuel cycle. - **FAQ:** What is the atomic number of thorium? → The atomic number of thorium is 90. | What is the electron configuration of thorium? → Thorium has the electron configuration [Rn] 6d² 7s². | What is thorium used for? → Thorium is used or studied in nuclear fuel cycles, high-temperature ceramics, historical gas mantles, thoriated electrodes and optical materials. ### Protactinium (Pa) — https://ferrumone.com/en/element/protactinium Atom no: 91 | Actinide | Period 7, f-block **Title:** Protactinium: Atomic Number, Uses and Isotopes **Description:** Protactinium element guide: atomic number 91, symbol Pa, atomic mass 231.04, electron configuration [Rn] 5f² 6d¹ 7s², Pa-231 and isotopes. **Keywords:** protactinium element, protactinium atomic number, protactinium electron configuration, protactinium uses, protactinium isotopes, protactinium 231, Pa-231 Th-230 dating, uranium decay chain **Properties:** atomic mass 231.04 u; electron configuration [Rn] 5f² 6d¹ 7s²; state Solid; electronegativity 1.5 - **History:** The longer-lived isotope protactinium-231 was discovered in uranium minerals in 1917-1918 by Lise Meitner and Otto Hahn, with related independent work by Frederick Soddy, John Cranston and Alexander Fleck. The name means parent of actinium because Pa-231 decays toward actinium-227. - **Isotopes:** Protactinium-231, t½=About 32,760 years, Longest-lived natural protactinium isotope in the uranium-235 decay series.; Protactinium-234, t½=About 6.7 hours, Short-lived uranium-series isotope important in decay-chain studies. - **Compounds:** Pa₂O₅ (Protactinium(V) Oxide), PaCl₅ (Protactinium(V) Chloride), PaF₅ (Protactinium(V) Fluoride) - **Uses:** Pa-231/Th-230 isotope ratios in marine sediment and carbonate dating research; Tracer studies of ocean circulation and particle scavenging; Fundamental actinide chemistry and 5f-electron behavior research; Nuclear data studies connected to uranium decay chains - **Biology:** Protactinium has no biological role. All protactinium isotopes are radioactive, and Pa-231 is radiotoxic because it emits alpha radiation and has a long half-life. - **Interesting:** Protactinium is one of the rarest naturally occurring actinides in Earth’s crust. Pa-231/Th-230 ratios help reconstruct past ocean processes and sedimentation history. Protactinium sits between thorium and uranium, making it a useful case for studying early actinide chemistry. - **Study notes:** Protactinium has atomic number 91 and symbol Pa. Its electron configuration is [Rn] 5f² 6d¹ 7s². The +5 oxidation state is especially important. Remember Pa-231 for uranium-series decay and marine sediment dating. - **FAQ:** What is the atomic number of protactinium? → The atomic number of protactinium is 91. | What is the electron configuration of protactinium? → Protactinium has the electron configuration [Rn] 5f² 6d¹ 7s². | What is protactinium used for? → Protactinium has no broad commercial use; it is used mainly in geochronology, ocean-tracer and actinide chemistry research. ### Uranium (U) — https://ferrumone.com/en/element/uranium Atom no: 92 | Actinide | Period 7, f-block **Title:** Uranium: Atomic Number, Uses and Isotopes **Description:** Uranium element guide: atomic number 92, symbol U, atomic mass 238.03, electron configuration [Rn] 5f³ 6d¹ 7s², U-235, U-238 and uses. **Keywords:** uranium element, uranium atomic number, uranium electron configuration, uranium uses, uranium isotopes, uranium 235, uranium 238, uranium enrichment, U-Pb dating, depleted uranium **Properties:** atomic mass 238.03 u; electron configuration [Rn] 5f³ 6d¹ 7s²; state Solid; electronegativity 1.38 - **History:** Uranium was discovered in 1789 by Martin Heinrich Klaproth and named after the planet Uranus. Henri Becquerel discovered radioactivity in 1896 while studying uranium salts, and uranium later became central to nuclear energy and nuclear weapons. - **Isotopes:** Uranium-234, About 0.005%, t½=About 245,000 years, Minor natural isotope in the uranium-238 decay chain.; Uranium-235, About 0.72%, t½=About 7.04 x 10⁸ years, Naturally occurring fissile isotope used in reactors and weapons.; Uranium-238, About 99.27%, t½=About 4.47 x 10⁹ years, Dominant natural uranium isotope; fertile isotope that can breed plutonium-239. - **Compounds:** UO₂ (Uranium Dioxide), UF₆ (Uranium Hexafluoride), U₃O₈ (Triuranium Octoxide) - **Uses:** Uranium dioxide fuel pellets for nuclear reactors; Uranium-235 fission in reactors and nuclear weapons; U-Pb geochronology for dating zircon, meteorites and ancient rocks; Uranium hexafluoride in isotope enrichment processes; Depleted uranium for dense shielding and some armor-penetrating munitions - **Biology:** Uranium has no essential biological role. Its chemical toxicity, especially to the kidneys, and its radiological hazard both matter in exposure assessment. - **Interesting:** Becquerel’s work with uranium salts led to the discovery of radioactivity. Natural uranium is mostly U-238; the fissile U-235 isotope is less than 1%. U-Pb dating is one of the most important tools for determining the age of Earth’s oldest rocks. Uranium glass can fluoresce green under ultraviolet light. - **Study notes:** Uranium has atomic number 92 and symbol U. Its electron configuration is [Rn] 5f³ 6d¹ 7s². U-235 is fissile; U-238 is fertile. Remember uranium for nuclear fuel, enrichment, radioactivity and U-Pb dating. - **FAQ:** What is the atomic number of uranium? → The atomic number of uranium is 92. | What is the electron configuration of uranium? → Uranium has the electron configuration [Rn] 5f³ 6d¹ 7s². | What is uranium used for? → Uranium is used in nuclear fuel, isotope dating, enrichment chemistry, dense shielding and some military materials. ### Neptunium (Np) — https://ferrumone.com/en/element/neptunium Atom no: 93 | Actinide | Period 7, f-block **Title:** Neptunium: Atomic Number, Uses and Isotopes **Description:** Neptunium element guide: atomic number 93, symbol Np, atomic mass 237, electron configuration [Rn] 5f⁴ 6d¹ 7s², Np-237 and uses. **Keywords:** neptunium element, neptunium atomic number, neptunium electron configuration, neptunium uses, neptunium isotopes, neptunium 237, neptunium 239, plutonium 238 production, first transuranium element **Properties:** atomic mass 237 u; electron configuration [Rn] 5f⁴ 6d¹ 7s²; state Solid; electronegativity 1.36 - **History:** Neptunium was discovered in 1940 by Edwin McMillan and Philip Abelson at Berkeley by bombarding uranium with neutrons. It was named after Neptune, the planet after Uranus, following the naming pattern from uranium. - **Isotopes:** Neptunium-237, t½=About 2.14 x 10⁶ years, Long-lived isotope important in nuclear waste and Pu-238 production.; Neptunium-239, t½=About 2.36 days, Beta-decays to plutonium-239 and was central to early transuranium work. - **Compounds:** NpO₂ (Neptunium(IV) Oxide), NpF₆ (Neptunium Hexafluoride), NpO₂⁺ (Neptunyl(V) Ion) - **Uses:** Neptunium-237 targets for producing plutonium-238 used in radioisotope power systems; Long-term nuclear waste behavior and transmutation research; Neutron detection and nuclear data studies; Fundamental actinide chemistry across multiple oxidation states - **Biology:** Neptunium has no biological role. Its isotopes are radioactive and require strict radiological controls, especially in nuclear waste and actinide handling contexts. - **Interesting:** Neptunium was the first element beyond uranium to be synthesized and identified. Np-237 can be separated from spent nuclear fuel and is a key long-lived actinide in waste studies. Pu-238 production for spacecraft power begins with neutron irradiation of Np-237 targets. - **Study notes:** Neptunium has atomic number 93 and symbol Np. Its electron configuration is [Rn] 5f⁴ 6d¹ 7s². Neptunium is the first transuranium element. Remember Np-237 for Pu-238 production and long-term nuclear waste research. - **FAQ:** What is the atomic number of neptunium? → The atomic number of neptunium is 93. | What is the electron configuration of neptunium? → Neptunium has the electron configuration [Rn] 5f⁴ 6d¹ 7s². | What is neptunium used for? → Neptunium is used mainly in nuclear research, especially Pu-238 production, waste studies and actinide chemistry. ### Plutonium (Pu) — https://ferrumone.com/en/element/plutonium Atom no: 94 | Actinide | Period 7, f-block **Title:** Plutonium: Atomic Number, Uses and Isotopes **Description:** Plutonium element guide: atomic number 94, symbol Pu, atomic mass 244, electron configuration [Rn] 5f⁶ 7s², Pu-238, Pu-239 and uses. **Keywords:** plutonium element, plutonium atomic number, plutonium electron configuration, plutonium uses, plutonium isotopes, plutonium 238, plutonium 239, RTG plutonium, MOX fuel, Fat Man plutonium **Properties:** atomic mass 244 u; electron configuration [Rn] 5f⁶ 7s²; state Solid; electronegativity 1.28 - **History:** Plutonium was synthesized in 1940-1941 by Glenn Seaborg, Edwin McMillan, Joseph Kennedy and Arthur Wahl. Plutonium-239 became a central material in the Manhattan Project and the Fat Man bomb used at Nagasaki. - **Isotopes:** Plutonium-238, t½=About 87.7 years, Alpha-emitting isotope used as a heat source in RTGs and radioisotope power systems.; Plutonium-239, t½=About 24,110 years, Fissile isotope used in nuclear weapons and reactor fuel contexts.; Plutonium-240, t½=About 6,560 years, Spontaneous fission makes it important in reactor-grade plutonium and safeguards. - **Compounds:** PuO₂ (Plutonium(IV) Oxide), Pu(NO₃)₄ (Plutonium(IV) Nitrate), PuF₆ (Plutonium Hexafluoride) - **Uses:** Plutonium-239 in nuclear weapons and some reactor fuel cycles; Mixed oxide fuel, or MOX fuel, made from plutonium oxide and uranium oxide; Plutonium-238 dioxide heat sources for spacecraft radioisotope power systems; Nuclear forensics, safeguards and long-term waste management research - **Biology:** Plutonium has no biological role and is highly radiotoxic if inhaled or ingested. Its alpha-emitting isotopes can deposit in bone and liver, requiring strict containment and safeguards. - **Interesting:** Pu-238 is chosen for many spacecraft power systems because it produces steady heat for decades. Pu-239 can sustain a fast-neutron chain reaction and is a major fissile isotope in nuclear weapons. Plutonium has complex allotropes and unusual metal behavior because of its 5f electrons. Managing separated plutonium is both a nuclear energy issue and a nuclear security issue. - **Study notes:** Plutonium has atomic number 94 and symbol Pu. Its electron configuration is [Rn] 5f⁶ 7s². Pu-239 is fissile; Pu-238 is used mainly as a heat source. Remember plutonium for nuclear weapons, MOX fuel, RTGs and safeguards. - **FAQ:** What is the atomic number of plutonium? → The atomic number of plutonium is 94. | What is the electron configuration of plutonium? → Plutonium has the electron configuration [Rn] 5f⁶ 7s². | What is plutonium used for? → Plutonium is used in nuclear weapons, some nuclear fuel cycles, RTG heat sources and nuclear research. ### Americium (Am) — https://ferrumone.com/en/element/americium Atom no: 95 | Actinide | Period 7, f-block **Title:** Americium: Atomic Number, Uses and Isotopes **Description:** Americium element guide: atomic number 95, symbol Am, atomic mass 243, electron configuration [Rn] 5f⁷ 7s², Am-241 smoke detectors and isotopes. **Keywords:** americium element, americium atomic number, americium electron configuration, americium uses, americium isotopes, americium 241, smoke detector americium, Am-241 half life **Properties:** atomic mass 243 u; electron configuration [Rn] 5f⁷ 7s²; state Solid; electronegativity 1.3 - **History:** Americium was synthesized in 1944 by Glenn Seaborg, Ralph James, Leon Morgan and Albert Ghiorso during the Manhattan Project. It was named after the Americas, by analogy with europium. - **Isotopes:** Americium-241, t½=About 432.2 years, Alpha emitter with weak gamma emission, widely used in ionization smoke detectors.; Americium-243, t½=About 7,370 years, Long-lived americium isotope used in heavy actinide research. - **Compounds:** AmO₂ (Americium Dioxide), AmCl₃ (Americium(III) Chloride) - **Uses:** Americium-241 in ionization-type smoke detectors; Industrial thickness, density and level gauges; Neutron sources when mixed with beryllium; Heavy actinide production and radiochemistry research - **Biology:** Americium has no biological role. Am-241 emits alpha particles and weak gamma radiation, so sealed sources are handled differently from internal contamination risks. - **Interesting:** A typical ionization smoke detector contains only a tiny sealed Am-241 source. Am-241 forms as plutonium-241 decays by beta emission. Americium’s 5f⁷ configuration is often compared with europium’s half-filled 4f shell. - **Study notes:** Americium has atomic number 95 and symbol Am. Its electron configuration is [Rn] 5f⁷ 7s². The +3 oxidation state is especially common. Remember Am-241 for ionization smoke detectors. - **FAQ:** What is the atomic number of americium? → The atomic number of americium is 95. | What is the electron configuration of americium? → Americium has the electron configuration [Rn] 5f⁷ 7s². | What is americium used for? → Americium is used in ionization smoke detectors, industrial gauges, neutron sources and actinide research. ### Curium (Cm) — https://ferrumone.com/en/element/curium Atom no: 96 | Actinide | Period 7, f-block **Title:** Curium: Atomic Number, Uses and Isotopes **Description:** Curium element guide: atomic number 96, symbol Cm, atomic mass 247, electron configuration [Rn] 5f⁷ 6d¹ 7s², Cm-244 APXS and isotopes. **Keywords:** curium element, curium atomic number, curium electron configuration, curium uses, curium isotopes, curium 244, Cm-244 APXS, Mars rover APXS, curium 242 **Properties:** atomic mass 247 u; electron configuration [Rn] 5f⁷ 6d¹ 7s²; state Solid; electronegativity 1.3 - **History:** Curium was synthesized in 1944 by Glenn Seaborg, Ralph James and Albert Ghiorso by bombarding plutonium with alpha particles. It was named after Marie Curie and Pierre Curie. - **Isotopes:** Curium-242, t½=About 163 days, High-specific-power alpha emitter studied for radioisotope power applications.; Curium-244, t½=About 18.1 years, Alpha source used in APXS instruments for planetary surface analysis.; Curium-248, t½=About 3.4 x 10⁵ years, Long-lived isotope used in heavy actinide research. - **Compounds:** CmO₂ (Curium Dioxide), CmCl₃ (Curium(III) Chloride) - **Uses:** Curium-244 alpha sources in Alpha Particle X-ray Spectrometers on Mars rovers; Curium isotopes in heavy actinide and superheavy element synthesis targets; Curium-242 and curium-244 radioisotope power research; Nuclear structure and actinide chemistry studies - **Biology:** Curium has no biological role and all isotopes are radioactive. Curium isotopes can be strongly radiotoxic if incorporated into the body. - **Interesting:** Curium is named after two pioneers of radioactivity, Marie and Pierre Curie. Cm-244 alpha particles can excite X-rays from a rock surface, letting APXS instruments measure composition. Curium is chemically similar in some ways to gadolinium because of the half-filled f-shell pattern. - **Study notes:** Curium has atomic number 96 and symbol Cm. Its electron configuration is [Rn] 5f⁷ 6d¹ 7s². Curium commonly forms +3 compounds. Remember Cm-244 for Mars rover APXS instruments. - **FAQ:** What is the atomic number of curium? → The atomic number of curium is 96. | What is the electron configuration of curium? → Curium has the electron configuration [Rn] 5f⁷ 6d¹ 7s². | What is curium used for? → Curium is used in APXS planetary instruments, actinide research, isotope power research and heavy element synthesis. ### Berkelium (Bk) — https://ferrumone.com/en/element/berkelium Atom no: 97 | Actinide | Period 7, f-block **Title:** Berkelium: Atomic Number, Uses and Isotopes **Description:** Berkelium element guide: atomic number 97, symbol Bk, atomic mass 247, electron configuration [Rn] 5f⁹ 7s², Bk-249 and tennessine synthesis. **Keywords:** berkelium element, berkelium atomic number, berkelium electron configuration, berkelium uses, berkelium isotopes, berkelium 249, tennessine synthesis, element 117 synthesis **Properties:** atomic mass 247 u; electron configuration [Rn] 5f⁹ 7s²; state Solid; electronegativity 1.3 - **History:** Berkelium was synthesized in 1949 by Stanley Thompson, Glenn Seaborg, Kenneth Street Jr. and Albert Ghiorso at Berkeley. It was named after Berkeley, California and the University of California, Berkeley. - **Isotopes:** Berkelium-247, t½=About 1,380 years, Long-lived berkelium isotope used in research discussions.; Berkelium-249, t½=About 330 days, Important target isotope used in the synthesis of tennessine. - **Compounds:** BkO₂ (Berkelium Dioxide), BkCl₃ (Berkelium(III) Chloride) - **Uses:** Berkelium-249 target material for synthesizing tennessine, element 117; Heavy actinide chemistry research; Studies of +3 and +4 oxidation states in late actinides; Production chains for heavier actinides and transactinides - **Biology:** Berkelium has no biological role. It is synthetic, radioactive and produced only in very small quantities for research. - **Interesting:** The tennessine discovery depended on a rare Bk-249 target produced at Oak Ridge and sent to Dubna. Only milligram or smaller quantities of berkelium are available for most research. Berkelium can show +4 chemistry more readily than many neighboring late actinides. - **Study notes:** Berkelium has atomic number 97 and symbol Bk. Its electron configuration is [Rn] 5f⁹ 7s². Berkelium is a synthetic actinide. Remember Bk-249 for tennessine, element 117, synthesis. - **FAQ:** What is the atomic number of berkelium? → The atomic number of berkelium is 97. | What is the electron configuration of berkelium? → Berkelium has the electron configuration [Rn] 5f⁹ 7s². | What is berkelium used for? → Berkelium is used mainly in heavy element synthesis and actinide chemistry research. ### Californium (Cf) — https://ferrumone.com/en/element/californium Atom no: 98 | Actinide | Period 7, f-block **Title:** Californium: Atomic Number, Uses and Isotopes **Description:** Californium element guide: atomic number 98, symbol Cf, atomic mass 251, electron configuration [Rn] 5f¹⁰ 7s², Cf-252 neutron source and isotopes. **Keywords:** californium element, californium atomic number, californium electron configuration, californium uses, californium isotopes, californium 252, Cf-252 neutron source, neutron activation analysis, reactor startup source **Properties:** atomic mass 251 u; electron configuration [Rn] 5f¹⁰ 7s²; state Solid; electronegativity 1.3 - **History:** Californium was synthesized in 1950 by Stanley Thompson, Kenneth Street Jr., Albert Ghiorso and Glenn Seaborg at Berkeley by bombarding curium with alpha particles. It was named after California and the University of California. - **Isotopes:** Californium-251, t½=About 898 years, Long-lived californium isotope.; Californium-252, t½=About 2.65 years, Important spontaneous-fission neutron source isotope. - **Compounds:** Cf₂O₃ (Californium(III) Oxide), CfCl₃ (Californium(III) Chloride) - **Uses:** Californium-252 neutron sources for reactor startup and calibration; Neutron activation analysis for material identification; Oil-well and mineral exploration logging tools; Portable neutron sources for security and industrial analysis; Specialized neutron brachytherapy research and historical clinical use - **Biology:** Californium has no biological role. Its neutron-emitting isotopes, especially Cf-252, require heavy shielding and strict radiation controls. - **Interesting:** One microgram of Cf-252 emits about 2.3 million neutrons per second. Californium is among the most expensive elements because it must be made in specialized nuclear reactors. Cf-252 is valuable because it provides a compact neutron source without a reactor. - **Study notes:** Californium has atomic number 98 and symbol Cf. Its electron configuration is [Rn] 5f¹⁰ 7s². Californium commonly forms +3 compounds. Remember Cf-252 for neutron sources and spontaneous fission. - **FAQ:** What is the atomic number of californium? → The atomic number of californium is 98. | What is the electron configuration of californium? → Californium has the electron configuration [Rn] 5f¹⁰ 7s². | What is californium used for? → Californium is used in neutron sources, reactor startup, neutron activation analysis, well logging and specialized research. ### Einsteinium (Es) — https://ferrumone.com/en/element/einsteinium Atom no: 99 | Actinide | Period 7, f-block **Title:** Einsteinium: Atomic Number, Uses and Isotopes **Description:** Einsteinium element guide: atomic number 99, symbol Es, atomic mass 252, electron configuration [Rn] 5f¹¹ 7s², Es-253 and discovery. **Keywords:** einsteinium element, einsteinium atomic number, einsteinium electron configuration, einsteinium uses, einsteinium isotopes, einsteinium 253, Ivy Mike einsteinium, mendelevium synthesis **Properties:** atomic mass 252 u; electron configuration [Rn] 5f¹¹ 7s²; state Solid; electronegativity 1.3 - **History:** Einsteinium was discovered by Albert Ghiorso and collaborators in debris from the 1952 Ivy Mike hydrogen bomb test. The discovery remained classified until 1955 and the element was named after Albert Einstein. - **Isotopes:** Einsteinium-252, t½=About 471.7 days, Longest-lived einsteinium isotope, available only in minute quantities.; Einsteinium-253, t½=About 20.5 days, Important isotope for research and mendelevium synthesis. - **Compounds:** EsCl₃ (Einsteinium(III) Chloride), Es₂O₃ (Einsteinium(III) Oxide) - **Uses:** Einsteinium-253 targets for synthesizing mendelevium; Spectroscopy of actinide f-electron behavior; Basic nuclear structure research; Preparation of heavier actinides in specialized facilities - **Biology:** Einsteinium has no biological role. It is intensely radioactive and produced only in extremely small quantities, so biological studies are very limited. - **Interesting:** Einsteinium and fermium were identified