Rubidium vs Niobium

PropertyRb RubidiumNb Niobium
Atomic number3741
SymbolRbNb
NameRubidiumNiobium
Categoryalkali-metaltransition-metal
Standard Atomic Weight85.4678 u92.90637 u
Period55
Group15
Blockss
Phase at STPsolidsolid
Electron configuration[Kr]5s1[Kr]5s14d4
Oxidation states[-1, 1][-3, -1, 0, 1, 2, 3, 4, 5]
Electronegativity (Pauling)0.821.6
Electron affinity0.4859 eV0.893 eV
Density1530 kg/m³8570 kg/m³
Melting point39.31 °C2476.85 °C
Boiling point687.85 °C4743.85 °C
Discovery year18611801