Fermium

Actinide · 257.09511 u · group 3, period 7

Fermium · Fm

Atomic number100

SymbolFm

CategoryActinide

Standard stateSolid

Group · Period · Block3 · 7 · f

Electron configuration[Rn] 5f12 7s2

Atomic mass257.09511 u

Atomic radius—

Protons / Neutrons / Electrons100 / 157 / 100

Shells (e⁻ per shell)2, 8, 18, 32, 30, 8, 2

Electronegativity (Pauling)1.3

Ionization energy6.5 eV

Electron affinity—

Oxidation states+3

Melting point1.80e+3 K · 1.53e+3 °C

Boiling point—

Density—

Year discovered1952

CPK color

#B31FBA

State at room temp (25 °C)

solid

Position