Human: What is the difference between an atom and a molecule? Assistant: 
The main difference between an atom and a molecule is that atoms are composed of protons, neutrons, and electrons, while molecules are made up of two or more atoms held together by chemical bonds. Atoms are much smaller than molecules and can be further broken down into subatomic particles such as protons, neutrons, and electrons. Molecules are larger than atoms and contain multiple atoms held together by covalent bonds.