How are atoms with less neutrons than protons radioactive?



Helium and Hydrogen aside, I know if an atom has less neutrons than protons, it’s considered unstable, and is therefore radioactive. But don’t radioactive atoms emit neutrons, which would only make them more unstable? I read some comment on another site that said the protons are the ones that are emitted, but wouldn’t that change the element itself?

In: Chemistry

When an element emits nuclear radiation, it does in fact break down into a different, smaller element or elements.

This is the very basis of radioactive decay and half life.

Half life means in a certain amount of time, half of the elements would have decayed into something else, and in the process, releasing radiation as it decays.

Physicist here. It has to do with the strong nuclear force. That’s the force that holds atomic nuclei together.
Typically, protons repel one another through the electromagnetic force. But when they get close together, a property known as “color charge” causes an attraction and holds them together.
Even though the strong force is powerful, there still needs to be something else in the nucleus to act as a “buffer.” It has to do with the energy of the nucleus. The configuration of the nucleus has an energy sweet-spot. Too much or too little energy and the nucleus won’t survive. Basically, if there are too many protons or neutrons, the nucleus will fall apart.

Nuclei have energy states like electrons. If the energy is too much, it will break apart.

If the atom has too few neutrons, then it can decay via positron emission. In that case a positron (a.k.a. an anti-electron) is emitted from the nucleus and carries away the positive charge of the proton. The proton then becomes a neutron. Then the atom is definitely a different element.

I tried to make it as straightforward and brief as possible. There is still a lot more going on there, but that’s the gist of it.