What element is represented by the symbol 'K'?

The element represented by the symbol “K” is potassium.

Potassium’s symbol comes from kalium, the Neo-Latin name used in several European languages. Its English name comes from potash, an old material made by extracting soluble salts from the ashes of burned plants. The difference between the English name and the symbol is why K can seem unintuitive.

Potassium is a soft, silvery-white alkali metal with atomic number 19. It has one electron in its outer shell, which it readily loses to form the potassium ion K⁺. In nature, potassium is therefore found mainly in compounds and minerals rather than as free metal.

The element was isolated by Humphry Davy in 1807 through electrolysis. Metallic potassium reacts vigorously with water, producing heat and hydrogen that can ignite, but potassium compounds are essential nutrients for plants, animals, and humans. Potassium salts are common in foods and fertilizers.