Berkelium vs Fermium

PropertyBk BerkeliumFm Fermium
Atomic number97100
SymbolBkFm
NameBerkeliumFermium
Categoryactinideactinide
Standard Atomic Weight247 u257 u
Period77
GroupN/AN/A
Blockss
Phase at STPsolidsolid
Electron configuration[Rn]7s25f9[Rn] 5f12 7s2
Oxidation states[2, 3, 4, 5][2, 3]
Electronegativity (Pauling)1.31.3
Electron affinity-0.5 eV0.339 eV
Density1.400000e+4 kg/m³9700 kg/m³
Melting point1049.85 °C1526.85 °C
Boiling point-273.15 °C-273.15 °C
Discovery year19491952