Now when it comes to examining a neutron or proton plot, it's also important to take into account atomic forces. Now recall that the nuclear force holds a nucleus together, and it's the electrostatic force that wants to pull it apart. Here we're going to say that our neutrons are neutral. Subatomic particles of an isotope act as a chemical glue that holds together the nucleus.
Remember, like charges repel one another. If our nucleus was comprised of only protons, positively charged subatomic particles, then we repel each other, breaking the nucleus apart. The neutrons are kind of acting as in-betweens for those protons. They're not going to be in direct contact with each other, so they're not going to be for repulsion. Now here we're going to say these forces being out of balance is another reason radioactive isotopes undergo nuclear decay.
We're trying to get to an equilibrium between the two exact forces, which gets us closer and more into the band of stability. So remember when we're looking at a typical neutral proton plot, we say to the left of our band of stability we have an excess of neutrons or beta decay is more likely to occur. To the right, we have excess protons, which means that electron capture positron emission can occur. Now here we're really focusing on those two sections. We're not looking at the top right corner since that does alpha decay and nuclear fission, things can get a little bit hairy in terms of what can happen.
Now here in the band of stability, the forces are in balance with one another, so we'd say that they are equal to one another. Now, if we have excess neutrons, excess glue. If we have excess neutrons, what does glue help us to do? Helps us to hold things together. So we'd expect our nuclear force to be greater than our electrostatic force overall. And then when we have excess protons, light charges repel each other. So there's going to be a greater tendency for repulsion occurring. So if there's more repulsion, there's a greater need to pull the nucleus apart.
In these instances, we'd say that nuclear force<electrostatic force. So just remember, these atomic forces also play a role in understanding why certain radioisotopes are stable and unstable.