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19
K
39.098
Potassium
Alkali metals · Group 1 · Period 4
Atomic properties
| Atomic number | 19 |
|---|---|
| Symbol | K |
| Standard atomic weight | 39.098 |
| Classification | Alkali metals |
| Group | 1 |
| Period | 4 |
| Block | s-block |
| Electron configuration | [Ar] 4s1 |
| Electronegativity (Pauling) | 0.82 |
| Common oxidation states | +1 |
Physical properties
| Phase at 20 °C | Solid |
|---|---|
| Density | 0.862 g/cm³ |
| Melting point | 63.5 °C |
| Boiling point | 759 °C |
| Discovered | 1807 |
| CAS number | — |