A single molecule of water consists of three atoms. H2O is built from a single atom of oxygen that is single-bonded with two atoms of hydrogen.

Atoms are tiny particles that make up the universe, while molecules are made from atoms (even a single atom). However, both constitute small, identifiable units.

The relationship between atoms and molecules is the way molecules are made up of atoms. Atoms that are in groups of two or more are called molecules.


Water is formed when oxygen and hydrogen atoms combine, and it takes a total of three atoms to make a water molecule. Two of the atoms are hydrogen and the last atom is oxygen, hence the chemical formula H2O.

Hydrogen bonds hold together the atoms in a water molecule. A single water molecule is made up of two hydrogen atoms and one oxygen atom.

The number of atoms in a molecule varies depending on the specific molecule formed. As a rule of thumb, a molecule must be composed of at least two atoms with no maximum amount of atoms as long as all the atoms in the mo...

A polar molecule is a particle consisting of two or more covalently bonded atoms with an asymmetric distribution of charges. This occurs in molecules that are asymmetric along at least one axis when one side contains ato...