Here's the breakdown:

* Element: A substance made up of only one type of atom. Examples include gold (Au), oxygen (O), and carbon (C).

* Compound: A substance made up of two or more different elements chemically combined in a fixed ratio. Examples include water (H₂O), carbon dioxide (CO₂), and sodium chloride (NaCl).

It's important to note that the terms "pure" and "impure" are relative. For instance, a sample of water might be considered "pure" for most purposes, but it might contain dissolved minerals or other impurities that could be significant for specific applications.