Scientific Tutor

What is the difference between atoms, molecules, and compounds?

Definitions are important to address in this lesson. At this point in chemistry, many people get confused by the words atom, molecule, and compound. An atom is the smallest indivisible part of matter. When you look at a chemical like Rb₂S, 1 Rb is 1 atom. An atom is simply any single element written. So if a single element is written alone like P then it is only an atom. However, that P is also a molecule because it is separate from other chemicals. A molecule is simply any arrangement of atoms that are bound to each other but separate from other chemicals. I like to think of a molecule as a team. Most of the time a team consists of 2 or more people but in theory a team could be only one person. So most of the time a molecule consists of many different atoms, but it is possible for a molecule to consist of only 1 atom. The last definition we need to know is a compound. A compound is when two or more different elements are bound together. Our original example Rb₂S is a compound. Compounds will be by far the most common chemical arrangement you will see.

Examples: Label whether each is a compound, molecule, or atom. You can give more than one answer if needed. VIDEO Atoms, Molecules, and Compounds Examples Video 1.

PRACTICE PROBLEMS: Label whether each is a compound, molecule, or atom. You can give more than one answer if needed.