So any time in a molecular orbital diagram you draw in orbitals, you need to draw the corresponding molecular orbitals.

任何时候你在分子轨道图里画轨道，你都要画出相对应的分子轨道。

麻省理工公开课 - 化学原理课程节选

So, in this case, we're just drawing the molecular orbital diagram for the valence electrons, so we have three for each.

所以在这个例子里面，我们只需要画出,价电子的分子轨道图，所以每个有3个电子。

麻省理工公开课 - 化学原理课程节选

I want to do energy level diagrams for molecules.

我要为分子制作能级图。

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OK PROFESSOR: Valence electrons. OK, sometimes you're going to be asked to draw a molecular orbital diagram where you're asked to include all electrons, and sometimes it will specifically say only include valence electrons.

教授：价电子，有时候你画一幅分子轨道图,有时候要求你画出所有的电子，有时候特别要求,只包括价电子。

麻省理工公开课 - 化学原理课程节选

It might not have any electrons in it, but it still exists, so you need to draw these into your molecular orbital diagram.

也许它里面没有电子，但它是存在的，所以你需要在分子轨道图里画出来。

麻省理工公开课 - 化学原理课程节选

And what you can see directly from looking at this energy level diagram, is that the molecule that we have is now more stable in the individual atoms.

你从直接看,能级图中会发现，分子比单个的,原子能量更低。

麻省理工公开课 - 化学原理课程节选

So any time that you're drawing these molecular orbital diagrams you want to keep in mind that the number of electrons that you have in atomic orbitals, you need to add those together and put that many electrons into your molecule.

任何时候当你们画分子轨道图时,你们要记住,原子轨道里的电子数，你要把它们加在一起,并放到分子轨道里去。

麻省理工公开课 - 化学原理课程节选

I want to finish this discussion by including the anti-bonding orbital, and this is a tip for you when you're drawing your molecular orbital diagrams, any time you draw a bonding orbital, there is also an anti-bonding orbital that exists.

我想要以包含反键轨道,来结束这个讨论，告诉你们一个,画分子轨道图的小技巧，任何时候你画一个成键轨道，都会存在一个反键轨道。

麻省理工公开课 - 化学原理课程节选

So this is going to be our molecular orbital diagram.

这就是分子轨道图。

麻省理工公开课 - 化学原理课程节选

Let's draw the molecular diagram for h e 2 now.

让我们画一下He2的分子图。

麻省理工公开课 - 化学原理课程节选

So what I want to point out with this case in beryllium is that you don't have to use all of the electrons to figure out the bond order, and in fact, once you get to molecules 10 that are from atoms with atomic numbers of 8 or 10, you're not going to want to maybe draw out the full molecular orbital diagram.

我要指出的是,在Be这种情况下,你不需要利用,所有的电子来指导键序，实际上，一旦分子中,原子序数到达了8或者，你也许不想画出,整个分子轨道图。

麻省理工公开课 - 化学原理课程节选