Question

Why is the number of neutrons greater than the number of protons in stable nuclei having A greater than about 40, and why is this effect more pronounced for the heaviest nuclei?

a) Neutrons contribute more to stability in heavy nuclei.

b) Protons contribute more to stability in heavy nuclei.

c) Neutrons are repelled by protons, requiring more in heavy nuclei.

d) Neutrons are attracted to protons, requiring more in heavy nuclei.

Answer 1

Heavy nuclei require more neutrons to achieve stability and balance the repulsive forces between protons. This effect is more pronounced in the heaviest nuclei due to the increasing strength of the long-range electrostatic force between protons.

Step-by-step explanation:

In stable nuclei with an atomic number (A) greater than about 40, the number of neutrons is greater than the number of protons. This is because heavy nuclei require more neutrons to achieve stability and balance the repulsive forces between protons.

The effect of having more neutrons compared to protons is more pronounced in the heaviest nuclei. This is because the long-range electrostatic (Coulomb) force between protons in the nucleus becomes stronger as the atomic number increases, and having more neutrons helps to reduce the Coulomb repulsion between protons and keep them farther apart.