from the debris of the first full-scale thermonuclear test. Einsteinium-253 was used in the first synthesis of mendelevium. Einsteinium is produced in such tiny amounts that many measurements require atom-counting or trace chemistry methods. - **Study notes:** Einsteinium has atomic number 99 and symbol Es. Its electron configuration is [Rn] 5f¹¹ 7s². Einsteinium commonly forms +3 compounds. Remember Es for Ivy Mike discovery and mendelevium synthesis. - **FAQ:** What is the atomic number of einsteinium? → The atomic number of einsteinium is 99. | What is the electron configuration of einsteinium? → Einsteinium has the electron configuration [Rn] 5f¹¹ 7s². | What is einsteinium used for? → Einsteinium is used only in specialized research, including actinide spectroscopy and synthesis of heavier elements such as mendelevium. ### Fermium (Fm) — https://ferrumone.com/en/element/fermium Atom no: 100 | Actinide | Period 7, f-block **Title:** Fermium: Atomic Number, Uses and Isotopes **Description:** Fermium element guide: atomic number 100, symbol Fm, atomic mass 257, electron configuration [Rn] 5f¹² 7s², Fm-257 and discovery. **Keywords:** fermium element, fermium atomic number, fermium electron configuration, fermium uses, fermium isotopes, fermium 257, Ivy Mike fermium, fermium wall **Properties:** atomic mass 257 u; electron configuration [Rn] 5f¹² 7s²; state Solid; electronegativity 1.3 - **History:** Fermium was discovered by Albert Ghiorso and collaborators in debris from the 1952 Ivy Mike hydrogen bomb test. It was named after Enrico Fermi, who led the first controlled nuclear chain reaction. - **Isotopes:** Fermium-255, t½=About 20.1 hours, Short-lived isotope produced in reactor and nuclear research contexts.; Fermium-257, t½=About 100.5 days, Longest-lived fermium isotope and the main isotope for chemical research. - **Uses:** Fermium-257 in fundamental nuclear structure and actinide chemistry research; Studies of spontaneous fission and heavy nuclei; Research on the production limits of very heavy elements; Trace chemistry of late actinides - **Biology:** Fermium has no biological role. It is synthetic, radioactive and produced only in very small quantities for nuclear research. - **Interesting:** Fermium is often described as the heaviest element reached by neutron-capture production routes in reactors. The “fermium wall” describes the difficulty of building heavier elements by neutron capture because heavier fermium isotopes fission quickly. Fermium is named after Enrico Fermi, whose work marks the start of the controlled nuclear reactor era. - **Study notes:** Fermium has atomic number 100 and symbol Fm. Its electron configuration is [Rn] 5f¹² 7s². Fermium commonly forms +3 compounds in trace chemistry. Remember Fm-257 for the longest-lived fermium isotope and the fermium wall concept. - **FAQ:** What is the atomic number of fermium? → The atomic number of fermium is 100. | What is the electron configuration of fermium? → Fermium has the electron configuration [Rn] 5f¹² 7s². | What is fermium used for? → Fermium has no commercial use; it is used only in nuclear physics and actinide chemistry research. ### Mendelevium (Md) — https://ferrumone.com/en/element/mendelevium Atom no: 101 | Actinide | Period 7, f-block **Title:** Mendelevium: Atomic Number, Uses and Isotopes **Description:** Mendelevium element guide: atomic number 101, symbol Md, atomic mass 258, electron configuration [Rn] 5f¹³ 7s², Md-258 and discovery. **Keywords:** mendelevium element, mendelevium atomic number, mendelevium electron configuration, mendelevium uses, mendelevium isotopes, mendelevium 258, first atom by atom element, mendelevium oxidation states **Properties:** atomic mass 258 u; electron configuration [Rn] 5f¹³ 7s²; state Solid; electronegativity 1.3 - **History:** Mendelevium was synthesized in 1955 at Berkeley by Albert Ghiorso, Glenn Seaborg, Bernard Harvey, Gregory Choppin and Stanley Thompson by bombarding einsteinium-253 with alpha particles. The first experiment identified only a tiny number of atoms, making it a milestone in atom-by-atom chemistry. - **Isotopes:** Mendelevium-256, t½=About 77 minutes, Early synthesized mendelevium isotope from the first atom-by-atom discovery work.; Mendelevium-258, t½=About 51.5 days, Longest-lived mendelevium isotope and the most useful for chemical studies.; Mendelevium-260, t½=About 28 days, Long-lived isotope used in nuclear data discussions. - **Uses:** Trace actinide chemistry experiments on +2 and +3 oxidation states; Nuclear structure studies of late actinides; Production and identification methods for single atoms; Research on the transition from actinide to transactinide chemistry - **Biology:** Mendelevium has no biological role. It is synthetic, radioactive and produced only in extremely small quantities for nuclear and actinide chemistry research. - **Interesting:** Mendelevium is named after Dmitri Mendeleev, creator of the periodic table. Its first synthesis produced only atom-scale quantities, yet the atoms were chemically identified. Mendelevium can show a +2 oxidation state, a late-actinide feature related to f-electron stability. - **Study notes:** Mendelevium has atomic number 101 and symbol Md. Its electron configuration is [Rn] 5f¹³ 7s². Mendelevium is a synthetic actinide with no commercial use. Remember Md-258 for the longest-lived mendelevium isotope and atom-by-atom synthesis history. - **FAQ:** What is the atomic number of mendelevium? → The atomic number of mendelevium is 101. | What is the electron configuration of mendelevium? → Mendelevium has the electron configuration [Rn] 5f¹³ 7s². | What is mendelevium used for? → Mendelevium is used only in nuclear physics and trace actinide chemistry research. ### Nobelium (No) — https://ferrumone.com/en/element/nobelium Atom no: 102 | Actinide | Period 7, f-block **Title:** Nobelium: Atomic Number, Uses and Isotopes **Description:** Nobelium element guide: atomic number 102, symbol No, atomic mass 259, electron configuration [Rn] 5f¹⁴ 7s², No-259 and No²⁺ chemistry. **Keywords:** nobelium element, nobelium atomic number, nobelium electron configuration, nobelium uses, nobelium isotopes, nobelium 259, nobelium oxidation state, No2+ chemistry **Properties:** atomic mass 259 u; electron configuration [Rn] 5f¹⁴ 7s²; state Solid; electronegativity 1.3 - **History:** Nobelium discovery was disputed among groups in Stockholm, Berkeley and Dubna. The name honors Alfred Nobel and was retained after the long transfermium naming debates. - **Isotopes:** Nobelium-255, t½=About 3.1 minutes, Short-lived isotope used in nuclear studies.; Nobelium-259, t½=About 58 minutes, Longest-lived nobelium isotope. - **Uses:** Basic research on late-actinide chemistry; Studies of No²⁺ stability and the effect of a full 5f shell; Nuclear structure and decay-chain research - **Biology:** Nobelium has no biological role. It is produced only in particle accelerators and all of its isotopes are radioactive. - **Interesting:** Nobelium is unusual among actinides because the +2 oxidation state is especially stable in aqueous chemistry. No²⁺ has a full 5f¹⁴ configuration, analogous to the stability of Yb²⁺ in the lanthanides. The nobelium naming story is part of the transfermium wars over element discovery priority. - **Study notes:** Nobelium has atomic number 102 and symbol No. Its electron configuration is [Rn] 5f¹⁴ 7s². Nobelium often favors +2 chemistry because No²⁺ has a full 5f¹⁴ shell. Remember No-259 for a roughly 58-minute half-life. - **FAQ:** What is the atomic number of nobelium? → The atomic number of nobelium is 102. | What is the electron configuration of nobelium? → Nobelium has the electron configuration [Rn] 5f¹⁴ 7s². | What is nobelium used for? → Nobelium has no commercial use; it is used only in nuclear and actinide chemistry research. ### Lawrencium (Lr) — https://ferrumone.com/en/element/lawrencium Atom no: 103 | Actinide | Period 7, f-block **Title:** Lawrencium: Atomic Number, Uses and Isotopes **Description:** Lawrencium element guide: atomic number 103, symbol Lr, atomic mass 262, electron configuration [Rn] 5f¹⁴ 7s² 7p¹, Lr isotopes and uses. **Keywords:** lawrencium element, lawrencium atomic number, lawrencium electron configuration, lawrencium uses, lawrencium isotopes, lawrencium 7p1, lawrencium ionization energy, last actinide **Properties:** atomic mass 262 u; electron configuration [Rn] 5f¹⁴ 7s² 7p¹; state Solid; electronegativity 1.3 - **History:** Lawrencium was first reported in 1961 by the Berkeley team and named after Ernest O. Lawrence, inventor of the cyclotron. It closes the actinide series. - **Isotopes:** Lawrencium-256, t½=About 27 seconds, Isotope used in the 2015 first-ionization-energy measurement experiment.; Lawrencium-262, t½=About 3.6 hours, Long-lived isotope often listed in reference tables.; Lawrencium-266, t½=About 22 hours, Among the longest-lived lawrencium isotopes; reported uncertainty is large. - **Uses:** Testing relativistic electronic-structure calculations; Ionization energy and actinide-series boundary research; Nuclear decay and heavy-ion reaction studies - **Biology:** Lawrencium has no biological role. It is synthetic, radioactive and produced atom by atom for research. - **Interesting:** Lawrencium’s ground-state electron configuration is [Rn] 5f¹⁴ 7s² 7p¹ rather than the simple 6d¹ expectation. Its first ionization energy measurement helped confirm theoretical predictions about relativistic effects. Lawrencium is the final actinide, but its 7p¹ electron makes its placement chemically interesting. - **Study notes:** Lawrencium has atomic number 103 and symbol Lr. Its electron configuration is [Rn] 5f¹⁴ 7s² 7p¹. Lawrencium marks the end of the actinide series. Remember Lr for relativistic 7p¹ electron configuration. - **FAQ:** What is the atomic number of lawrencium? → The atomic number of lawrencium is 103. | What is the electron configuration of lawrencium? → Lawrencium has the electron configuration [Rn] 5f¹⁴ 7s² 7p¹. | What is lawrencium used for? → Lawrencium is used only in nuclear physics and relativistic electronic-structure research. ### Rutherfordium (Rf) — https://ferrumone.com/en/element/rutherfordium Atom no: 104 | Transition Metal | Period 7, Group 4 **Title:** Rutherfordium: Atomic Number, Uses and Isotopes **Description:** Rutherfordium element guide: atomic number 104, symbol Rf, atomic mass 267, predicted electron configuration [Rn] 5f¹⁴ 6d² 7s², Rf isotopes and chemistry. **Keywords:** rutherfordium element, rutherfordium atomic number, rutherfordium electron configuration, rutherfordium uses, rutherfordium isotopes, rutherfordium 267, rutherfordium chloride, transactinide element, Group 4 chemistry **Properties:** atomic mass 267 u; electron configuration [Rn] 5f¹⁴ 6d² 7s²; state Solid - **History:** Rutherfordium was claimed by both JINR Dubna and Berkeley during the transfermium naming disputes. The final IUPAC name honors Ernest Rutherford, a founder of nuclear physics. - **Isotopes:** Rutherfordium-261, t½=About 