Lawrencium (Lr)
Lawrencium (Lr) is element 103, an actinide. Atomic mass 266, configuration [Rn] 5f¹⁴ 7s² 7p¹. Properties, isotopes, oxidation states, uses and history, with an interactive 3D atom model.
Key facts
| Atomic number | 103 |
|---|---|
| Symbol | Lr |
| Standard atomic weight | 266 |
| Category | Actinide |
| Period | 7 |
| State at room temperature | Solid |
| Electron configuration | [Rn] 5f¹⁴ 7s² 7p¹ |
| Valence electrons | 3 |
| Common oxidation states | +3 |
| Common ions | No common ions |
| First ionization energy | 443 kJ/mol |
| Melting point | ~1627°C |
Common uses
- Research only
Where it matters
- Periodicity Debate (Placement in d-block vs f-block)
Hazards
- Radioactive
History
| Discovered | 1961 |
|---|---|
| Discovered by | Ghiorso et al. |
| Name | Ernest Lawrence |