Rubidium

Symbol | Rb
Latin name | Rubidium
Atomic number | 37
Period | 5
Element category | Alkali metals
Relative atomic mass | 85.4678
Group | I.A
Electronegativity | 0.8
Oxidation numbers | 1
Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 5s1
Density [g/cm3] | 1.532
State | Solid
Melting point [°C] | 38.89
Boiling point [°C] | 688
Critical point [°C] | 1820
Critical pressure [MPa] | 16
Atomic radius [pm] | 265
Covalent radius [pm] | 211
Thermal conductivity [W m-1K-1] | 58.2
Heat capacity [J K-1g-1] | 0.363
Discovery | 1861
Hardness [Mohs scale] | 0.3
Brinell hardness [MPa] | 0.216
Young's modulus [GPa] | 2.4
Electrical conductivity [S m-1] | 4.78 · 107
1.st ionization energy [eV] | 4.1771
2.nd ionization energy [eV] | 27.28
3.rd ionization energy [eV] | 40.0
Stable isotopes | 2
Unstable isotopes | 19