1 minute, Short-lived isotope with reported long-lived states used in early studies.; Rutherfordium-267, t½=About 1-2.5 hours, One of the longer-lived rutherfordium isotopes; reported values vary by nuclear data source. - **Compounds:** RfCl₄ (Rutherfordium(IV) Chloride), RfF₆²⁻ (Hexafluororutherfordate Complex) - **Uses:** Gas-phase chloride chemistry comparing Rf with zirconium and hafnium; Aqueous Group 4 chemistry research; Testing relativistic effects in transactinide elements; Nuclear decay-chain identification studies - **Biology:** Rutherfordium has no biological role. It is synthetic, highly radioactive and exists only as short-lived atoms in laboratory experiments. - **Interesting:** Rutherfordium begins the transactinide region and period 7 transition-metal chemistry. Its chemistry broadly follows Group 4 behavior but can show relativistic deviations from zirconium and hafnium trends. The rutherfordium naming dispute was one of the central episodes in the transfermium wars. - **Study notes:** Rutherfordium has atomic number 104 and symbol Rf. Its listed electron configuration is [Rn] 5f¹⁴ 6d² 7s²; superheavy element values are partly prediction-based. Rutherfordium is a Group 4 transactinide below hafnium. Remember RfCl₄ and Group 4 chemistry comparisons. - **FAQ:** What is the atomic number of rutherfordium? → The atomic number of rutherfordium is 104. | What is the electron configuration of rutherfordium? → Rutherfordium is commonly listed with [Rn] 5f¹⁴ 6d² 7s², but superheavy-element values should be treated as partly prediction-based. | What is rutherfordium used for? → Rutherfordium has no commercial use; it is used in transactinide chemistry and nuclear physics research. ### Dubnium (Db) — https://ferrumone.com/en/element/dubnium Atom no: 105 | Transition Metal | Period 7, Group 5 **Title:** Dubnium: Atomic Number, Uses and Isotopes **Description:** Dubnium element guide: atomic number 105, symbol Db, atomic mass 268, predicted electron configuration [Rn] 5f¹⁴ 6d³ 7s², Db isotopes and chemistry. **Keywords:** dubnium element, dubnium atomic number, dubnium electron configuration, dubnium uses, dubnium isotopes, dubnium 268, dubnium chemistry, Group 5 transactinide, transfermium wars **Properties:** atomic mass 268 u; electron configuration [Rn] 5f¹⁴ 6d³ 7s²; state Solid - **History:** Dubnium was involved in discovery and naming disputes between Dubna and Berkeley. The official name honors Dubna, Russia, home of the Joint Institute for Nuclear Research. - **Isotopes:** Dubnium-268, t½=About 29-32 hours, Longest-lived known dubnium isotope in current nuclear data discussions.; Dubnium-270, t½=About 1-2 hours, Short-lived isotope observed in superheavy decay chains. - **Compounds:** DbF₅ (Dubnium(V) Fluoride), DbCl₅ (Dubnium(V) Chloride) - **Uses:** Transactinide aqueous chemistry comparing Db with niobium and tantalum; Studies of Group 5 fluoride and chloride complex behavior; Relativistic chemistry tests in superheavy elements; Nuclear decay-chain research - **Biology:** Dubnium has no biological role. It is synthetic, radioactive and too short-lived for any practical biological interaction. - **Interesting:** Dubnium chemistry is especially useful for testing whether Group 5 trends continue below tantalum. Some dubnium chemistry results differ from simple niobium-tantalum extrapolation, making relativistic effects important. The element name preserves the role of Dubna in superheavy element research. - **Study notes:** Dubnium has atomic number 105 and symbol Db. Its listed electron configuration is [Rn] 5f¹⁴ 6d³ 7s²; superheavy element values are partly prediction-based. Dubnium is a Group 5 transactinide below tantalum. Remember Db for transfermium naming history and Group 5 chemistry tests. - **FAQ:** What is the atomic number of dubnium? → The atomic number of dubnium is 105. | What is the electron configuration of dubnium? → Dubnium is commonly listed with [Rn] 5f¹⁴ 6d³ 7s², but superheavy-element values should be treated as partly prediction-based. | What is dubnium used for? → Dubnium is used only in transactinide chemistry and nuclear physics research. ### Seaborgium (Sg) — https://ferrumone.com/en/element/seaborgium Atom no: 106 | Transition Metal | Period 7, Group 6 **Title:** Seaborgium: Atomic Number, Uses and Isotopes **Description:** Seaborgium element guide: atomic number 106, symbol Sg, atomic mass 271, predicted electron configuration [Rn] 5f¹⁴ 6d⁴ 7s², Sg chemistry and isotopes. **Keywords:** seaborgium element, seaborgium atomic number, seaborgium electron configuration, seaborgium uses, seaborgium isotopes, seaborgium 269, SgO2Cl2, Glenn Seaborg element, Group 6 transactinide **Properties:** atomic mass 271 u; electron configuration [Rn] 5f¹⁴ 6d⁴ 7s²; state Solid - **History:** Seaborgium was synthesized in 1974 by the Berkeley team and named after Glenn T. Seaborg. It became one of the rare elements named after a living person at the time the name was approved. - **Isotopes:** Seaborgium-269, t½=About 5 minutes, One of the longer-lived seaborgium isotopes in current nuclear data.; Seaborgium-271, t½=About 2-2.4 minutes, Commonly cited seaborgium isotope used in reference tables. - **Compounds:** SgO₂Cl₂ (Seaborgium Dioxide Dichloride), SgO₂(OH)₂ (Seaborgium Oxide Hydroxide) - **Uses:** Gas-phase chemistry of seaborgium oxychlorides; Group 6 transactinide comparisons with molybdenum and tungsten; Testing relativistic effects in superheavy chemistry; Nuclear decay studies - **Biology:** Seaborgium has no biological role. It is synthetic, highly radioactive and produced only atom by atom. - **Interesting:** Seaborgium honors Glenn Seaborg, who helped discover several transuranium elements. SgO₂Cl₂ chemistry supports seaborgium’s placement in Group 6 below tungsten. Naming an element after a living scientist was controversial during the transfermium naming debates. - **Study notes:** Seaborgium has atomic number 106 and symbol Sg. Its listed electron configuration is [Rn] 5f¹⁴ 6d⁴ 7s²; superheavy element values are partly prediction-based. Seaborgium is a Group 6 transactinide below tungsten. Remember SgO₂Cl₂ for gas-phase chemistry confirmation. - **FAQ:** What is the atomic number of seaborgium? → The atomic number of seaborgium is 106. | What is the electron configuration of seaborgium? → Seaborgium is commonly listed with [Rn] 5f¹⁴ 6d⁴ 7s², but superheavy-element values should be treated as partly prediction-based. | What is seaborgium used for? → Seaborgium is used only in nuclear physics and transactinide chemistry research. ### Bohrium (Bh) — https://ferrumone.com/en/element/bohrium Atom no: 107 | Transition Metal | Period 7, Group 7 **Title:** Bohrium: Atomic Number, Uses and Isotopes **Description:** Bohrium element guide: atomic number 107, symbol Bh, atomic mass 270, predicted electron configuration [Rn] 5f¹⁴ 6d⁵ 7s², Bh isotopes and chemistry. **Keywords:** bohrium element, bohrium atomic number, bohrium electron configuration, bohrium uses, bohrium isotopes, bohrium 270, bohrium oxychloride, BhO3Cl, Group 7 transactinide **Properties:** atomic mass 270 u; electron configuration [Rn] 5f¹⁴ 6d⁵ 7s²; state Solid - **History:** Bohrium was synthesized in 1981 at GSI Darmstadt by a team led by Peter Armbruster and Gottfried Münzenberg. It was named after Niels Bohr. - **Isotopes:** Bohrium-270, t½=About 1-4 minutes, Among the longer-lived known bohrium isotopes; reported values vary by nuclear data source and state.; Bohrium-274, t½=About 44-57 seconds, Observed in decay chains of heavier superheavy elements. - **Compounds:** BhO₃Cl (Bohrium Oxychloride) - **Uses:** Gas-phase chemistry testing Group 7 behavior; Bohrium oxychloride comparison with rhenium oxychloride; Nuclear decay-chain and heavy-ion reaction research - **Biology:** Bohrium has no biological role. It is synthetic, radioactive and exists only as short-lived atoms. - **Interesting:** Bohrium chemistry experiments support its behavior as a heavier homolog of rhenium. Only a handful of bohrium atoms are needed in experiments that test Group 7 chemistry. The element name honors Niels Bohr’s role in atomic structure and nuclear physics. - **Study notes:** Bohrium has atomic number 107 and symbol Bh. Its listed electron configuration is [Rn] 5f¹⁴ 6d⁵ 7s²; superheavy element values are partly prediction-based. Bohrium is a Group 7 transactinide below rhenium. Remember BhO₃Cl for gas-phase chemistry evidence. - **FAQ:** What is the atomic number of bohrium? → The atomic number of bohrium is 107. | What is the electron configuration of bohrium? → Bohrium is commonly listed with [Rn] 5f¹⁴ 6d⁵ 7s², but superheavy-element values should be treated as partly prediction-based. | What is bohrium used for? → Bohrium is used only in superheavy element research and gas-phase transactinide chemistry. ### Hassium (Hs) — https://ferrumone.com/en/element/hassium Atom no: 108 | Transition Metal | Period 7, Group 8 **Title:** Hassium: Atomic Number, Uses and Isotopes **Description:** Hassium element guide: atomic number 108, symbol Hs, atomic mass 277, predicted electron configuration [Rn] 5f¹⁴ 6d⁶ 7s², HsO₄ and isotopes. **Keywords:** hassium element, hassium atomic number, hassium electron configuration, hassium uses, hassium isotopes, hassium tetroxide, HsO4, osmium tetroxide analog, Group 8 transactinide **Properties:** atomic mass 277 u; electron configuration [Rn] 5f¹⁴ 6d⁶ 7s²; state Solid - **History:** Hassium was synthesized in 1984 at GSI Darmstadt. Its name comes from Hassia, the Latin name for Hesse, the German state where GSI is located. - **Isotopes:** Hassium-269, t½=About 10-16 seconds, Short-lived isotope used in hassium chemistry discussions.; Hassium-270, t½=About 18-22 seconds, Isotope used in early hassium tetroxide chemistry experiments.; Hassium-277m, t½=About 130 seconds, Metastable state among the longer-lived reported hassium states; values vary by source. - **Compounds:** HsO₄ (Hassium Tetroxide) - **Uses:** Gas-phase chemistry of hassium tetroxide; Testing Group 8 analogies with osmium and ruthenium; Relativistic chemistry and volatility studies; Nuclear decay-chain research - **Biology:** Hassium has no biological role. It is synthetic, radioactive and extremely short-lived. - **Interesting:** HsO₄ is one of the most famous compounds made from a superheavy element. Hassium tetroxide behaves broadly like osmium tetroxide, but measured adsorption data indicate HsO₄ is less volatile than OsO₄. The name hassium honors Hesse, the German state where the element was synthesized. - **Study notes:** Hassium has atomic number 108 and symbol Hs. Its listed electron configuration is [Rn] 5f¹⁴ 6d⁶ 7s²; superheavy element values are partly prediction-based. Hassium is a Group 8 transactinide below osmium. Remember HsO₄ as the osmium tetroxide analog. - **FAQ:** What is the atomic number of hassium? → The atomic number of hassium is 108. | What is the electron configuration of hassium? → Hassium is commonly listed with [Rn] 5f¹⁴ 6d⁶ 7s², but superheavy-element