Rubidium (Rb)

From Wikipedia, the free encyclopediaRubidium 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.

Rubidium in the periodic table

SymbolRb
Atomic number37
Group1
Period5
Blocks
Element categoryAlkali Metal

Physical properties

Phase at STPSolid
Density1.532 g/cm3
Atomic weight85.4678 u
Melting point312.45 K
39.3 °C
102.74 °F
Boiling point961 K
687.85 °C
1270.13 °F

Atomära egenskaper

Electronegativity (Pauling Scale)0.82
Electron affinity46.884 kJ/mol
Ionization energies
1403 kJ/mol
2 2633 kJ/mol
3 3860 kJ/mol
4 5080 kJ/mol
5 6850 kJ/mol
6 8140 kJ/mol
7 9570 kJ/mol
8 13120 kJ/mol
9 14500 kJ/mol
10 26740 kJ/mol

Electron configuration

Electron configuration1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 5s1
Electrons per shell2, 8, 18, 8, 1

History

Discovered1861
Discovered byRobert Bunsen
Gustav Kirchhoff