Gadolinium vs Berkelium

PropertyGd GadoliniumBk Berkelium
Atomic number6497
SymbolGdBk
NameGadoliniumBerkelium
Categorylanthanideactinide
Standard Atomic Weight157.25 u247 u
Period67
GroupN/AN/A
Blockss
Phase at STPsolidsolid
Electron configuration[Xe]6s24f75d1[Rn]7s25f9
Oxidation states[0, 1, 2, 3][2, 3, 4, 5]
Electronegativity (Pauling)1.21.3
Electron affinity0.132 eV-0.5 eV
Density7900 kg/m³1.400000e+4 kg/m³
Melting point1312.85 °C1049.85 °C
Boiling point3272.85 °C-273.15 °C
Discovery year18861949