So we started with 10 valence electrons, we used up 8 of those electrons in terms of making bonds.

我们一开始有十个价电子，然后用掉了八个电子来成键。

麻省理工公开课 - 化学原理课程节选

And also I wanted to mention in terms of checking your Lewis structures, regardless of what they are, you should always go back and I had 10, and then count 2, 4, 6, 8, 10, because you always need to make sure you have the same number of valence electrons that you calculated in your actual structure.

我还想提一点关于检查,你的路易斯结构的建议，不管它们是什么，你总是应该回去检查一下,我有十个，然后数一数，二，四，六，八，十个，因为你总是需要确保实际价电子的数量,与你在结构中算出的数量相等。

麻省理工公开课 - 化学原理课程节选