Air is a mixture of gases, not a compound. Here's a breakdown of its major components:

* Nitrogen (N2): About 78% of the atmosphere.

* Oxygen (O2): About 21% of the atmosphere. Crucial for respiration.

* Argon (Ar): About 0.9% of the atmosphere.

* Carbon dioxide (CO2): About 0.04% of the atmosphere. A greenhouse gas.

* Other gases: This includes trace amounts of neon, helium, methane, krypton, hydrogen, xenon, and ozone.

Note: The composition of air can vary slightly depending on altitude, location, and pollution levels.