Fermium (Fm)
Fermium (Fm) is element 100, an actinide. Atomic mass 257, configuration [Rn] 5f¹² 7s². Properties, isotopes, oxidation states, uses and history, with an interactive 3D atom model.
Key facts
| Atomic number | 100 |
|---|---|
| Symbol | Fm |
| Standard atomic weight | 257 |
| Category | Actinide |
| Period | 7 |
| State at room temperature | Solid |
| Electron configuration | [Rn] 5f¹² 7s² |
| Valence electrons | 2 (Variable) |
| Common oxidation states | +3 |
| Common ions | No common ions |
| First ionization energy | 627 kJ/mol |
| Melting point | 852°C |
Common uses
- Research only
Where it matters
- Limit of neutron capture (Heaviest element formable by bombardment)
Hazards
- Highly radioactive
History
| Discovered | 1952 |
|---|---|
| Discovered by | Albert Ghiorso et al. |
| Name | Enrico Fermi |