Element 103
Lawrencium (Lr)
Lawrencium (Lr) is element 103 of the periodic table, a actinide in period 7 (d-block) with an atomic mass of 266 and is a solid at standard conditions.
At a glance
- Atomic number
- 103
- Symbol
- Lr
- Atomic mass
- 266 u
- Category
- Actinides
- Period
- 7
- Block
- d-block
- Phase at STP
- solid
Electron structure
- Electron configuration
- 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 6s2 6p6 5f14 7s2 7p1
- Shorthand configuration
- [Rn] 5f14 7s2 7p1
- Electrons per shell
- 2, 8, 18, 32, 32, 8, 3
- Oxidation states
- +3
Physical properties
- Melting point
- 1900 K
- Density
- 14.4 g/cm3
- Phase
- solid
Atomic properties
- Electronegativity (Pauling)
- 1.3
- First ionization energy
- 479 kJ/mol
- Electron affinity
- -31 kJ/mol
Notable isotopes
| Isotope | Mass | Abundance | Stability |
|---|---|---|---|
| Lr-262 | 262.10961 | — | Half-life 4 hours |
Common uses
- Scientific research only
Discovery
- Year
- 1961
- Discovered by
- Albert Ghiorso
- Country
- USA