Here's why:

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

* Compounds are formed when two or more different elements chemically combine in a fixed ratio (e.g., lead sulfate, which is made up of lead, sulfur, and oxygen).

Lead sulfate (PbSO₄) is formed by the combination of lead (Pb), sulfur (S), and oxygen (O).