Niobium vs Polonium

PropertyNb NiobiumPo Polonium
Atomic number4184
SymbolNbPo
NameNiobiumPolonium
Categorytransition-metalmetalloid
Standard Atomic Weight92.90637 u209 u
Period56
Group516
Blocksp
Phase at STPsolidsolid
Electron configuration[Kr]5s14d4[Xe]6s24f145d106p4
Oxidation states[-3, -1, 0, 1, 2, 3, 4, 5][-2, 2, 4, 5, 6]
Electronegativity (Pauling)1.62
Electron affinity0.893 eV1.9 eV
Density8570 kg/m³9320 kg/m³
Melting point2476.85 °C253.85 °C
Boiling point4743.85 °C961.85 °C
Discovery year18011898