Difference Between Nuclear Reaction and Chemical Reaction

Main Difference – Nuclear Reaction vs Chemical Reaction

Nuclear Reaction and Chemical Reaction are two types of reactions which fundamentally differ from each other depending on the manner in which the elements take part in these reactions. Chemistry mostly deals with reactions involving exchange and sharing of electrons. However, these reactions don’t usually affect the status of elements’ nuclei. But in the case of a nuclear reaction, the elements that take part in the reaction undergo changes in the sub-atomic particles in their nuclei. Therefore, the main difference between nuclear reaction and chemical reaction can be simply explained as the behavior of the  elements involved in the reactions; only orbital electrons take part in chemical reactions whereas, in nuclear reactions, the nuclei of elements are involved.

What is Nuclear Reaction

A nuclear reaction takes place when a nucleus of an atom collides with another nucleus or with a sub-atomic particle (such as protons, neutrons, and high energy electrons). Generally, after this collision, one or more nuclides are produced, which are different to the ones that were at the beginning of the process. Therefore, during a nuclear reaction process, the elements at the start change into different elements through a change in the sub-atomic particle composition of the nucleus. In nuclear reactions, it is possible for a heavy nucleus to split into smaller atoms and also for two different nuclei to get together to form a heavier atom. In this case, the first type is called ‘nuclear fission’ and the latter is known as ‘nuclear fusion’ reaction.

Both these types of nuclear reactions are used in nuclear weapons and nuclear fission reactions are often performed in nuclear reactors. Nuclear reactions are often seen in unstable and radioactive elements. However, radioactive decay, which is a natural phenomenon, is not considered as a nuclear reaction. Therefore, as the definition suggests, these reactions are performed on purpose most of the time. Cosmic rays colliding with matter can be taken as an example of a naturally occurring nuclear reaction.Main Difference - Nuclear Reaction vs Chemical Reaction

What is Chemical Reaction

These are reactions that involve the outer shell electrons among atoms. In this case, what changes is the bonding of each element to each other while keeping the type of elements a constant. The atoms/molecules that take part in the reactions go through a series of breaking and making bonds. If bonds are due to electrostatic forces, they are called ionic bonds, and if it is due to the sharing of electrons, the bonds are known as covalent bonds. The atoms/molecules at the beginning are called reactants, and the resulting molecules are called products.

Most reactions move in the forward direction, and some also move backward till it reaches a point of equilibrium. This kind of reactions is called equilibrium reaction. Moreover, some reactions are spontaneous, and they do not require an input of energy. In contrast, the non-spontaneous reactions need an external energy supply to drive the reaction forward. This energy will help the reactants overcome the energy barrier inherent in any reaction. Each chemical reaction can be written as an equation with the reactants and the products on either side. And the detail step-by-step pathway of a reaction is called its ‘mechanism.’ Reactions often take place in multistep. External factors such as heat and the use of catalysts can affect the rate of a reaction.Difference Between Nuclear Reaction and Chemical Reaction

Difference Between Nuclear Reaction and Chemical Reaction


Nuclear reactions are reactions where the nuclei of atoms take part in the reaction.

In Chemical reactions, it is the electrons in the outer shells that take part in the reaction.

Elemental Composition

The elemental composition changes during a nuclear reaction resulting different types of nuclides than at the beginning.

The elemental composition of a chemical reaction stays the same before and after the reaction. It is only the bonding order that changes.

Energy Transformation

Nuclear fission reactions release a massive amount of energy.

Chemical reactions deal with a quantity of energy that is sufficient to elevate the reactants above their energy barrier.


Nuclear reactions only occur among highly unstable atoms and are usually created on purpose.

Chemical reactions are the basis of life, and it occurs all around/in us at any given time.

Image Courtesy:

“Combustion reaction of methane” by Jynto Robert A. Rohde Jacek FH – (CC BY-SA 3.0) via Commons 

“Li6-D Reaction” by Sakurambo – Own work, based on Image: Li6-D Reaction.png. (CC BY-SA 3.0) via Commons

About the Author: admin