An example of an atom is a single particle of any element on the periodic table. Carbon, for instance, consists solely of identical carbon atoms. Atoms are the smallest distinct unit of matter, and they cannot be broken down by chemical means.
An atom consists of electrons that orbit a nucleus, which contains protons and neutrons. Atoms can be neutral or have charges; the latter are called ions and can be either negatively or positively charged. Cations are positively charged ions, while anions are negatively charged.
Compounds are made up of different types of atoms depending on its chemical formula. For example, sodium chloride, or NaCl, is made up of sodium and chlorine atoms.