What is the name given to the force of attraction between the nucleons in the nucleus of an atom?

1. Analyze the question The question asks for the name of the force that holds nucleons (protons and neutrons) together inside the nucleus.

2. Explain the concept The nucleus contains protons, which are positively charged, packed into a tiny space. Since like charges repel, the protons should push each other apart through the electrostatic (Coulomb) force. Yet the nucleus stays together, so there must be a much stronger attractive force acting between nucleons.

This force is called the nuclear force, also known as the strong nuclear force. Its features are:

• It is very strong, much stronger than the electrostatic repulsion between protons at nuclear distances.
• It has a very short range, about 10⁻¹⁵ m (1 femtometre).
• It acts between all nucleons, whether proton-proton, neutron-neutron, or proton-neutron.
• It does not depend on electric charge.

3. Work through the options

• A. Gravitational force: This acts between masses but is extremely weak at the nuclear scale, so it cannot hold the nucleus together.
• B. Electrostatic force: This is repulsive between protons, so it tends to break the nucleus apart rather than bind it.
• C. Magnetic force: This acts on moving charges and is not the binding force in the nucleus.
• D. Nuclear force: This is the strong, short-range attractive force between nucleons, so it is the correct answer.

4. Answer The correct option is **D. Nuclear force.

5. Exam tip Remember this phrase: "Nucleons are bound by the nuclear force." The name of the force comes from where it acts. If a question mentions a force inside the nucleus that overcomes proton-proton repulsion, the answer is the strong nuclear force.