Radium vs Americium

PropertyRa RadiumAm Americium
Atomic number8895
SymbolRaAm
NameRadiumAmericium
Categoryalkaline-earth-metalactinide
Standard Atomic Weight226 u243 u
Period77
Group2N/A
Blockss
Phase at STPsolidsolid
Electron configuration[Rn]7s2[Rn]7s25f7
Oxidation states[2][2, 3, 4, 5, 6, 7]
Electronegativity (Pauling)0.91.3
Electron affinity0.096 eV0.1 eV
Density5000 kg/m³1.369000e+4 kg/m³
Melting point699.85 °C1175.85 °C
Boiling point1139.85 °C2010.85 °C
Discovery year18981944