Periodic table / Calcium

Overview

Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft gray alkaline earth metal, fifth-most-abundant element by mass in the Earth's crust. The ion Ca2+ is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate.

Electron configuration

The electron configuration of Calcium is [Ar] 4s2, with electron shells of 2, 8, 8, 2.

Physical and chemical properties

Calcium is classified as a alkaline earth metal. It has an atomic mass of 40.078 and exists as a solid at standard conditions.

Real-world uses of Calcium

Calcium and other alkaline earth metals are commonly used in alloys, industrial compounds, and in some cases in medical or agricultural applications.

Interesting facts about Calcium

• Calcium has the atomic number 20 and chemical symbol Ca.
• It belongs to period 4, group 2 of the periodic table.
• Calcium was discovered by Humphry Davy.

Explore Calcium interactively

Want to compare Calcium with other elements or see it highlighted on the full table? Open the interactive periodic table and click on Ca to explore properties, trends, and neighboring elements. You can also test your knowledge with our periodic table quiz game.