| From Wikipedia, the free encyclopediaFermium is a synthetic element with symbol Fm and atomic number 100. It is a member of the actinide series. It is the heaviest element that can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic quantities, although pure fermium metal has not yet been prepared. | |||||||||
Fermium in the periodic table | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Symbol | Fm | ||||||||
| Atomic number | 100 | ||||||||
| Group | 0 | ||||||||
| Period | 7 | ||||||||
| Block | f | ||||||||
| Element category | Actinide | ||||||||
Physical properties | |||||||||
| Phase at STP | Solid | ||||||||
| Density | g/cm3 | ||||||||
| Atomic weight | 257 u | ||||||||
| Melting point | 1800 K 1526.85 °C 2780.33 °F | ||||||||
| Boiling point | K °C °F | ||||||||
Atomic properties | |||||||||
| Electronegativity (Pauling Scale) | 1.3 | ||||||||
| Electron affinity | 33.96 kJ/mol | ||||||||
| Oxidation states | +2, +3 () | ||||||||
| Ionization energies |
| ||||||||
Electron configuration | |||||||||
| Elektronkonfiguration (shorthand) | [Rn] 5f12 7s2 | ||||||||
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f12 6s2 6p6 7s2 | ||||||||
| Electrons per shell | 2, 8, 18, 32, 30, 8, 2 | ||||||||
History | |||||||||
| Discovered | 1952 | ||||||||
| Discovered by | Lawrence Berkeley National Laboratory | ||||||||