Proton Attraction

This is not a trivial question. Basically, the binding energy for a nucleus is called the strong nuclear force. It is mediated by something called gluons.

Even though protons are positively charged, they are in a lower energy state when they are partnered with other protons and neutrons. This is evident by the observation that the nucleus' mass is less than the sum of its parts. The difference in mass for a bound nucleus versus neutrons and protons is exactly equal to the energy that binds them.

Remember E=mc^2? Yup, that is how it works. When you slap loose neutrons and protons together you get a net output of energy from fusion and a subsequent tiny reduction in the mass of the components that make up the nucleus.

In order to split the nucleus you must apply the amount on binding energy back in to pull apart the nucleus and liberate the nucleus into its proton/neutron components. This binding energy is converted back into a tiny amount of mass and the individual protons and neutrons regain their mass.

When a nucleus forms it is in a lower energy state than the sum of its individual components.

You need to explore quantum mechanics to understand the nature of the strong force and how it interacts, which is more than I can write here.

Hello rufus,

The answer to that question may not be understood while we live on this small Planet

The Creator has left us many similar puzzles, which we are not truly able to comprehend.

In saying that, we are expected to use our talents and abilities, to find answers where we may.

I'm mindful of the "Science" we were taught in College, over 50 years ago, and so much has been discovered since, with each new discovery turning earlier discoveries and theories upside-down.

I'm interested to see the progressional answers here....

The strong force was the answer. At the close proximity in the nucleus the strong force overwhelms the electromagnetic forces. Much like in close proximity the electromagnetic forces overwhelm the gravitational forces.