Which element has the chemical symbol Ca?

The element with the chemical symbol Ca is calcium. Calcium is an alkaline earth metal with atomic number 20, and its symbol comes from the first two letters of its Latin-derived name.

The word calcium is linked to the Latin calx, meaning “lime,” because calcium compounds such as limestone and calcium carbonate have been known since antiquity. People used these compounds long before chemists understood that they contained a distinct element.

English chemist Humphry Davy first isolated elemental calcium in 1808 by electrolyzing a calcium compound. In nature, calcium is not usually found as a free metal because it reacts readily with air and water. Instead, it appears in minerals, rocks, shells, bones, and teeth.

Calcium is often confused with calcium carbonate, the compound found in limestone, chalk, and seashells. The element itself is a reactive metal, while calcium carbonate is a stable compound. Calcium ions also play vital roles in bones, muscle contraction, nerve signaling, and blood clotting.