Chapter 2: Nuclear Structure and Decay

In the previous chapter, we reviewed the structure of the atom and the nucleus. The atom has a size of approximately 10−10 m (1 Å) and a very small nucleus, measuring 2–10 fm (1 fm = 10−15 m). It may be surprising that the atomic nucleus can be stable, given that the protons are in such close proximity to each other. (Remember that the repulsive force between two particles is described by Coulomb’s Law and scales as 1/r2 where r is the distance between the particles. A small distance results in large forces.) There is, however, a balancing force, the strong force described by quantum mechanics that holds the nucleus together. It is beyond the scope of this series to discuss that force, but the reader may refer to Podgorsak (2016) for more information.