How many atoms is in a molecule of an atom?

Answer 1

Gases such as helium, neon have one atom in their stable molecules, compounds such as oxygen, nitrogen, bromine have two, ozone has three, phosphorus has four and sulfur has basically eight (and it forms various crown like structures with differed numbers of atoms).

Answer 2

A molecule is comprised of atoms bonded together. The number of atoms in a molecule depends on the specific chemical compound. For example, water (H2O) consists of two hydrogen atoms and one oxygen atom, so a molecule of water contains three atoms.