Step three in our Lewis structure rules is to figure out how many electrons we would need in order for every single atom in our molecule to have a full valence shell.

路易斯结构规则的第三步是,找出让分子中每个原子的价壳层,都排满应该需要多少个价电子。

麻省理工公开课 - 化学原理课程节选

And if we go on to step three where we figure out how many we would need for full octets, it's just going to be 2 times 8, so we have 16.

而如果我们继续到第三步,判断一下填满所有“八隅体“需要多少个价电子，结果应该就是二乘以八，也就是十六个。

麻省理工公开课 - 化学原理课程节选

So we have 18 electrons, and the next thing that we need to figure out is how many bonding electrons we have.

那么我们有十八个电子，下一步要做的是判断,我们有多少个成键电子。

麻省理工公开课 - 化学原理课程节选

Our step three is to figure out how many bonding electrons that we need, or excuse me, how many total electrons that we need to fill up our octets, so that's just going to be 4 times 8, which is 32.

我们的第三步是判断,我们需要多少个成键电子，不好意思，是我们总共需要多少个电子,才能填满所有“八隅体“,那么这就应该是四乘上八，也就是三十二。

麻省理工公开课 - 化学原理课程节选

So this means we can actually calculate this for any molecule that we've drawn the Lewis structure for, because we actually do need to draw the Lewis structure before we know, for example, how many of each of these we have, or at least go through the rules.

这意味着我们可以将原来画过,路易斯结构的分子的形式电荷计算出来，因为我们其实在画出,路易斯结构之后才能知道，比如，这些量的值是多少，或者至少我们需要经过前面的那些步骤。

麻省理工公开课 - 化学原理课程节选

How many electrons do we need to have full valence shells?

要把价层排满需要多少个电子？

麻省理工公开课 - 化学原理课程节选

How many do we need to get full valence shells everywhere?

要得到全部是满壳层需要多少个？

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We know we need to divide by 266, 266 but what we need you to help us with is to figure out this top number here and see how many particles are going to backscatter. So if the TAs can come up and quickly hand out 1 particle to everyone.

知道背散射的概率就可以了，我们知道要除以,但还需要你们来搞清楚,分子上的数是多少，有多少个发生背散射的粒子,助教们请过来,把这些球分给同学们。

麻省理工公开课 - 化学原理课程节选