Question

What is the difference between an element and a compound?

Answer 1

An element is made up of atoms that are all the same.

Explanation:

An example is hydrogen, where all molecules are made up of two hydrogen atoms: `H_2`

Compounds are made up out of different types of atoms:
Water `H_2O`, where every molecule is made up out of two hydrogen and one oxygen atom.

If all molecules in a substance are the same, we speak of a pure substance, otherwise it's a mixture.