Neptunium vs Curium

PropertyNp NeptuniumCm Curium
Atomic number9396
SymbolNpCm
NameNeptuniumCurium
Categoryactinideactinide
Standard Atomic Weight237 u247 u
Period77
GroupN/AN/A
Blockss
Phase at STPsolidsolid
Electron configuration[Rn]7s25f46d1[Rn]7s25f76d1
Oxidation states[2, 3, 4, 5, 6, 7][3, 4, 5, 6]
Electronegativity (Pauling)1.361.3
Electron affinity0.48 eV0.277 eV
Density2.025000e+4 kg/m³1.351000e+4 kg/m³
Melting point643.85 °C1344.85 °C
Boiling point3901.85 °C3126.85 °C
Discovery year19401944