values should be treated as partly prediction-based. | What is hassium used for? → Hassium has no commercial use; it is used in superheavy element chemistry and nuclear research. ### Meitnerium (Mt) — https://ferrumone.com/en/element/meitnerium Atom no: 109 | Unknown | Period 7, Group 9 **Title:** Meitnerium: Atomic Number, Uses and Isotopes **Description:** Meitnerium element guide: atomic number 109, symbol Mt, atomic mass 278, calculated electron configuration [Rn] 5f¹⁴ 6d⁷ 7s², Mt isotopes and history. **Keywords:** meitnerium element, meitnerium atomic number, meitnerium electron configuration, meitnerium uses, meitnerium isotopes, meitnerium 278, Lise Meitner element, Group 9 transactinide **Properties:** atomic mass 278 u; electron configuration [Rn] 5f¹⁴ 6d⁷ 7s²; state Solid - **History:** Meitnerium was synthesized in 1982 at GSI Darmstadt by bombarding bismuth-209 with iron-58. It is named after Lise Meitner, whose work was central to understanding nuclear fission. - **Isotopes:** Meitnerium-278, t½=About 4.5-9 seconds, Among the longest-lived known meitnerium isotopes; values vary by nuclear data source. - **Uses:** Nuclear decay and superheavy element research; Theoretical Group 9 chemistry studies; Relativistic calculations comparing meitnerium with iridium - **Biology:** Meitnerium has no biological role. It is synthetic, radioactive and produced only atom by atom. - **Interesting:** Meitnerium is one of the few elements named after a woman scientist. No confirmed chemical compound of meitnerium has been experimentally characterized yet. The element name is often seen as a delayed recognition of Lise Meitner’s contribution to nuclear fission science. - **Study notes:** Meitnerium has atomic number 109 and symbol Mt. Its calculated electron configuration is [Rn] 5f¹⁴ 6d⁷ 7s². Meitnerium is predicted to be a Group 9 transactinide below iridium. Remember Mt for Lise Meitner and nuclear fission history. - **FAQ:** What is the atomic number of meitnerium? → The atomic number of meitnerium is 109. | What is the electron configuration of meitnerium? → Meitnerium is commonly listed with the calculated electron configuration [Rn] 5f¹⁴ 6d⁷ 7s². | What is meitnerium used for? → Meitnerium has no commercial use; it is used only in nuclear physics and theoretical chemistry research. ### Darmstadtium (Ds) — https://ferrumone.com/en/element/darmstadtium Atom no: 110 | Unknown | Period 7, Group 10 **Title:** Darmstadtium: Atomic Number, Uses and Isotopes **Description:** Darmstadtium element guide: atomic number 110, symbol Ds, atomic mass 281, source-dependent predicted electron configuration [Rn] 5f¹⁴ 6d⁹ 7s¹ and Ds isotopes. **Keywords:** darmstadtium element, darmstadtium atomic number, darmstadtium electron configuration, darmstadtium uses, darmstadtium isotopes, darmstadtium 281, GSI Darmstadt element, Group 10 transactinide, platinum analog **Properties:** atomic mass 281 u; electron configuration [Rn] 5f¹⁴ 6d⁹ 7s¹; state Solid - **History:** Darmstadtium was first synthesized in 1994 at GSI Darmstadt by bombarding lead with nickel ions. The element is named after Darmstadt, Germany, the city where GSI is located. - **Isotopes:** Darmstadtium-281, t½=About 13-14 seconds, Among the longest-lived known darmstadtium isotopes in common references. - **Uses:** Superheavy nuclear decay research; Theoretical Group 10 chemistry studies; Relativistic calculations comparing darmstadtium with platinum; Research connected to superheavy element stability trends - **Biology:** Darmstadtium has no biological role. It is synthetic, radioactive and extremely short-lived. - **Interesting:** Darmstadtium is predicted to be the heavier homolog of platinum in Group 10. Its predicted electron configuration is source-dependent: RSC-style tables commonly list [Rn] 5f¹⁴ 6d⁹ 7s¹, while some databases list [Rn] 5f¹⁴ 6d⁸ 7s². Only tiny numbers of darmstadtium atoms have ever been produced. Its name directly honors Darmstadt, a major center of superheavy element discovery. - **Study notes:** Darmstadtium has atomic number 110 and symbol Ds. Its electron configuration is listed as [Rn] 5f¹⁴ 6d⁹ 7s¹ in this periodic table data set, but superheavy-element predictions vary by source. Darmstadtium is a Group 10 transactinide below platinum. Remember Ds for GSI Darmstadt and superheavy element research. - **FAQ:** What is the atomic number of darmstadtium? → The atomic number of darmstadtium is 110. | What is the electron configuration of darmstadtium? → This data set lists darmstadtium with [Rn] 5f¹⁴ 6d⁹ 7s¹; some sources predict [Rn] 5f¹⁴ 6d⁸ 7s², so the value should be treated as predicted. | What is darmstadtium used for? → Darmstadtium has no commercial use; it is used only in superheavy element nuclear research and theoretical chemistry. ### Roentgenium (Rg) — https://ferrumone.com/en/element/roentgenium Atom no: 111 | Unknown | Period 7, Group 11 **Title:** Roentgenium: Atomic Number, Uses and Isotopes **Description:** Roentgenium element guide: atomic number 111, symbol Rg, atomic mass 282, source-dependent predicted electron configuration and Rg isotopes. **Keywords:** roentgenium element, roentgenium atomic number, roentgenium electron configuration, roentgenium uses, roentgenium isotopes, roentgenium 282, Wilhelm Roentgen element, Group 11 transactinide, gold analog **Properties:** atomic mass 282 u; electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s¹; state Solid - **History:** Roentgenium was first synthesized at GSI Darmstadt in 1994 by bombarding bismuth-209 with nickel-64 ions. It is named after Wilhelm Conrad Röntgen, discoverer of X-rays and the first Nobel Prize winner in Physics. - **Isotopes:** Roentgenium-282, t½=About 100-130 seconds, Among the longest-lived known roentgenium isotopes; values vary by source and nuclear state. - **Uses:** Nuclear decay-chain research in superheavy elements; Theoretical studies of Group 11 chemistry below gold; Relativistic calculations of d-block superheavy elements - **Biology:** Roentgenium has no biological role. It is synthetic, extremely radioactive and produced only atom by atom. - **Interesting:** Roentgenium’s predicted electron configuration is source-dependent: RSC-style tables commonly list [Rn] 5f¹⁴ 6d¹⁰ 7s¹, while some databases list [Rn] 5f¹⁴ 6d⁹ 7s². No confirmed roentgenium compound has been chemically characterized yet. Its name connects modern superheavy element research with the discovery of X-rays. - **Study notes:** Roentgenium has atomic number 111 and symbol Rg. This data set lists roentgenium as [Rn] 5f¹⁴ 6d¹⁰ 7s¹, but superheavy-element predictions vary by source. Roentgenium is a predicted Group 11 transactinide below gold. Remember Rg-282 for the longest-lived roentgenium isotope range. - **FAQ:** What is the atomic number of roentgenium? → The atomic number of roentgenium is 111. | What is the electron configuration of roentgenium? → This data set lists roentgenium with [Rn] 5f¹⁴ 6d¹⁰ 7s¹; some databases predict [Rn] 5f¹⁴ 6d⁹ 7s², so the value should be treated as predicted. | What is roentgenium used for? → Roentgenium has no commercial use; it is used only in nuclear physics and theoretical chemistry research. ### Copernicium (Cn) — https://ferrumone.com/en/element/copernicium Atom no: 112 | Transition Metal | Period 7, Group 12 **Title:** Copernicium: Atomic Number, Uses and Isotopes **Description:** Copernicium element guide: atomic number 112, symbol Cn, atomic mass 285, predicted electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² and Cn-285. **Keywords:** copernicium element, copernicium atomic number, copernicium electron configuration, copernicium uses, copernicium isotopes, copernicium 285, copernicium chemistry, relativistic noble liquid, copernicium gold surface **Properties:** atomic mass 285 u; electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s²; state Gas - **History:** Copernicium was synthesized at GSI Darmstadt in 1996 by bombarding lead-208 with zinc-70 ions. The element honors Nicolaus Copernicus, whose heliocentric model transformed astronomy. - **Isotopes:** Copernicium-285, t½=About 29 seconds, Longest-lived commonly cited copernicium isotope and useful in atom-at-a-time chemistry discussions. - **Uses:** Gas-phase chemistry experiments on atom-at-a-time superheavy elements; Testing relativistic predictions for Group 12 chemistry; Comparisons with mercury, radon and noble-liquid-like behavior; Nuclear decay studies - **Biology:** Copernicium has no biological role. It is synthetic, radioactive and too short-lived for biological chemistry. - **Interesting:** Copernicium is in Group 12 below mercury, but relativistic effects make it much less metallic than a simple trend would suggest. Gas-phase and surface experiments compare copernicium’s interaction with gold to mercury and radon-like behavior. Theoretical work has described copernicium as a “relativistic noble liquid.” - **Study notes:** Copernicium has atomic number 112 and symbol Cn. Its predicted electron configuration is [Rn] 5f¹⁴ 6d¹⁰ 7s². Copernicium is a Group 12 superheavy element below mercury. Remember Cn for strong relativistic effects and noble-liquid-like behavior. - **FAQ:** What is the atomic number of copernicium? → The atomic number of copernicium is 112. | What is the electron configuration of copernicium? → Copernicium is commonly listed with the predicted electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s². | What is copernicium used for? → Copernicium is used only in superheavy element chemistry and nuclear research. ### Nihonium (Nh) — https://ferrumone.com/en/element/nihonium Atom no: 113 | Post-Transition Metal | Period 7, Group 13 **Title:** Nihonium: Atomic Number, Uses and Isotopes **Description:** Nihonium element guide: atomic number 113, symbol Nh, atomic mass 286, predicted electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p¹ and Nh isotopes. **Keywords:** nihonium element, nihonium atomic number, nihonium electron configuration, nihonium uses, nihonium isotopes, nihonium 286, RIKEN element 113, first element discovered in Asia, Nihon element **Properties:** atomic mass 286 u; electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p¹; state Solid - **History:** Nihonium was first synthesized by the RIKEN team led by Kosuke Morita in 2004 using zinc-70 ions on a bismuth-209 target. IUPAC approved the name in 2016; “Nihon” is a Japanese name for Japan. - **Isotopes:** Nihonium-278, t½=About 2.3 milliseconds, First isotope reported in RIKEN direct synthesis experiments.; Nihonium-286, t½=About 10-20 seconds, Longest-lived commonly cited nihonium isotope; values vary by nuclear data source. - **Uses:** Superheavy nuclear decay-chain research; Testing predicted Group 13 chemistry below thallium; Studies of relativistic inert-pair effects in 7p elements - **Biology:** Nihonium has no biological role. It is synthetic, radioactive and exists only briefly in accelerator experiments. - **Interesting:** Nihonium is the first element discovered in Japan and the first