Potassium (K)
Potassium (K) is element 19 of the periodic table, an alkali metal in period 4 and group 1. Its standard atomic weight is 39.0983, so one mole of potassium atoms has a mass of 39.0983 g. At room temperature it is a solid; it melts at 63.38 °C and boils at 758.85 °C.
| Atomic number | 19 |
|---|---|
| Symbol | K |
| Standard atomic weight | 39.0983 |
| Molar mass | 39.0983 g/mol |
| Category | Alkali metal |
| Group | 1 |
| Period | 4 |
| Block | s-block |
| Electron configuration | [Ar] 4s1 |
| Oxidation states | +1 |
| Electronegativity (Pauling) | 0.82 |
| Atomic radius (van der Waals) | 275 pm |
| First ionisation energy | 4.341 eV (418.8 kJ/mol) |
| Electron affinity | 0.501 eV |
| State at room temperature | Solid |
| Melting point | 336.53 K (63.38 °C) |
| Boiling point | 1032 K (758.85 °C) |
| Density | 0.89 g/cm³ |
| Discovered | 1807 |
Group 1
Calculate with Potassium
Atomic weight: IUPAC CIAAW standard atomic weight. Other properties: PubChem (U.S. National Library of Medicine, public domain). Values such as melting point and radius depend on how they were measured; check a data book for precise work.