An element is made of only one kind of atom, while a compound contains the atoms of two or more elements. For example, gold is made of only one kind of atom, so it is an element, but water is a mix of hydrogen and oxygen, so it is a compound.
Simply put, the difference between elements and compounds is that elements are made of only one thing, but compounds are made of more than one thing. Compounds are made of different elements. Elements can be found listed on the periodic table of the elements; these are substances that can not be broken down into simpler parts. If broken down to a single atom, sodium would still be sodium, but sodium chloride (aka salt), a compound of sodium and chlorine, would either be a single atom of sodium or a single atom of chlorine.
One way that students can remember the difference between these two things is to look at their name and think about what that word implies. Compounds are made of component elements, while elements are elemental — natural and simple on their own. Compounds are made of different kinds of atoms that are chemically joined, as if they've been pounded together.