Rubidium vs Europium

PropertyRb RubidiumEu Europium
Atomic number3763
SymbolRbEu
NameRubidiumEuropium
Categoryalkali-metallanthanide
Standard Atomic Weight85.4678 u151.964 u
Period56
Group1N/A
Blockss
Phase at STPsolidsolid
Electron configuration[Kr]5s1[Xe]6s24f7
Oxidation states[-1, 1][0, 2, 3]
Electronegativity (Pauling)0.82N/A
Electron affinity0.4859 eV0.116 eV
Density1530 kg/m³5240 kg/m³
Melting point39.31 °C821.85 °C
Boiling point687.85 °C1528.85 °C
Discovery year18611896