Lr
262.000Lawrencium
Lavrensiyum
Lawrencium is the last actinide, with atomic number 103. It is known for its unusual 7p¹ electron configuration, lawrencium ionization energy measurements, short-lived isotopes and the end of the actinide series.
103
262 g/mol
[Rn] 5f¹⁴ 7s² 7p¹
2 | 8 | 18 | 32 | 32 | 8 | 3
1.3
—
1626.8 °C
—
Albert Ghiorso
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.
Lawrencium-256
Half-life: About 27 seconds. Isotope used in the 2015 first-ionization-energy measurement experiment.Lawrencium-262
Half-life: About 3.6 hours. Long-lived isotope often listed in reference tables.Lawrencium-266
Half-life: About 22 hours. Among the longest-lived lawrencium isotopes; reported uncertainty is large.- Testing relativistic electronic-structure calculations
- Ionization energy and actinide-series boundary research
- Nuclear decay and heavy-ion reaction studies
Lawrencium has no biological role. It is synthetic, radioactive and produced atom by atom for research.
- 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.
- 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.
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.
Why is lawrencium’s electron configuration unusual?
Relativistic effects make the 7p orbital competitive, so lawrencium has a 7p¹ ground-state electron.
Is lawrencium an actinide?
Yes. Lawrencium is usually treated as the final actinide.