Rubidium vs Rutherfordium

PropertyRb RubidiumRf Rutherfordium
Atomic number37104
SymbolRbRf
NameRubidiumRutherfordium
Categoryalkali-metaltransition-metal
Standard Atomic Weight85.4678 u263 u
Period57
Group14
Blockss
Phase at STPsolidsolid
Electron configuration[Kr]5s1[Rn]7s25f146d2
Oxidation states[-1, 1][3, 4]
Electronegativity (Pauling)0.82N/A
Electron affinity0.4859 eV0.65 eV
Density1530 kg/m³2.330000e+4 kg/m³
Melting point39.31 °C2126.85 °C
Boiling point687.85 °C5526.85 °C
Discovery year18611964