Lr
Lawrencium
Element 103 · 266.12 u
Lawrencium is the last actinide with an anomalous electron configuration.
Physical Properties
| Atomic Mass | 266.12 u |
| Density | 15.6 g/cm³ |
| Melting Point | 1900.0 K |
| Appearance | Metallic (predicted) |
| State at Room Temp | Solid |
Chemical Properties
| Electronegativity | 1.3 (Pauling) |
| 1st Ionization Energy | 470.0 kJ/mol |
| Electron Affinity | -30.04 kJ/mol |
| Oxidation States | +3 |
Atomic Properties
| Electron Configuration | [Rn] 5f14 7s2 7p1 |
Discovery
| Discovered By | Albert Ghiorso, Torbjorn Sikkeland, Almon Larsh, Robert M. Latimer |
| Discovery Year | 1961 |
| Location | Berkeley, California, USA |
| Named After | Named after Ernest O. Lawrence, inventor of the cyclotron |
About Lawrencium
Lawrencium is the last element in the actinide series. Its last electron goes into a 7p orbital rather than 6d, confirmed experimentally in 2015.
Uses & Applications
No practical applications. Scientific research only.
Fun Fact
Lawrencium's electron goes into a 7p orbital rather than 6d -- confirmed experimentally in 2015, a surprise for the actinides.
Isotopes
| Mass Number | Abundance | Half-Life | Stable |
| 260 | - | 2.7 minutes | No |
| 262 | - | 3.6 hours | No |
Electron Configuration
[Rn] 5f14 7s2 7p1