What is the difference between compound and simple substances?

Answer

Hi Paula,

Simple substances are molecules made up of only one element from the periodic table of the elements (also known as Mendeleev’s table). Examples here are, for example, oxygen gas (O₂) or hydrogen gas (H₂). Pure metals are also simple substances, because they consist only of the metal itself. For example, pure gold consists only of the element gold (Au).

Compound substances are molecules that consist of 2 or more different atoms from the periodic table. An example is, for example, water. It is a composite substance because it consists of both two atoms of hydrogen and one atom of oxygen (H₂Oh so).

Do not confuse this terminology with pure substances versus mixtures. A pure substance is a substance consisting of only one kind of molecules, which can be a simple or compound substance in itself. Mixtures are mixtures of pure substances. For example, water is a pure substance, but salt water is a mixture (namely of water and salt).

Regards,
Benjamin