element discovered in Asia. RIKEN produced only a few atoms over years of experiments, showing how rare direct superheavy synthesis events are. The element is predicted to show strong inert-pair effects, making +1 chemistry important relative to +3. - **Study notes:** Nihonium has atomic number 113 and symbol Nh. Its predicted electron configuration is [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p¹. Nihonium is a Group 13 superheavy element below thallium. Remember Nihon means Japan; nihonium is tied to RIKEN and Asian element discovery. - **FAQ:** What is the atomic number of nihonium? → The atomic number of nihonium is 113. | What is the electron configuration of nihonium? → Nihonium is commonly listed with the predicted electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p¹. | What is nihonium used for? → Nihonium has no commercial use; it is used only in superheavy element nuclear research. ### Flerovium (Fl) — https://ferrumone.com/en/element/flerovium Atom no: 114 | Post-Transition Metal | Period 7, Group 14 **Title:** Flerovium: Atomic Number, Uses and Isotopes **Description:** Flerovium element guide: atomic number 114, symbol Fl, atomic mass 289, predicted electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p² and Fl-289. **Keywords:** flerovium element, flerovium atomic number, flerovium electron configuration, flerovium uses, flerovium isotopes, flerovium 289, island of stability, superheavy element 114, Flerov Laboratory **Properties:** atomic mass 289 u; electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p²; state Solid - **History:** Flerovium was synthesized at JINR Dubna in 1999 by bombarding plutonium-244 with calcium-48. It is named after the Flerov Laboratory of Nuclear Reactions and physicist Georgy Flerov. - **Isotopes:** Flerovium-288, t½=About 0.65 seconds, Short-lived isotope used in superheavy decay-chain work.; Flerovium-289, t½=About 2 seconds, Longest-lived commonly cited flerovium isotope; reported values vary slightly by source. - **Uses:** Research on superheavy nuclei near the island of stability; Gas-phase chemistry testing volatile Group 14 behavior; Relativistic chemistry studies comparing flerovium with lead and copernicium - **Biology:** Flerovium has no biological role. It is synthetic, radioactive and produced only in atom-scale quantities. - **Interesting:** Element 114 has long been connected with the predicted island of stability, especially for neutron-rich isotopes not yet reached. Flerovium appears much more volatile than a simple lead-like Group 14 trend would predict. Its chemistry is a key test of how relativistic effects reshape the end of the periodic table. - **Study notes:** Flerovium has atomic number 114 and symbol Fl. Its predicted electron configuration is [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p². Flerovium is Group 14 below lead, but its chemistry may be unusually volatile. Remember Fl for island of stability discussions around Z = 114. - **FAQ:** What is the atomic number of flerovium? → The atomic number of flerovium is 114. | What is the electron configuration of flerovium? → Flerovium is commonly listed with the predicted electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p². | What is flerovium used for? → Flerovium is used only in superheavy element nuclear and theoretical chemistry research. ### Moscovium (Mc) — https://ferrumone.com/en/element/moscovium Atom no: 115 | Post-Transition Metal | Period 7, Group 15 **Title:** Moscovium: Atomic Number, Uses and Isotopes **Description:** Moscovium element guide: atomic number 115, symbol Mc, atomic mass 290, predicted electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p³ and Mc isotopes. **Keywords:** moscovium element, moscovium atomic number, moscovium electron configuration, moscovium uses, moscovium isotopes, moscovium 290, moscovium decay chain, element 115, Moscow Oblast element **Properties:** atomic mass 290 u; electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p³; state Solid - **History:** Moscovium was synthesized in 2003 by JINR Dubna with US collaborators using americium-243 targets and calcium-48 ions. The name honors Moscow Oblast, where JINR is located. - **Isotopes:** Moscovium-289, t½=About 0.22-0.41 seconds, Short-lived isotope that decays by alpha emission toward nihonium; values vary by source.; Moscovium-290, t½=About 0.65-0.84 seconds, Longest-lived commonly cited moscovium isotope; decays toward nihonium-286. - **Uses:** Superheavy nuclear decay-chain research; Parent-decay routes that help identify nihonium isotopes; Theoretical Group 15 chemistry below bismuth; Relativistic inert-pair effect studies - **Biology:** Moscovium has no biological role. It is synthetic, radioactive and exists for fractions of a second. - **Interesting:** Moscovium decay chains helped independent teams connect element 115 work with nihonium nuclei. Its chemistry has not been experimentally characterized, but calculations compare it with bismuth. The element name recognizes the Moscow region, a major center of superheavy element research. - **Study notes:** Moscovium has atomic number 115 and symbol Mc. Its predicted electron configuration is [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p³. Moscovium is a Group 15 superheavy element below bismuth. Remember Mc-290 for decay chains leading to nihonium-286. - **FAQ:** What is the atomic number of moscovium? → The atomic number of moscovium is 115. | What is the electron configuration of moscovium? → Moscovium is commonly listed with the predicted electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p³. | What is moscovium used for? → Moscovium has no commercial use; it is used only in superheavy element nuclear research. ### Livermorium (Lv) — https://ferrumone.com/en/element/livermorium Atom no: 116 | Post-Transition Metal | Period 7, Group 16 **Title:** Livermorium: Atomic Number, Uses and Isotopes **Description:** Livermorium element guide: atomic number 116, symbol Lv, atomic mass 293, predicted electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁴ and Lv-293. **Keywords:** livermorium element, livermorium atomic number, livermorium electron configuration, livermorium uses, livermorium isotopes, livermorium 293, Lawrence Livermore element, Group 16 superheavy element **Properties:** atomic mass 293 u; electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁴; state Solid - **History:** Livermorium was synthesized in 2000 by JINR Dubna and Lawrence Livermore National Laboratory using curium-248 targets and calcium-48 ions. IUPAC approved the name in 2012. - **Isotopes:** Livermorium-292, t½=About 0.6-16 milliseconds, Short-lived livermorium isotope; reported values vary by experiment and nuclear data source.; Livermorium-293, t½=About 53-80 milliseconds, Longest-lived commonly cited livermorium isotope; reported values vary by source. - **Uses:** Superheavy nuclear decay-chain research; Theoretical Group 16 chemistry below polonium; Relativistic calculations for 7p-block elements - **Biology:** Livermorium has no biological role. It is synthetic, highly radioactive and survives only for milliseconds. - **Interesting:** Livermorium honors the Livermore laboratory, which contributed target material and superheavy element expertise. Its predicted chemistry is related to polonium but may be strongly altered by relativistic effects. Livermorium is part of the 7p superheavy block that completed period 7 of the periodic table. - **Study notes:** Livermorium has atomic number 116 and symbol Lv. Its predicted electron configuration is [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁴. Livermorium is a Group 16 superheavy element below polonium. Remember Lv-293 for a millisecond half-life range. - **FAQ:** What is the atomic number of livermorium? → The atomic number of livermorium is 116. | What is the electron configuration of livermorium? → Livermorium is commonly listed with the predicted electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁴. | What is livermorium used for? → Livermorium is used only in superheavy nuclear research and theoretical chemistry. ### Tennessine (Ts) — https://ferrumone.com/en/element/tennessine Atom no: 117 | Halogen | Period 7, Group 17 **Title:** Tennessine: Atomic Number, Uses and Isotopes **Description:** Tennessine element guide: atomic number 117, symbol Ts, atomic mass 294, predicted electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁵ and Ts-294. **Keywords:** tennessine element, tennessine atomic number, tennessine electron configuration, tennessine uses, tennessine isotopes, tennessine 294, berkelium 249 target, superheavy halogen, Tennessee element **Properties:** atomic mass 294 u; electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁵; state Solid - **History:** Tennessine was synthesized in 2010 by a collaboration involving JINR Dubna, Oak Ridge National Laboratory, Lawrence Livermore, Vanderbilt and other partners. Oak Ridge supplied the rare berkelium-249 target; IUPAC approved the name in 2016. - **Isotopes:** Tennessine-293, t½=About 22-25 milliseconds, Short-lived isotope produced in the berkelium-calcium synthesis route.; Tennessine-294, t½=About 50-80 milliseconds, Longest-lived known tennessine isotope and parent of moscovium-290 in alpha decay. - **Uses:** Superheavy nuclear research near the end of period 7; Testing predicted halogen behavior below astatine; Studies of berkelium-249 target production and international element synthesis; Relativistic chemistry calculations for Group 17 - **Biology:** Tennessine has no biological role. It is synthetic, radioactive and exists only for milliseconds. - **Interesting:** Tennessine is placed in the halogen group, but calculations suggest it may not form a stable -1 anion as readily as lighter halogens. The berkelium-249 target had to be produced and transported within a narrow time window because it is radioactive. Tennessine’s name honors Tennessee, home to Oak Ridge and Vanderbilt contributions to the discovery. - **Study notes:** Tennessine has atomic number 117 and symbol Ts. Its predicted electron configuration is [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁵. Tennessine is the heaviest halogen, below astatine. Remember Ts-294 and the Bk-249 + Ca-48 synthesis route. - **FAQ:** What is the atomic number of tennessine? → The atomic number of tennessine is 117. | What is the electron configuration of tennessine? → Tennessine is commonly listed with the predicted electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁵. | What is tennessine used for? → Tennessine has no commercial use; it is used only in superheavy element nuclear research. ### Oganesson (Og) — https://ferrumone.com/en/element/oganesson Atom no: 118 | Noble Gas | Period 7, Group 18 **Title:** Oganesson: Atomic Number, Uses and Isotopes **Description:** Oganesson element guide: atomic number 118, symbol Og, atomic mass 294, predicted electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁶ and Og-294. **Keywords:** oganesson