Scientific Tutor

How does radioactive decay work?

Radioactive decay is part of what we have described so far in this lesson as alpha, beta, or gamma radiation or fission. Radioactive decay is just describing how elements break down into other elements. All of radioactive decay is dictated by one fact; that each element has a favored balance between the protons and neutrons in its nucleus. It is kind of like how each game you play has an optimal number of people that you want to play with. Too many people and the field becomes crowed. Too few and play becomes slow. This balance of protons and neutrons in the nucleus is also not the same for every element. For the lighter elements, the balance seems to be best around 1 proton to 1 neutron. For the heavier elements, the balance seems to be best when you have about 1 proton for every 1.5 neutrons. There are a lot of explanations in science of exactly why this happens but most are fairly complex. The way I tend to think about it is a three-pronged approach.

1) The interaction of a proton with other protons.

2) The interaction of a proton with neutrons.

3) The interaction between a neutron with other neutrons.

You probably have not given it much thought until now, but what happens when you try to put two protons near each other? Well, what happens when two positive charges are next to each other? They repel from each other. So the protons in the nucleus are trying to get away form the other protons in the nucleus. Then why do the protons all remain in the nucleus? I like to think of the neutrons like a glue material. The purpose of neutrons is to help glue together protons so they don’t go flying out of the nucleus. However, neutrons also interact with neutrons to repel each other. So we have 3 basic forces competing here.

1) Will push apart the nucleus.

2) Will hold together the nucleus.

3) Will push apart the nucleus.

A stable nucleus is one that will keep these 3 forces in stable balance. A stable nucleus will also hang around for a long period of time on average. On the other hand, and unstable nucleus will not strike a balance between the 3 forces and therefore only hang around a short time on average. Most people will tell you that the statements I have made above are untrue but it is my simple way of explaining something that is very complex and is still not full understood.