Question

What is the strong nuclear force of an atom?

Answer 1

The strong nuclear force holds protons and neutrons together in the nucleus.

Explanation:

The nucleus of an atom shouldn't really stick together, because protons and protons have the same charge so repel each other. It's like putting two North ends of a magnet together - it doesn't work.

But it does, because of the strong force, so-called because it's strong. It holds the two like-ends of the magnet together, and so keeps the whole atom from falling apart. The boson (force particle) of the strong force is called a gluon, because it is basically a glue.

When the nucleus is unbalanced, when it has too many protons or too many neutrons, the strong force isn't quite strong enough, and so the nucleus loses protons and neutrons (`alpha`-decay) or a neutron turns into a proton (`beta`-decay). The strong force being out of balance causes radioactivity.