element, oganesson atomic number, oganesson electron configuration, oganesson uses, oganesson isotopes, oganesson 294, heaviest known element, element 118, Yuri Oganessian, period 7 complete **Properties:** atomic mass 294 u; electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁶; state Solid - **History:** Oganesson was first synthesized in 2002 by JINR Dubna and Lawrence Livermore using californium targets and calcium-48 ions. IUPAC approved the name in 2016 to honor Yuri Oganessian, a pioneer of superheavy element research. - **Isotopes:** Oganesson-294, t½=About 0.7-0.9 milliseconds, Only confirmed oganesson isotope in common references; decays by alpha emission toward livermorium. - **Uses:** Research on the heaviest known nuclei; Theoretical chemistry of the end of period 7; Relativistic studies of noble-gas-group behavior; Guidance for searches beyond element 118 - **Biology:** Oganesson has no biological role. Only a few atoms have been produced, and oganesson-294 decays in roughly millisecond or sub-millisecond time scales. - **Interesting:** Oganesson completes the seventh period of the periodic table. Although it sits in Group 18, calculations suggest oganesson may be far more reactive and less noble-gas-like than radon. Oganesson is one of the few elements named after a living scientist at the time of naming. Elements 119 and beyond have not yet been confirmed, so oganesson remains the end of the officially named periodic table. - **Study notes:** Oganesson has atomic number 118 and symbol Og. Its predicted electron configuration is [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁶. Oganesson is in Group 18, but relativistic effects may make it chemically unusual. Remember Og-294, Yuri Oganessian and completion of period 7. - **FAQ:** What is the atomic number of oganesson? → The atomic number of oganesson is 118. | What is the electron configuration of oganesson? → Oganesson has the predicted electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁶. | What is oganesson used for? → Oganesson has no commercial use; it is used only in superheavy element nuclear and theoretical chemistry research. --- ## Turkish Blog Posts (30 published) **Index:** https://ferrumone.com/blog | **RSS:** https://ferrumone.com/blog/feed.xml All posts are Turkish YKS chemistry guides. Public, indexable, no login required. - [Laboratuvar Malzemeleri ve Güvenlik İşaretleri: Tam Liste ve Kullanım Alanları](https://ferrumone.com/blog/laboratuvar-malzemeleri-ve-guvenlik-isaretleri-tam-liste-kullanim-alanlari): Laboratuvar malzemeleri ve güvenlik işaretlerini tam liste, kullanım alanları, TYT kimya ipuçları ve uyarı sembolleriyle öğren, güvenli çalış ve pekiştir. (Turkish; Article + FAQPage JSON-LD) - [Maddenin Halleri: Katı, Sıvı, Gaz, Buhar Basıncı ve Hal Değişim Grafikleri](https://ferrumone.com/blog/maddenin-halleri-kati-sivi-gaz-buhar-basinci-hal-degisim-grafikleri): Maddenin halleri, katı-sıvı-gaz özellikleri, buhar basıncı, kaynama ve hal değişim grafiklerini TYT kimya düzeyinde tablolar ve çözümlü örneklerle öğren. (Turkish; Article + FAQPage JSON-LD) - [Kimyasal Türler Arası Etkileşimler: Güçlü-Zayıf Etkileşimler, Polar-Apolar ve Hidrojen Bağı](https://ferrumone.com/blog/kimyasal-turler-arasi-etkilesimler-guclu-zayif-polar-apolar-etkilesimler-hidrojen-bagi): Kimyasal türler arası etkileşimlerde güçlü-zayıf etkileşimler, polar-apolar ayrımı, hidrojen bağı ve van der Waals örneklerini YKS düzeyinde öğren ve pekiştir. (Turkish; Article + FAQPage JSON-LD) - [Çözünürlük Çarpımı: Kçç (Ksp), Çökelme ve Ortak İyon Etkisi](https://ferrumone.com/blog/cozunurluk-carpimi-kcc-ksp-cokelme-ortak-iyon-etkisi): Çözünürlük çarpımı Kçç (Ksp), çökelme koşulu, Qçç-Kçç karşılaştırması ve ortak iyon etkisini AYT kimya düzeyinde çözümlü örneklerle öğren ve pekiştir. (Turkish; Article + FAQPage JSON-LD) - [AYT Kimya Formülleri ve Önemli Tepkimeler: Sınav Öncesi Tekrar Listesi](https://ferrumone.com/blog/ayt-kimya-formulleri-ve-onemli-tepkimeler-sinav-oncesi-tekrar-listesi): AYT Kimya formülleri ve önemli tepkimeler: denge, hız, termokimya, elektrokimya ve organik kimyayı sınav öncesi tekrar listesiyle toparla ve netini artır. (Turkish; Article + FAQPage JSON-LD) - [Atom Modelleri: Dalton, Thomson, Rutherford, Bohr ve Modern Atom Modeli](https://ferrumone.com/blog/atom-modelleri-dalton-thomson-rutherford-bohr-modern-atom-modeli): Atom modelleri: Dalton, Thomson, Rutherford, Bohr ve modern atom modelini karşılaştırmalı tablo, sınav notları ve kısa özetle öğren, farkları ayırt et. 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(Turkish; Article + FAQPage JSON-LD) - [TYT Kimya Formülleri ve Kısa Notlar: Sınav Öncesi Hızlı Tekrar Rehberi](https://ferrumone.com/blog/tyt-kimya-formulleri-kisa-notlar-sinav-oncesi-hizli-tekrar-rehberi): TYT Kimya formülleri ve kısa notlar: mol, derişim, pH yorumu, gaz hacmi ve sınav öncesi hızlı tekrar tablolarını örneklerle öğren ve netini artır hemen. (Turkish; Article + FAQPage JSON-LD) - [YKS Kimya Son 30 Gün Çalışma Programı: TYT ve AYT İçin Hızlı Tekrar Planı](https://ferrumone.com/blog/yks-kimya-son-30-gun-calisma-programi-tyt-ayt-hizli-tekrar-plani): YKS Kimya son 30 gün çalışma programı: TYT ve AYT kimya için hızlı tekrar planı, deneme analizi, çıkmış soru ve konu önceliklerini gün gün uygula ve tamamla. (Turkish; Article + FAQPage JSON-LD) - [Lewis Yapıları Nasıl Çizilir? Molekül Çizimi, Rezonans ve Formal Yük](https://ferrumone.com/blog/lewis-yapilari-nasil-cizilir-molekul-cizimi-rezonans-formal-yuk): Lewis yapıları nasıl çizilir? Molekül çizimi, rezonans, formal yük, oktet-duet kuralı ve çözümlü YKS kimya örnekleriyle adım adım öğren ve pratik yap. (Turkish; Article + FAQPage JSON-LD) - [Kimyasal Tepkimelerde Denge: Kc, Kp ve Le Châtelier Prensibi](https://ferrumone.com/blog/kimyasal-tepkimelerde-denge-kc-kp-le-chatelier-prensibi): Kimyasal denge konusunu Kc, Kp, Q karşılaştırması ve Le Châtelier prensibiyle öğren; AYT kimya için çözümlü örneklerle adım adım pratik yap ve net artır. (Turkish; Article + FAQPage JSON-LD) - [Kimyasal Tepkimelerde Enerji ve Termokimya: Entalpi, Hess Yasası, Bağ Enerjisi](https://ferrumone.com/blog/kimyasal-tepkimelerde-enerji-ve-termokimya-entalpi-hess-yasasi-bag-enerjisi): Termokimya, entalpi, Hess yasası ve bağ enerjisi hesaplarını AYT kimya düzeyinde öğren; formüller, tablolar ve çözümlü örneklerle net artırmaya başla. (Turkish; Article + FAQPage JSON-LD) - [Kimyasal Tepkimelerde Hız: Hız Denklemi ve Grafik Yorumlama](https://ferrumone.com/blog/kimyasal-tepkimelerde-hiz): Kimyasal tepkimelerde hız, hız denklemi, tepkime derecesi, aktivasyon enerjisi, katalizör ve grafik yorumlamayı AYT kimya için çözümlü örneklerle öğren. (Turkish; Article + FAQPage JSON-LD) - [AYT Kimya ve Elektrik: Elektrokimya, Pil ve Elektroliz Konu Özeti](https://ferrumone.com/blog/ayt-kimya-ve-elektrik-elektrokimya-pil-ve-elektroliz): AYT Kimya ve Elektrik konusunu elektrokimya, galvanik pil, elektroliz, elektrot potansiyeli ve Faraday hesaplarıyla çözümlü örneklerle öğren ve pekiştir. (Turkish; Article + FAQPage JSON-LD) - [Kimyasal Denklem Denkleştirme: Adım Adım Yöntemler ve Püf Noktaları](https://ferrumone.com/blog/kimyasal-denklem-denklestirme): Kimyasal denklem denkleştirme nasıl yapılır? Katsayı bulma, redoks ve yarı tepkime yöntemlerini YKS düzeyinde çözümlü örneklerle öğren ve pekiştir hemen. (Turkish; Article + FAQPage JSON-LD) - [Modern Atom Teorisi: Kuantum Sayıları, Orbital ve Elektron Dizilimi](https://ferrumone.com/blog/modern-atom-teorisi-kuantum-sayilari-orbital-elektron-dizilimi): Modern atom teorisi; kuantum sayıları, orbital türleri, elektron dizilimi, Aufbau-Hund-Pauli kuralları ve çözümlü AYT kimya örnekleriyle adım adım öğren. (Turkish; Article + FAQPage JSON-LD) - [Kimyasal Bağlar: İyonik, Kovalent, Metalik Bağ ve Lewis Yapıları](https://ferrumone.com/blog/kimyasal-baglar-iyonik-kovalent-metalik-bag-lewis-yapilari): Kimyasal bağlar; iyonik, kovalent, metalik bağ türleri, polar-apolar ayrımı ve Lewis yapısı çizimini TYT AYT kimya için adım adım örneklerle öğren ve pekiştir. (Turkish; Article + FAQPage JSON-LD) - [AYT Organik Kimya: Fonksiyonel Gruplar, Adlandırma ve Soru Çözme Mantığı](https://ferrumone.com/blog/ayt-organik-kimya-fonksiyonel-gruplar-adlandirma): AYT organik kimyada fonksiyonel gruplar, IUPAC adlandırma, izomerlik ve soru çözme mantığını tablo, adım adım yöntem ve çözümlü örneklerle detaylı öğren. (Turkish; Article + FAQPage JSON-LD) - [Hidrokarbonlar ve İzomerlik: Alkan, Alken, Alkin ve İzomer Türleri](https://ferrumone.com/blog/hidrokarbonlar-ve-izomerlik-alkan-alken-alkin-ve-izomer-turleri): Hidrokarbonlar ve izomerlik konusunu alkan, alken, alkin, genel formüller, adlandırma, cis-trans izomerliği, sık hatalar ve çözümlü AYT örnekleriyle öğren. (Turkish; Article + FAQPage JSON-LD) - [Sıvı Çözeltiler ve Derişim: Molarite, Seyreltme ve Karışım Problemleri](https://ferrumone.com/blog/sivi-cozeltiler-ve-derisim-molarite-seyreltme-ve-karisim-problemleri): Sıvı çözeltiler ve derişim konusunu molarite, seyreltme formülü, karışım problemleri, yüzde derişim ve çözümlü AYT örnekleriyle pratik öğren ve net çöz. (Turkish; Article + FAQPage JSON-LD) - [pH Hesaplama Nasıl Yapılır? Asit, Baz, Tampon ve Titrasyon Soruları](https://ferrumone.com/blog/ph-hesaplama-nasil-yapilir): pH hesaplama nasıl yapılır? Asit, baz, tampon ve titrasyon sorularında pH-pOH formüllerini YKS düzeyinde çözümlü örneklerle öğren ve pratik yapabilirsin. (Turkish; Article + FAQPage JSON-LD) - [Gazlar: İdeal Gaz Denklemi, Gaz Karışımları ve Hızlı Çözüm Taktikleri](https://ferrumone.com/blog/gazlar-ideal-gaz-denklemi-gaz-karisimlari): Gazlar konusu için PV=nRT, gaz karışımları, kısmi basınç ve hızlı çözüm taktiklerini AYT kimya düzeyinde örneklerle öğren ve soruları daha hızlı çöz şimdi. (Turkish; Article + FAQPage JSON-LD) - [Periyodik Tablo ve Elementlerin Özellikleri](https://ferrumone.com/blog/periyodik-tablo-elementlerin-ozellikleri): Periyodik tablo nasıl okunur? Grup, periyot, metal-ametal-yarı metal ayrımı ve elementlerin özelliklerini YKS düzeyinde örneklerle öğren ve pekiştir hemen. (Turkish; Article + FAQPage JSON-LD) - [2026 YKS TYT Kimya Konuları ve Son Yılların Soru Dağılımı](https://ferrumone.com/blog/2026-tyt-kimya-konulari-soru-dagilimi): 2026 TYT sınavında kimyadan 7 soru geliyor. Hangi üniteden kaç soru çıktığını, 2018–2025 soru dağılım tablosunu ve çalışma önceliklerini bu rehberde bul. (Turkish; Article + FAQPage JSON-LD) - [2026 YKS AYT Kimya Konuları ve Soru Dağılımı: Hangi Üniteden Kaç Soru Gelir?](https://ferrumone.com/blog/2026-ayt-kimya-konulari-soru-dagilimi): 2026 AYT Kimya konuları ve 2018-2025 soru dağılımı: 13 kimya sorusunda hangi üniteden kaç soru geldiğini ve çalışma önceliklerini gör. Güncel tabloyla plan yap. (Turkish; Article + FAQPage JSON-LD) - [AYT Kimyada En Çok Çıkan Konular: Net Artırmak İçin Öncelik Sıralaması](https://ferrumone.com/blog/ayt-kimyada-en-cok-cikan-konular): 2018-2025 AYT Kimya dağılımına göre en çok çıkan konuları, net artıran öncelik sırasını ve çalışma planını gör. Organik ve elektrokimya neden öne çıkıyor? (Turkish; Article + FAQPage JSON-LD) - [YKS Kimya Çıkmış Sorular Analizi: Son 5 Yıla Göre En Çok Çıkan Konular](https://ferrumone.com/blog/yks-kimya-cikmis-sorular-analizi): YKS Kimya çıkmış sorular analizi: 2021-2025 TYT ve AYT kimyada en çok çıkan konuları, son 5 yıl tablolarını ve net artıran çalışma önceliklerini incele. (Turkish; Article + FAQPage JSON-LD) - [AYT Kimya Nasıl Çalışılır? Haftalık Plan ve Net Artırma Stratejisi](https://ferrumone.com/blog/ayt-kimya-nasil-calisilir): AYT Kimya nasıl çalışılır? 