Difference Between Atom and Ion


The smallest unit of matter. It is indivisible and consists of neutrons, electrons and protons. Atoms can take part in chemical reactions. Combination of atoms together forms molecule. Always the number of protons and electrons are equal. Independent existence in a solution may or may not be possible. Nucleus of the atom is formed by protons and neutrons. Surrounding the nucleus are the electrons.


Atoms where the electrons and protons are not equal are called ions. Ions are charged particles. They can be either positively charged ions or negatively charged ions. If an atom is electrically charged the it is called ion. If an atom contains maximum number of electrons than protons, then it is called anion. If an atom contains maximum number of protons than electrons, then it is called cation. Independent existence in a solution. When an atom gains or loses electrons, ion is formed.

To make you understand how atom and ion are different from each other, here are the some of the major differences between atom and ion:

Difference between Atom and Ion



Smallest unit of element

Single particle or collection of particles

Takes part in chemical reaction

Cannot participate in chemical reaction

Not independent in solution

Is independent in solution

Atoms form molecule

Ions form electrovalent bond

Electrons and protons are equal

Electrons and protons are unequal



These were some of the important difference between ion and atom. To know differences between other topics in chemistry you can register to BYJU’S or download our app for simple and interesting content. India’s largest k-12 learning app with top notch teachers from across the nation with excellent teaching skills. Find notes, question papers for other subjects like Mathematics, Physics, Biology and various competitive exams as well. Enjoy learning with great experience. Learning is no more boring with BYJU ‘S.

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