Ra
226.000Radium
Radyum
Radium is a radioactive alkaline earth metal with atomic number 88. It is known for Marie Curie’s work, radium-226, radon production, historical luminous paint, the Radium Girls and radium-223 bone-metastasis therapy.
88
226 g/mol
[Rn] 7s²
2 | 8 | 18 | 32 | 18 | 8 | 2
0.9
5.5 g/cm³
959.9 °C
1736.8 °C
Marie & Pierre Curie
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.
Radium-223
Half-life: About 11.4 days. Alpha-emitting isotope used as radium-223 dichloride in nuclear medicine.Radium-226
Half-life: About 1600 years. Important natural radium isotope and parent of radon-222.Radium-228
Half-life: About 5.75 years. Thorium-series beta-emitting radium isotope.RaCl₂
Radium ChlorideHistorical radium compound and formulation context for radium-223 dichloride.RaBr₂
Radium BromideEarly radium research compound.RaSO₄
Radium SulfateVery insoluble radium compound relevant to environmental chemistry.- 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
Radium has no biological role. Chemically it resembles calcium and can deposit in bone, where radioactive decay can damage tissue.
- 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.
- 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.
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.
What is radium-223 used for?
Radium-223 dichloride is used for certain prostate cancers with symptomatic bone metastases and no known visceral metastatic disease.
What is radium-226?
Radium-226 is a long-lived alpha-emitting isotope with a half-life of about 1600 years and is a parent of radon-222.
Who were the Radium Girls?
The Radium Girls were workers harmed by painting watch dials with radium-containing luminous paint, a case that became important in occupational safety history.