Samarium vs Polonium

PropertySm SamariumPo Polonium
Atomic number6284
SymbolSmPo
NameSamariumPolonium
Categorylanthanidemetalloid
Standard Atomic Weight150.36 u209 u
Period66
GroupN/A16
Blocksp
Phase at STPsolidsolid
Electron configuration[Xe]6s24f6[Xe]6s24f145d106p4
Oxidation states[0, 1, 2, 3][-2, 2, 4, 5, 6]
Electronegativity (Pauling)1.172
Electron affinity0.156 eV1.9 eV
Density7520 kg/m³9320 kg/m³
Melting point1073.85 °C253.85 °C
Boiling point1793.85 °C961.85 °C
Discovery year18781898