What is alpha decay?
Simply put, it is a
So the bigger question is why does an atom emit an
Think about the kinds of atoms that emit
That balance between protons and neutrons is critical. Too many neutrons and one of the neutrons will balance out the ratio by turning into a proton and emitting a beta particle. Too many protons, and you get alpha decay, where the atom loses two protons and two neutrons, decreasing the ratio of protons to neutrons and making the atom more stable.
Now combine an alpha particle and two beta decays and you end up with the same nucleus you started with, but it is 4 amu lighter.
Kind of cool.