What do we call a substance made up of two or more different elements chemically joined together?

A substance made up of two or more different elements chemically joined together is known as a compound. Compounds form when atoms of different elements bond together through chemical reactions, creating new substances with distinct properties that are different from the individual elements they are composed of.

For example, water (H₂O) is a compound formed from hydrogen and oxygen atoms bonded together. Each compound has a specific chemical formula that represents the elements and the ratios in which they combine.

Understanding compounds is fundamental in chemistry because they make up a majority of the substances studied in the field. Molecules, while similar, can refer to any group of atoms bonded together, including those made of the same element. Elements refer to pure substances comprised of only one type of atom, and solutions are homogeneous mixtures that can contain compounds or elements but are not chemically bonded.