Heavy stable nuclei haveVc2 more neutrons than protons. This is because of the fact that

1. neutrons are heavier than protons

2. electrostatic force between protons is repulsive

3. neutrons decay into protons through beta decay

4. nuclear forces between neutrons are weaker than that between protons

(2) Hint: The stability of the nuclei depends upon the force between the neucleons.
Stable heavy nuclei have more neutrons than protons. This is because the electrostatic force between protons is repulsive, which may reduce stability.