So in terms of nitrogen that starts off with a valence number of 5, again we have 2 lone pair electrons in the nitrogen, and again, we have 6 electrons that are shared.

对于氮来说,我们应该从五个价电子开始，同样，氮也有两个孤对电子，共用电子的个数也一样，是六个。

麻省理工公开课 - 化学原理课程节选

Well, we're talking about a pretty high number here, so to make counting easier, we'll just say 10 lone pairs, because 20 lone pair electrons is the same thing as 10 lone pairs.

好吧，我们这里讨论的是一个挺大的数，为了数起来更容易，我们就说有十对孤对电子，因为二十个跟十对是一个意思。

麻省理工公开课 - 化学原理课程节选

If it isn't, then I'm going to go back around the loop, and notice what happens. If I get all the way around the loop, that is, all the way through that FOR loop and I never find a path that takes me through here, then the last thing I'm going to do is return a pair or a tuple with a special simple number none twice.

如果没有,我会回到循环看看发生了什么,如果我运行了整个循环,也就是整个for循环,我仍没有找到符合条件的路径,那么我最后做的事情就是返回一对,或者一个数组的两次none值。

麻省理工公开课 - 计算机科学及编程导论课程节选

So, if we want to figure out the formal charge on the carbon, we need to take the number of valence electrons, so that's 4. We need to subtract the lone pair, what number is that? It's 2.

如果我们想算出碳原子的形式电荷，我们需要将价电子的个数，也就是四，减去孤对电子的个数，它是多少？是二。

麻省理工公开课 - 化学原理课程节选

And if we talk about chlorine, and both of the chlorines are the same in this case, we start with a valence number of 7 for chlorine, and then we subtract 6, because it had 6 lone pair electrons around each of the chlorine atoms.

而如果我们讨论氯的话，在这个例子中两个氯的情况都是一样的，从七个价电子开始，然后减去六，因为每个氯原子周围,都有六个孤对电子。

麻省理工公开课 - 化学原理课程节选