Praseodymium vs Polonium

PropertyPr PraseodymiumPo Polonium
Atomic number5984
SymbolPrPo
NamePraseodymiumPolonium
Categorylanthanidemetalloid
Standard Atomic Weight140.90766 u209 u
Period66
GroupN/A16
Blocksp
Phase at STPsolidsolid
Electron configuration[Xe]6s24f3[Xe]6s24f145d106p4
Oxidation states[0, 1, 2, 3, 4, 5][-2, 2, 4, 5, 6]
Electronegativity (Pauling)1.132
Electron affinity0.962 eV1.9 eV
Density6770 kg/m³9320 kg/m³
Melting point930.85 °C253.85 °C
Boiling point3519.85 °C961.85 °C
Discovery year18851898