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。

麻省理工公开课 - 化学原理课程节选

It's a sigma bond, - and it's going to be -- N2sp3 no. OK, it's going to be nitrogen 2 s p 3, because it's a nitrogen atom, 1s and then hydrogen 1 s.

它是sigma键，它是-,不，OK，它是，因为这是个氮原子，然后是氢。

麻省理工公开课 - 化学原理课程节选