For example, if the parent nucleus is radium, it would decay into radon and emit a single alpha particle.

例如，如果母核是镭，它会衰变为氡并发射单个 α 粒子。

This decay occurs because the parent nucleus is too large, and the strong force is no longer sufficient to hold all the nucleons together.

发生这种衰变是因为母核太大，强力不再足以将所有核子聚集在一起。

So the products of this reaction always have less total mass – as measured in unified atomic mass units – than the parent nucleus has.

因此，该反应的产物总质量（以统一原子质量单位衡量）总是小于母核。

In alpha decay, there’s a parent nucleus – which is the original, unstable nucleus – and it decays into a daughter nucleus and an alpha particle, which is actually just the nucleus of a Helium atom.

在 alpha 衰变中，有一个母核——它是原始的、不稳定的核——它衰变成一个子核和一个 alpha 粒子，它实际上只是一个氦原子的核。