Neptunium vs Copernicium

PropertyNp NeptuniumCn Copernicium
Atomic number93112
SymbolNpCn
NameNeptuniumCopernicium
Categoryactinidetransition-metal
Standard Atomic Weight237 u285 u
Period77
GroupN/A12
Blockss
Phase at STPsolidgas
Electron configuration[Rn]7s25f46d1[Rn] 7s2 5f14 6d10(predicted)
Oxidation states[2, 3, 4, 5, 6, 7][2, 4]
Electronegativity (Pauling)1.36N/A
Electron affinity0.48 eV-0.8 eV
Density2.025000e+4 kg/m³1.400000e+4 kg/m³
Melting point643.85 °C-273.15 °C
Boiling point3901.85 °C-165.15 °C
Discovery year19401996