# How do you distinguish between atoms and molecules?

Jul 2, 2016

An atom is the smallest part of an element. A molecule consists of two or more atoms.

#### Explanation:

Atoms

For example, helium consists of only $\text{He}$ atoms.

They are the smallest part of helium that can exist and still be considered helium.

Molecules

Substances that contain more than one atom are called molecules.

Some common examples are hydrogen (${\text{H}}_{2}$), oxygen (${\text{O}}_{2}$), nitrogen (${\text{N}}_{2}$), and chlorine (${\text{Cl}}_{2}$).

If the molecules consist of only one type of atom, we call them elements.

Other molecules are nitrogen monoxide ($\text{NO}$), water ($\text{H"_2"O}$), nitrogen dioxide (${\text{NO}}_{2}$), and carbon dioxide (${\text{CO}}_{2}$).

Molecules that consist of more than one type of atom are called compounds.