* Elements are the simplest pure substances that cannot be broken down further by chemical means (e.g., oxygen, nitrogen, carbon).

* Compounds are formed when two or more elements combine chemically in a fixed ratio (e.g., water (H₂O), sodium chloride (NaCl)).

* Mixtures are combinations of substances that are not chemically bonded and can be separated by physical means (e.g., salt and pepper, air).

Ammonium nitrate (NH₄NO₃) is formed by the chemical combination of nitrogen, hydrogen, and oxygen in a specific ratio. This means it is a compound.