Question

How could you distinguish an element from a compound?

Answer 1

If it is on the periodic table, it is an element.

Explanation:

An element is a pure substance and is found on the periodic table. If you have more than one element chemically bonded, it is a compound.

Examples
Hydrogen, oxygen, and iron are all elements.

`H_"2"O` is a compound because it is hydrogen and oxygen chemically bonded. You won't find a symbol of `H_"2"O` on the periodic table.

Similarly, `Fe_"2"O_"3"` is a chemical compound made of elements.