| Attribute | Potassium × | Cesium × |
|---|---|---|
| Atomic mass (u) | 39.0983 | 132.905452 |
| Standard state | Solid | Solid |
| Oxidation states |
|
|
| Electron configuration | [Ar]4s¹ | [Xe]6s¹ |
| Atomic radius (van der waals) (pm) | 275 | 343 |
| Electronegativity (pauling scale) | 0.82 | 0.79 |
| Electron affinity (eV) | 0.501 | 0.472 |
| Ionization energy (eV) | 4.341 | 3.894 |
| Boiling point (K) | 1032 | 944 |
| Melting point (K) | 336.53 | 301.59 |
| Density (g/cm³) | 0.89 | 1.93 |
| Atomic number | 19 | 55 |
| Group name | Alkali metal | Alkali metal |
| Discovered (year) | 1807 | 1860 |
| Symbol | K | Cs |