This should make a lot of sense, because we know that a hydrogen has 1 s as it's outer-most or valence orbital, so it can be filled up just with two 1 s electrons.

这也是很合理的，因为我们,知道氢只有，1，s，轨道,这就是它最外层的轨道或者说价轨道，因此只要两个，1，s，电子就可以将它填满。

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