Potassium
Potassium is a chemical element with symbol K (derived from Neo-Latin, kalium) and atomic number 19. It was first isolated from potash, the ashes of plants, from which its name is derived. In the Periodic table, potassium is one of seven elements in column (group) 1 (alkali metals):they all have a single valence electron in their outer electron shell, which they readily give up to create an atom with a positive charge - a cation, and combine with anions to form salts.
Physical properties
Values for the element in its standard state.
- Density
- 0.856g/cm³
- Melting point
- 337K
- Boiling point
- 1,032K
- Atomic radius
- 196pm
- Bonding type
- Metallic
- Molar heat
- 29.6J/(mol·K)
Inside the atom
Electron arrangement and the energy behind its behavior.
Full electron configuration
[Ar] represents 18 core electrons. The full view shows them explicitly.
- Electronegativity
- 0.82Pauling scale
- First ionization energy
- 419kJ/mol
- Electron affinity
- 48kJ/mol
- Van der Waals radius
- 275pm
About potassium
- Appearance
- Silvery gray
- Discovery
- 1807 (Humphry Davy)
- Data source
- Read the reference
A missing value means it is unavailable in this reference dataset. Values can vary with measurement method and conditions.