Question

Why do stable nuclei never have more protons than neutrons?

• A. Because protons are lighter particle.
• B. Because neutrons have higher gravitational force
• C. Protons participate in coulombic repulsion and neutrons do not.
• D. None of the above

Answer 1

The correct option is C Protons participate in coulombic repulsion and neutrons do not.

Neutrons provide better binding because, unlike protons, they do not participate in coulombic repulsion.

As is known, protons are positively charged ions and repel each other electrically. In nuclei with more than 10 protons or so, the force of repulsion becomes too large. Therefore, excess of neutrons is required for stability. This is because neutrons produce only attractive (nuclear) force amongst them.