Here's why:

* Elements are pure substances that cannot be broken down into simpler substances by chemical means. Examples include oxygen (O), carbon (C), and chlorine (Cl).

* Compounds are formed when two or more elements chemically combine in a fixed ratio.

Cl₂ represents a molecule of chlorine gas. It consists of two chlorine atoms (Cl) bonded together. Since it's composed of two identical atoms of the same element, it's considered a diatomic molecule.