So that thorium-234 that formed when uranium underwent alpha decay?

那么当铀经历 α 衰变时形成的钍 234 呢？

In alpha decays, the sum of the atomic and mass numbers are always equal on either side of the equation.

在 alpha 衰变中，等式两边的原子数和质量数之和始终相等。

First, there’s alpha decay, which is released when an unstable nucleus loses two protons and two neutrons, becoming a different element in the process.

首先是 alpha 衰变，当一个不稳定的原子核失去两个质子和两个中子时，它就会释放出来，在这个过程中变成不同的元素。

This is called alpha decay and the particle that it emits is basically the same as a helium nucleus: two protons and two neutrons.

这称为 α 衰变，它发射的粒子与氦原子核基本相同：两个质子和两个中子。

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。