Here's why:

* Elements are the simplest forms of matter and cannot be broken down further by chemical means. Examples include carbon (C), oxygen (O), and hydrogen (H).

* Compounds are formed when two or more different elements combine chemically in a fixed ratio. This means the elements are bonded together and cannot be easily separated by physical means.

* The smallest unit of a compound is called a molecule, which is a group of two or more atoms held together by chemical bonds.

Examples of compounds:

* Water (H₂O): Two hydrogen atoms bonded to one oxygen atom.

* Carbon dioxide (CO₂): One carbon atom bonded to two oxygen atoms.

* Sodium chloride (NaCl): One sodium atom bonded to one chlorine atom.

Let me know if you have any other chemistry questions!