Here's a breakdown:

* Not a compound: Air is not a single substance with a fixed chemical formula like water (H₂O) or carbon dioxide (CO₂).

* Mixture of gases: Air is a mixture of several gases, primarily:

* Nitrogen (N₂): About 78%

* Oxygen (O₂): About 21%

* Argon (Ar): About 0.9%

* Carbon dioxide (CO₂): About 0.04%

* Other trace gases: Such as neon, helium, methane, and krypton

This means that the composition of air can slightly vary depending on location and conditions.