Plutonium vs Americium

PropertyPu PlutoniumAm Americium
Atomic number9495
SymbolPuAm
NamePlutoniumAmericium
Categoryactinideactinide
Standard Atomic Weight244 u243 u
Period77
GroupN/AN/A
Blockss
Phase at STPsolidsolid
Electron configuration[Rn]7s25f6[Rn]7s25f7
Oxidation states[2, 3, 4, 5, 6, 7, 8][2, 3, 4, 5, 6, 7]
Electronegativity (Pauling)1.281.3
Electron affinity-0.5 eV0.1 eV
Density1.984000e+4 kg/m³1.369000e+4 kg/m³
Melting point639.85 °C1175.85 °C
Boiling point3227.85 °C2010.85 °C
Discovery year19411944