AAT Bioquest

What are the differences between atoms and molecules?

Posted December 13, 2022


Basis of differentiation




Atoms are the smallest units of matter that still retain the characteristic properties of their element

Molecules are a combination of two or more atoms that are held together by chemical bonds


An atom is made up of three subatomic particles – protons, neutrons, and electrons

A molecule is made up of two or more atoms, which can be of the same element or of different elements 


Atoms are not stable by themselves in nature due to the presence of electrons in the outer shells. They attain stability by forming chemical bonds with other atoms. 

Molecules are formed by atoms to attain stability. They are stable by themselves in nature. 


Atoms cannot be separated into subatomic particles by chemical reactions. Separation is only possible by nuclear reactions.

Molecules can be separated into atoms by chemical reactions.


All atoms, except the noble elements, exhibit some amount of reactivity.

Molecules exhibit less reactivity than atoms. 


Hydrogen (H)

Calcium (Ca)

Sodium (Na)

Chlorine (Cl)

Iron (Fe)

Water (H20)

Carbon dioxide (C02)

Glucose (C6H12O6 )

Table salt (NaCl)

Calcium Oxide (CaO)

Additional resources

Rydberg-Stark deceleration of atoms and molecules

ReadiUse™ Tyramide (TSA)/Styramide (PSA) Optimized Reaction Buffer