The increase in potential energy as two atoms in a diatomic molecule get closer is partly due to the core electrons being forced by the exclusion principle to higher energies. Can you argue why the residual strong force should have a “hard core”.

The strong force has a short range, and within this range, the force is almost constant.

This law describeshow intense the light will be with respect to the distance of the source.

It states thatthe intensity of the light will be inversely proportional to the square of the distance.

The strong force has a short range, and within this range, the force is almost constant.

In contrast, the electromagnetic force follows the inverse square law.

This means there is a limit to how close two protons can get together.If they are too close, the repulsive electromagnetic force is going to be bigger than the strong force, and the two nucleons will separate again.

Since the residual strong force is the sum of the electromagnetic force and the strong force, it will behave the same.

In other words, it has a 'hard core'.