Potassium ion
Charge: 1+ · Type: Cation · Molar mass: 39.098 g/mol
Made of: potassium
How it forms
Potassium has one valence electron, which it readily loses to reach the stable electron configuration of argon. The resulting K+ ion is larger than Na+, and cells use this size difference to move the two ions in opposite directions.
Naming note
K+ is named the potassium ion, from the element name. Its symbol K comes from the Latin kalium, which is why the ion is never called the kalium ion in English.
Examples in compounds
Potassium chloride
Potassium nitrate
Potassium hydroxide