Erbium vs Polonium

PropertyEr ErbiumPo Polonium
Atomic number6884
SymbolErPo
NameErbiumPolonium
Categorylanthanidemetalloid
Standard Atomic Weight167.259 u209 u
Period66
GroupN/A16
Blocksp
Phase at STPsolidsolid
Electron configuration[Xe]6s24f12[Xe]6s24f145d106p4
Oxidation states[0, 1, 2, 3][-2, 2, 4, 5, 6]
Electronegativity (Pauling)1.242
Electron affinity0.312 eV1.9 eV
Density9070 kg/m³9320 kg/m³
Melting point1528.85 °C253.85 °C
Boiling point2867.85 °C961.85 °C
Discovery year18431898