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37Rb85.468
Rubidium
Alkali MetalRubidium is a chemical element with symbol Rb and atomic number 37. Rubidium is a soft, silvery-white metallic element of the alkali metal group, with an atomic mass of 85.4678. Elemental rubidium is highly reactive, with properties similar to those of other alkali metals, such as very rapid oxidation in air.
Phase: SolidAppearance: grey white
2, 8, 18, 8, 1
Physical Properties
Atomic Mass85.46783 u
Density1.532 g/cm³
Melting Point312.45 K
Boiling Point961 K
Molar Heat31.06 J/(mol·K)
Period5
PhaseSolid
Chemical Properties
Electron Configuration1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1
Semantic Config[Kr] 5s1
Shells2, 8, 18, 8, 1
Electron Affinity46.884 kJ/mol
Electronegativity0.82
Ionization Energies
IE1: 403 kJ/molIE2: 2633 kJ/molIE3: 3860 kJ/molIE4: 5080 kJ/molIE5: 6850 kJ/molIE6: 8140 kJ/molIE7: 9570 kJ/molIE8: 13120 kJ/molIE9: 14500 kJ/molIE10: 26740 kJ/mol
Discovery
Discovered byRobert Bunsen