You're absolutely right! When metallic calcium (Ca) combines with nonmetallic oxygen (O), it forms a compound called calcium oxide (CaO). This reaction is a classic example of an oxidation-reduction reaction, where calcium loses electrons (oxidation) and oxygen gains electrons (reduction).

Here's the chemical equation for the reaction:

2Ca + O₂ → 2CaO

Here's a breakdown:

* 2Ca: Two atoms of calcium metal.

* O₂: One molecule of diatomic oxygen gas.

* 2CaO: Two molecules of calcium oxide.

Calcium oxide is a white solid commonly known as quicklime. It's a very important industrial chemical used in various applications, including:

* Cement production: A key ingredient in making concrete.

* Steelmaking: Used to remove impurities from iron.

* Water treatment: Helps to neutralize acidic water.

* Agriculture: Used to adjust soil pH.

Let me know if you have any more questions about calcium oxide or other chemical reactions!