Rubidium vs Terbium

PropertyRb RubidiumTb Terbium
Atomic number3765
SymbolRbTb
NameRubidiumTerbium
Categoryalkali-metallanthanide
Standard Atomic Weight85.4678 u158.92535 u
Period56
Group1N/A
Blockss
Phase at STPsolidsolid
Electron configuration[Kr]5s1[Xe]6s24f9
Oxidation states[-1, 1][0, 1, 2, 3, 4]
Electronegativity (Pauling)0.82N/A
Electron affinity0.4859 eV1.124 eV
Density1530 kg/m³8230 kg/m³
Melting point39.31 °C1355.85 °C
Boiling point687.85 °C3229.85 °C
Discovery year18611843