The reason is because we already have a full valence shell for our hydrogen, it doesn't want any more electrons.

原因是因为我们的氢,已经有一个排满的价壳层了，它不再需要多余的电子了。

麻省理工公开课 - 化学原理课程节选

So we actually only need two electrons to fill up the valence shell of hydrogen, remember that's because all we need to fill up is the 1 s.

我们其实只需要两个电子,就可以将氢的价壳层排满，要记得这是因为我们只需要排满，1，s，轨道。

麻省理工公开课 - 化学原理课程节选