Rubidium vs Berkelium

PropertyRb RubidiumBk Berkelium
Atomic number3797
SymbolRbBk
NameRubidiumBerkelium
Categoryalkali-metalactinide
Standard Atomic Weight85.4678 u247 u
Period57
Group1N/A
Blockss
Phase at STPsolidsolid
Electron configuration[Kr]5s1[Rn]7s25f9
Oxidation states[-1, 1][2, 3, 4, 5]
Electronegativity (Pauling)0.821.3
Electron affinity0.4859 eV-0.5 eV
Density1530 kg/m³1.400000e+4 kg/m³
Melting point39.31 °C1049.85 °C
Boiling point687.85 °C-273.15 °C
Discovery year18611949