Difference Between An Atom And A Molecule

What is an Atom?

An atom can be defined as the smallest constituent particle of an element which showcases independent existence.

Example: Ne, O

What is a Molecule?

A molecule can be defined as the combinations of two or more atoms which are held together by chemical bonds. A molecule is the smallest portion of a substance which showcases all the properties of the substance. On breaking down a molecule further, we see properties of the constituent elements.

Example: O2, HCl

Differences between Atoms & Molecules

Let us discuss the differences between atoms and molecules.

Atoms vs molecules





Most fundamental and smallest part that can exist of an element.

Two or more atoms chemically bonded together.


Oxygen – O

Phosphorus – P

Sulphur – S

Hydrogen – H

Oxygen – O2

Phosphorus – P4

Sulphur – S8

Water – H2O


Smallest particle with properties of an element.

Combination of two or more atoms.


An atom may not always be stable in nature due to the presence of electrons in the outer shells.

Molecules are formed to attain stability.

Constituent Elements

Protons, Electrons & Neutrons

Two or more atoms of the same or different elements


Except for the noble elements, atoms of all elements showcase a certain level of reactivity.

Compared to a molecule, the level of reactivity is less as some of the valence points are filled by electrons of combined elements.

Thus, here we have discussed about some of the difference between atoms and molecules. Keep visiting BYJU’S to learn more differences.

Practise This Question

The process by which wet clothes dry up is called as: