What is the role of neutrons?

• A. They orbit the nucleus
• B. They carry a negative charge
• C. They determine the chemical identity of an element
• D. They are uncharged subatomic particles that help hold protons together

Answer: (D)

Neutrons sit in the nucleus alongside protons and have no electric charge. Their main job is to contribute to the nucleus's mass while providing the binding energy that keeps the nucleus intact. The strong nuclear force acts between nucleons and helps hold protons and neutrons together; because neutrons are uncharged, they don’t add electrostatic repulsion. This stabilizing role is why changing the number of neutrons affects nuclear stability and isotopes, not the element’s chemical identity (which is determined by the number of protons). So neutrons are uncharged particles in the nucleus that help hold protons together through the strong nuclear force.