| Caesium ✕ | |
|---|---|
| Symbol | Cs |
| Atomic number | 55 |
| Chemical property | Alkali metal |
| Origin o the name | the Latin caesius, 'sky blue' |
| Group | 1 |
| Period | 6 |
| Atomic weight (u) | 132.905452 |
| Atomic weight uncertainty (u) | 0 |
| Density (g/cm³) | 1.873 |
| Melting point (K) | 301.59 |
| Boiling point (K) | 944 |
| Heat capacity (J/(g·K)) | 0.242 |
| Electro-negativity | 0.79 |
| Abundance in earth's crust (mg/kg) | 3 |