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 |