Radioactive decay Radioactive decay a the spontaneous process through which an unstable atomic nucleus breaks into smaller, more stable fragments. Have you ever wondered exactly why some nuclei decay, while others don't? It's basically a matter of thermodynamics. Every atom seeks to be as stable as possible. In t Radioactive decay occurs because an atom's atomic nucleus isn't stable, due to a mismatch in the numbers of protons and neutrons[/caption] he case of radioactive decay, instability occurs when there is an imbalance in the number of protons and neutrons in the atomic nucleus. Basically, there is too much energy inside the nucleus to hold all the nucleons together. The status of the electrons of an atom doesn't matter for decay, although they, too, have their own way of finding stability. If the nucleus of an atom is unstable, eventually it will break apart to lose at least some of the particles that make it unstable. The original nucleus i
