Molecules and Compounds

A group of two or more atoms forms a molecule. For instance, two atoms of hydrogen (H) form a hydrogen molecule (H2). When hydrogen unites chemically with oxygen, the result is water (H2O), which is compound. A compound, then consists of two or more elements. The molecule is the smallest unit of a compound with the same chemical characteristic. We can have molecules for either elements or compounds. However, atoms exist only for the elements.