100 - Fermium actinide
Discovered by Lawrence Berkeley Laboratory in 1953
Fermium 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.
Periodic table
| Shell | Electrons | Orbitals |
|---|---|---|
| 1 | 2 | 2 in 1s |
| 2 | 8 | 2 in 2s + 6 in 2p |
| 3 | 18 | 2 in 3s + 6 in 3p + 10 in 3d |
| 4 | 32 | 2 in 4s + 6 in 4p + 10 in 4d + 14 in 4f |
| 5 | 30 | 2 in 5s + 6 in 5p + 10 in 5d + 12 in 5f |
| 6 | 8 | 2 in 6s + 6 in 6p |
| 7 | 2 | 2 in 7s |
Electron shells
257 u Atomic Mass
14 Group
3 Common Oxidation States
9.7 g/cm³ Density
34 kJ/mol Electron Affinity
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f12 Electron Configuration
[Rn] 5f12 7s2 Electron Configuration (semantic)
1.3 Electronegativity
100 Electrons
6.5 eV First Ionization Energy
627 kJ/mol Ionization Energies
37 Mendeleev Number
7 Number of Shells
157 Neutrons
100 Atomic Number
103 Number of Isotopes
2, 3 Oxidation States
7 Period
Solid Phase
100 Protons