What is a Nuclear Reaction? - Definitions & Types

 You may have heard of nuclear reactions in the news, but what are they? Nuclear reactions are complex processes that occur within an atom’s nucleus and result in the transformation of one type of atomic nucleus into another type of atomic nucleus. A nuclear reaction can be either an elementary nuclear reaction or a compound nuclear reaction, although they both involve the same types of reactions and equations. In this article, we will explore these nuclear reactions further so you have an understanding of what they are and how they occur.

Introduction to the Atom

The atom is the basic unit of matter that makes up all living and non-living things. Atoms are incredibly small; they are so small that it would take about 3 million atoms lined up side by side to equal the width of a human hair. The term atom comes from the Greek word for indivisible, because it was once thought that atoms were the smallest things in the universe and could not be divided.

Radioactive Decay

All matter is made up of atoms, which are in turn made up of protons and neutrons. These particles are held together by the strong force. The strong force is also responsible for binding nucleons together to form atoms in the first place.

Fission (Breaking Up Atoms)

In nuclear fission, an atomic nucleus is split into two or more smaller nuclei. This process releases a lot of energy. Fission can happen spontaneously in some heavy nuclei, or it can be induced by bombarding the nucleus with subatomic particles. When fission happens, the resulting nuclei and released energy can cause a chain reaction.

Fusion (Combining Atoms)

In nuclear fusion, two atoms join together to form a larger atom. This process releases energy and is used to power the sun and stars. Fusion reactions occur when the nuclei of two atoms collide and fuse together. The resulting nucleus has a lower mass than the sum of the two original nuclei. This difference in mass is released as energy.

Exothermic vs Endothermic Reactions

In an exothermic reaction, heat is released to the surroundings. In contrast, an endothermic reaction absorbs heat from the surroundings. Exothermic reactions are more common than endothermic reactions. Endothermic reactions often have a negative sign in front of the ΔH value, while exothermic reactions have a positive sign.