Strontium vs Polonium

PropertySr StrontiumPo Polonium
Atomic number3884
SymbolSrPo
NameStrontiumPolonium
Categoryalkaline-earth-metalmetalloid
Standard Atomic Weight87.62 u209 u
Period56
Group216
Blocksp
Phase at STPsolidsolid
Electron configuration[Kr]5s2[Xe]6s24f145d106p4
Oxidation states[1, 2][-2, 2, 4, 5, 6]
Electronegativity (Pauling)0.952
Electron affinity0.052 eV1.9 eV
Density2640 kg/m³9320 kg/m³
Melting point776.85 °C253.85 °C
Boiling point1381.85 °C961.85 °C
Discovery year17921898