Strontium vs Americium

PropertySr StrontiumAm Americium
Atomic number3895
SymbolSrAm
NameStrontiumAmericium
Categoryalkaline-earth-metalactinide
Standard Atomic Weight87.62 u243 u
Period57
Group2N/A
Blockss
Phase at STPsolidsolid
Electron configuration[Kr]5s2[Rn]7s25f7
Oxidation states[1, 2][2, 3, 4, 5, 6, 7]
Electronegativity (Pauling)0.951.3
Electron affinity0.052 eV0.1 eV
Density2640 kg/m³1.369000e+4 kg/m³
Melting point776.85 °C1175.85 °C
Boiling point1381.85 °C2010.85 °C
Discovery year17921944