An element is a pure substance that cannot be broken down into simpler substances by chemical means. An element is composed of only one type of atom. A compound is a substance that is composed of two or more elements chemically combined. Compounds can be broken down into their constituent elements by chemical means.

Examples of elements:

* Oxygen

* Hydrogen

* Carbon

* Nitrogen

* Sodium

Examples of compounds:

* Water (H2O)

* Carbon dioxide (CO2)

* Sodium chloride (NaCl)

* Sugar (C12H22O11)