8 haftalık çalışma planı, konu önceliği, deneme analizi ve net artırma stratejisini 2026 YKS için örnek programla öğren şimdi. (Turkish; Article + FAQPage JSON-LD) - [Mol Hesaplama Nasıl Yapılır? Mol-Kütle-Tane-Hacim Dönüşümleri](https://ferrumone.com/blog/mol-hesaplama-nasil-yapilir): Mol hesaplama nasıl yapılır? Mol-kütle, mol-tane ve mol-hacim dönüşümlerini YKS düzeyinde formüller, örnekler ve Ferrum Mol Hesaplayıcı ile öğren şimdi. (Turkish; Article + FAQPage JSON-LD) --- ## Turkish Document Guides (24 pages) **Index:** https://ferrumone.com/panel/dokumanlar Each document has a public SEO guide page (topic breakdown, FAQ, HowTo). PDF file requires free login in Ferrum Panel. AI bots may retrieve guide text without authentication. - [AYT Modern Atom Teorisi Full Tekrar Denemesi Cevap Anahtarı PDF ve Rehberi](https://ferrumone.com/panel/dokumanlar/modern-atom-teorisi): Ferrum AYT Modern Atom Teorisi ünite denemesi cevap anahtarı: 6 sayfa, 10 madde (A–E). Soru metni yok; MEB 11.1 kazanımları. Ferrum rehberi ücretsiz; PDF girişle panelde görüntülenir. - [AYT Gazlar Full Tekrar Denemesi Cevap Anahtarı PDF ve Rehberi](https://ferrumone.com/panel/dokumanlar/gazlar): Ferrum AYT Gazlar ünite denemesi cevap anahtarı: 7 sayfa, 12 madde (A–E). Soru metni yok; ideal gaz ve kinetik teori. Ferrum rehberi ücretsiz; PDF girişle panelde görüntülenir. - [AYT Sıvı Çözeltiler ve Çözünürlük Full Tekrar Denemesi Cevap Anahtarı PDF ve Rehberi](https://ferrumone.com/panel/dokumanlar/cozeltiler): Ferrum AYT Sıvı Çözeltiler ünite denemesi cevap anahtarı: 7 sayfa, 12 madde (A–E). Soru metni yok; molarite, çözünürlük. Ferrum rehberi ücretsiz; PDF girişle panelde görüntülenir. - [AYT Kimyasal Tepkimelerde Enerji Full Tekrar Denemesi Cevap Anahtarı PDF ve Rehberi](https://ferrumone.com/panel/dokumanlar/enerji): Ferrum AYT Enerji ünite denemesi cevap anahtarı: 5 sayfa, 8 madde (A–E). Soru metni yok; Hess ve bağ enerjisi. Ferrum rehberi ücretsiz; PDF girişle panelde görüntülenir. - [AYT Kimyasal Tepkimelerde Hız Full Tekrar Denemesi Cevap Anahtarı PDF ve Rehberi](https://ferrumone.com/panel/dokumanlar/hiz): Ferrum AYT Hız ünite denemesi cevap anahtarı: 4 sayfa, 6 madde (A–E). Soru metni yok; hız yasası ve katalizör. Ferrum rehberi ücretsiz; PDF girişle panelde görüntülenir. - [AYT Kimyasal Tepkimelerde Denge Full Tekrar Denemesi Cevap Anahtarı PDF ve Rehberi](https://ferrumone.com/panel/dokumanlar/denge): Ferrum AYT Denge ünite denemesi cevap anahtarı: 12 sayfa, 22 madde (A–E). Soru metni yok; asit-baz ve çözünürlük dahil. Ferrum rehberi ücretsiz; PDF girişle panelde görüntülenir. - [AYT Kimyasal Denge Konu Denemeleri PDF ve Rehberi](https://ferrumone.com/panel/dokumanlar/kimyasal-denge-konu-denemeleri): Ferrum kimyasal denge konu denemesi: 6 sayfa, 5 soru (Kc, Kp, Le Chatelier). Cevaplar 1-A, 2-D, 3-D, 4-A, 5-D. Rehber ücretsiz; PDF girişle panelde. - [AYT Kimya ve Elektrik (Elektrokimya) Full Tekrar Denemesi Cevap Anahtarı PDF ve Rehberi](https://ferrumone.com/panel/dokumanlar/elektrokimya): Ferrum AYT Elektrokimya ünite denemesi cevap anahtarı: 9 sayfa, 16 madde (A–E). Soru metni yok; galvanik pil, Faraday. Ferrum rehberi ücretsiz; PDF girişle panelde görüntülenir. - [AYT Karbon Kimyasına Giriş Full Tekrar Denemesi Cevap Anahtarı PDF ve Rehberi](https://ferrumone.com/panel/dokumanlar/karbon-kimyasina-giris): Ferrum AYT Karbon Kimyasına Giriş cevap anahtarı: 7 sayfa, 12 madde (A–E). Soru metni yok; hibritleşme, VSEPR. Ferrum rehberi ücretsiz; PDF girişle panelde görüntülenir. - [AYT Organik Bileşikler Full Tekrar Denemesi Cevap Anahtarı PDF ve Rehberi](https://ferrumone.com/panel/dokumanlar/organik-bilesikler): Ferrum AYT Organik Bileşikler cevap anahtarı: 13 sayfa, 24 madde (A–E). Soru metni yok; IUPAC, alkan–ester. Ferrum rehberi ücretsiz; PDF girişle panelde görüntülenir. - [AYT Organik Kimya 1 Konu Denemeleri Full Tekrar Cevap Anahtarı PDF ve Rehberi](https://ferrumone.com/panel/dokumanlar/organik-kimya-1-konu-denemeleri): Ferrum Organik Kimya 1 konu denemesi cevap anahtarı: 6 sayfa, 5 madde (A–E). Soru metni yok; kısa konu denemesi formatı. Ferrum rehberi ücretsiz; PDF girişle panelde görüntülenir. - [AYT Asit-Baz Dengesi ve Kç Konu Denemeleri PDF ve Rehberi](https://ferrumone.com/panel/dokumanlar/asit-baz-dengesi-ve-kcc-konu-denemeleri): Ferrum asit-baz dengesi ve Kç konu denemesi: 6 sayfa, 5 soru (HCl–NaOH pH, HCl–KOH titrasyon grafiği, tampon, Kç). Cevaplar 1-A, 2-A, 3-D, 4-A, 5-D. Rehber ücretsiz; PDF girişle panelde. - [AYT Elektroliz Konu Denemeleri PDF ve Rehberi](https://ferrumone.com/panel/dokumanlar/elektroliz-konu-denemeleri): Ferrum elektroliz konu denemesi: 6 sayfa, 5 soru (elektrolitik hücre, Faraday, verim). Rehber ücretsiz; PDF girişle panelde. - [9. Sınıf Kimya 2. Dönem 2. Yazılı Soruları PDF ve Konu Rehberi](https://ferrumone.com/panel/dokumanlar/sinif-9-2-donem-2-yazili): Orbital Yayınları 9. sınıf 2. dönem 2. ortak yazılı: 10 sayfa, 9 soru, çözümlü ve cevap anahtarlı PDF. Lewis, IUPAC, etkileşimler. Ferrum konu rehberi ücretsiz; PDF girişle panelde görüntülenir. - [10. Sınıf Kimya 2. Dönem 2. Yazılı Soruları PDF ve Konu Rehberi](https://ferrumone.com/panel/dokumanlar/sinif-10-2-donem-2-yazili): Orbital 10. sınıf 2. dönem 2. ortak yazılı: 8 sayfa, 6 soru, çözümlü PDF. Gaz difüzyonu, molarite, çözünürlük. Ferrum konu rehberi ücretsiz; PDF girişle panelde görüntülenir. - [11. Sınıf Kimya 2. Dönem 2. Yazılı Soruları PDF ve AYT Hazırlık Rehberi](https://ferrumone.com/panel/dokumanlar/sinif-11-2-donem-2-yazili): Orbital 11. sınıf 2. dönem 2. yazılı: 8 sayfa, 8 soru, çözümlü PDF. Hess, hız, denge, pH — AYT hazırlık. Ferrum konu rehberi ücretsiz; PDF girişle panelde görüntülenir. - [12. Sınıf Kimya 2. Dönem 1. Yazılı Soruları PDF ve Organik Kimya Rehberi](https://ferrumone.com/panel/dokumanlar/sinif-12-2-donem-2-yazili): Orbital 2025/2026 12. sınıf 2. dönem 1. yazılı: 5 sayfa, 6 soru, çözümlü PDF. VSEPR, IUPAC, AYT organik. Ferrum konu rehberi ücretsiz; PDF girişle panelde görüntülenir. - [46 Soruda AYT Kimya Full Tekrar Cevap Anahtarı PDF ve Rehberi](https://ferrumone.com/panel/dokumanlar/46-soruda-ayt-full-tekrar): Ferrum 46 soruda AYT kimya full tekrar cevap anahtarı PDF: 46 sayfa, 46 madde (A–E). Soru metni yok; ünite eşleştirmeli anahtar. Ferrum konu rehberi ücretsiz; PDF girişle panelde görüntülenir. - [46 Soruda TYT Kimya Full Tekrar PDF ve Rehberi](https://ferrumone.com/panel/dokumanlar/46-soruda-tyt-full-tekrar): Ferrum 46 soruda TYT kimya full tekrar PDF: 48 sayfa, 46 soru (A–E). Kimya bilimi, atom, etkileşimler, maddenin halleri, hesaplamalar, karışımlar, asit-baz. Rehber ücretsiz; PDF girişle panelde. - [TYT Kimya Son 8 Yıl Konu Konu Çıkmış Sorular PDF ve Çalışma Rehberi](https://ferrumone.com/panel/dokumanlar/tyt-son-8-yil-cikmislar): Alan Yayınları TYT–MSÜ son 8 yıl çıkmış: 23 sayfa, 108 soru (2018–2025), çözümlü cevap anahtarlı PDF. 8 ünite konu konu. Ferrum rehberi ücretsiz; PDF girişle panelde görüntülenir. - [AYT Kimya Son 8 Yıl Konu Konu Çıkmış Sorular PDF ve Çalışma Rehberi](https://ferrumone.com/panel/dokumanlar/ayt-son-8-yil-cikmislar): Alan Yayınları AYT son 8 yıl çıkmış: 27 sayfa, 99 soru (2018–2025), çözümlü cevap anahtarlı PDF. Denge, elektrokimya, organik. Ferrum rehberi ücretsiz; PDF girişle panelde görüntülenir. - [Orbital Organik Kimya Özet PDF ve AYT Organik Konu Rehberi](https://ferrumone.com/panel/dokumanlar/orbital-organik-kimya-ozet): Orbital AYT organik kimya özet: 46 sayfa konu anlatımlı PDF (sınav sorusu değil). YKS organik, AYT 8–9. ünite. Ferrum rehberi ücretsiz; PDF girişle panelde görüntülenir. - [Orbital Organik Adlandırma PDF ve IUPAC Çalışma Rehberi](https://ferrumone.com/panel/dokumanlar/orbital-organik-adlandirma): Orbital organik adlandırma: 16 sayfa, 8 test, 120 hidrokarbon IUPAC alıştırması. YKS organik, AYT 9. ünite. Ferrum rehberi ücretsiz; PDF girişle panelde görüntülenir. - [Organik Bileşiklerin Adlandırılması Uygulama PDF ve Çözüm Rehberi](https://ferrumone.com/panel/dokumanlar/organik-bilesikler-adlandirma-uygulama): Orbital hidrokarbon uygulama: 18 sayfa, 8 UYGULAMA, 96 soru, cevap anahtarlı çözümlü PDF. YKS organik adlandırma. Ferrum rehberi ücretsiz; PDF girişle panelde görüntülenir. --- ## Turkish Book Detail Pages (6 books) **Catalog:** https://ferrumone.com/kitaplar Public SEO detail pages for Ferrum Yayıncılık TYT/AYT chemistry books. Free PDF via login at https://ferrumone.com/panel/kitap-pdfleri. - [TYT Kimya Ferrum Video Ders Kitabı](https://ferrumone.com/kitaplar/tyt-kimya-video-ders-kitabi): TYT Kimya Ferrum Video Ders Kitabı: 224 sayfa, 9 ünite, Simetrik Deneme + YouGİS + Soru Kampı. Ferrum videoları ve 22 günlük TYT kampıyla eşleşir. PDF ücretsiz. 279 TL — kitapdoldur.com. (Turkish; Book + Product + LearningResource + HowTo + FAQPage JSON-LD) - [AYT Kimya Ferrum 21 × 13 Branş Denemeleri](https://ferrumone.com/kitaplar/ayt-kimya-brans-denemeleri): AYT Kimya Ferrum 21×13 Branş Denemeleri: 160 sayfa, 3 fasikül, 273 soru. Orta → ÖSYM → Ferrum Team zorluk. Düğüm düzlemi, indikatör, derişim pili dahil. Çözüm videoları. 249 TL. (Turkish; Book + Product + LearningResource + HowTo + FAQPage JSON-LD) - [TYT Kimya Ferrum 30 × 7 Branş Denemeleri](https://ferrumone.com/kitaplar/tyt-kimya-brans-denemeleri): TYT Kimya Ferrum 30×7 Branş Denemeleri: 160 sayfa, 5 fasikül, 210 soru (30 deneme × 7). Infografik konu tekrarı + kademeli denemeler. Çözüm videoları ücretsiz. 249 TL. (Turkish; Book + Product + LearningResource + HowTo + FAQPage JSON-LD) - [TYT Kimya Ferrum Tekrar Soru Kampı](https://ferrumone.com/kitaplar/tyt-kimya-tekrar-soru-kampi): TYT Kimya Ferrum Tekrar Soru Kampı: 160 sayfa, 10 fasikül, ~630 soru. Sarmal tekrar; her kazanımdan en az 1 soru. Deneme öncesi 1 saatte TYT tekrarı. Çözüm videoları. 249 TL. (Turkish; Book + Product + LearningResource + HowTo + FAQPage JSON-LD) - [AYT Kimya Ferrum Tekrar Soru Kampı](https://ferrumone.com/kitaplar/ayt-kimya-tekrar-soru-kampi): AYT Kimya Ferrum Tekrar Soru Kampı: 160 sayfa, 10 fasikül, ~630 soru. Sarmal tekrar; organik, elektrokimya, denge dahil. Deneme öncesi 1 saatte AYT tekrarı. Çözüm videoları. 249 TL. (Turkish; Book + Product + LearningResource + HowTo + FAQPage JSON-LD) - [Ferrum AYT Kimya Video Ders Kitabı](https://ferrumone.com/kitaplar/ayt-kimya-video-ders-kitabi): Ferrum AYT Kimya VDK: 336 sayfa, ~900 soru, 11 ünite, Simetrik Deneme + 13 soruluk YouGİS. 46 günlük AYT kampıyla eşleşir. Doç. Dr. Hamdi Özkan, Prof. Dr. Serkan Yavuz. PDF ücretsiz. 379 TL. 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