>>10853762>So alpha decay is always a helium nucleus that gets ejected, why is that?Kind of a definition, you can get spontaneous fissions where nuclei break up into much larger fragments. alphas are always He-4
>why is it 2 neutrons and 2 protons? Why not 1 of each, or 3?when it decays like that, you have to remember it is going to the most energetically favorable state (ie low energy). The Helium nucleus (He 4) is very tightly bound (look at tables of binding energy / nucleon), it is quite high. You should look at the nuclear shell model to learn why the 2 + 2 is tightly bound, I cant do it justice here. It fills its shell, and the fact its even-even satisfies certain symmetries
>Does this also mean that there is no possible isotope of helium or hydrogen that could alpha decay? Thats right, you wouldnt have enough protons. You can have Be 8 breakup into 2 alphas, which maybe you can call alpha decay, it will tunnel the same QM formalism
