Cesium |
| Symbol | Cs |
|---|---|
| Latin name | Caesium |
| Atomic number | 55 |
| Period | 6 |
| Element category | Alkali metals |
| Relative atomic mass | 132.90543 |
| Group | I.A |
| Electronegativity | 0.7 |
| Oxidation numbers | 1 |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 6s1 |
| Density [g/cm3] | 1.873 |
| State | Solid |
| Melting point [°C] | 28.40 |
| Boiling point [°C] | 700 |
| Critical point [°C] | 1665 |
| Critical pressure [MPa] | 9.4 |
| Atomic radius [pm] | 298 |
| Covalent radius [pm] | 225 |
| Thermal conductivity [W m-1K-1] | 35.9 |
| Heat capacity [J K-1g-1] | 0.24 |
| Discovery | 1860 |
| Hardness [Mohs scale] | 0.2 |
| Young's modulus [GPa] | 1.7 |
| Electrical conductivity [S m-1] | 5.3 · 106 |
| 1.st ionization energy [eV] | 3.8939 |
| 2.nd ionization energy [eV] | 25.10 |
| Stable isotopes | 2 |
| Unstable isotopes | 19 |