What are Nucleons?

A nucleon is one of the particles of the atomic nucleus. Each atomic nucleus includes one or more Nucleons. These are surrounded by one or more electrons. They occupy small space within the nucleus. Every atom is made up of nucleons which are further divided into electrons, protons, and neutrons that orbit the nucleus. An atom is just like a mini-solar system, with electrons orbiting a central star which is the nucleus, composed of nucleons.


Protons and neutrons are the best-known components of atomic nuclei. They can be found on their own not being part of the larger nucleus. A proton is the nucleus of the hydrogen-1 atom on its own which is the most abundant isotope of hydrogen.

Binding energy per nucleon

Nuclei consist of neutron and protons, but the mass of the nucleus is less than the sum of individual masses of the protons and neutrons.The difference is the measure of binding energy per nucleon that holds the nucleons together. The binding energy can be determined from the Einstein relationship:

Nuclear binding energy = Δmc2

Δm = 0.0304 u for alpha particles and gives a binding energy of 28.3 MeV.

Properties of Nucleons

A neutron is not stable on its own, but it can be found in nuclear reactions and used in scientific analysis. Both proton and neutron consist of three quarks. The proton has two up quarks( the lightest of all quarks and a  major constituent of matter and a type of elementary particle) and one down quark( the second lightest), while a neutron is made up of one up quark and two down quarks.

These are an integral part of the atomic nucleus since they cannot exist as independent nucleons. The atomic nucleus holds the nucleons with a strong force. However when the force is broken, it can produce a lot of power, and that power is termed as the nuclear energy which is similar to what is used in nuclear bombs. Nucleons present in radioactive decay substances such as uranium can be harmful since it can spread alpha radiation in a few seconds.

Practise This Question

A system which exchanges both matter & energy with the surrounding is called a closed system.