Element #20

Calcium

alkaline earth solid Discovered 1808

40.078 Atomic Mass (u)

842 C Melting Point

1484 C Boiling Point

1.55 g/cm3 Density

1 Electronegativity

[Ar] 4s2 Electron Config

4 Period

2 Group

📖 About Calcium

The fifth most abundant element in Earth's crust and essential for bones, teeth, and cellular signaling. Calcium carbonate (limestone) is one of the most important geological materials, forming the shells of marine organisms over millions of years and eventually becoming chalk, limestone, and marble.

🔧 Uses and Applications

Bone and teeth structure (hydroxyapatite)
Cement and concrete (calcium silicates)
Antacids (calcium carbonate)
Calcium supplements
Steel production (removing impurities)

💡 Did You Know?

Fact: The White Cliffs of Dover are made almost entirely of calcium carbonate from the compressed shells of microscopic marine organisms called coccoliths that lived in a warm shallow sea about 70-100 million years ago.