Americium vs Einsteinium

PropertyAm AmericiumEs Einsteinium
Atomic number9599
SymbolAmEs
NameAmericiumEinsteinium
Categoryactinideactinide
Standard Atomic Weight243 u252 u
Period77
GroupN/AN/A
Blockss
Phase at STPsolidsolid
Electron configuration[Rn]7s25f7[Rn]7s25f11
Oxidation states[2, 3, 4, 5, 6, 7][2, 3, 4]
Electronegativity (Pauling)1.31.3
Electron affinity0.1 eV-0.3 eV
Density1.369000e+4 kg/m³8840 kg/m³
Melting point1175.85 °C859.85 °C
Boiling point2010.85 °C-273.15 °C
Discovery year19441952