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And you would find that the bond energy of the heteronuclear molecule was nowhere on the average of the two.
你将发现,电子相同的分子的总能量,并不是平分的。
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And you can go ahead and tell me what you think the bond order is going to be for this molecule.
你们告诉我你觉得,这个分子的键序应该是怎样的。
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We only have the one bond so the actual HF molecule is polar, it has a net dipole.
但HF中只有一根键,所以分子也是极性的而甲烷中有一个网状偶极。
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It's going to be a stronger bond because it's more stabilized when it when it comes together as a molecule.
这将是一个更强的键，因为它会变得更加稳定,在形成分子之后。
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Whereas in molecular orbital theory, what I'm telling you is instead we understand that the electrons are spread all over the molecule, they're not just associated with a single atom or a single bond.
而在分子轨道理论里，我要告诉你们的时,我们任为电子分布在整个分子中,它们不仅仅是和,一个原子或者一个键有关。
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It's also important, once we start talking about molecules, to have a way to represent them, and also to be able to look at a shorthand notation for a certain molecule and understand what the bond is.
还有很重要一点是，一旦我们开始讨论分子，我们需要有一种表示它们的方法，而且能够从中看出,某些分子的简化符号，并得知键的类型。
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We're already using it up in this pi bond here, so that means we're limited to only two other spots on the molecule, so we have three.
我们已经把它用到这个π键里去了，所以这意味着,我们在分子里只剩下两个位置，所以一共是三个。
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If we know that this is it the dissociation energy for a hydrogen atom, we can also say the bond strength for hydrogen molecule 424 is 424.
如果我们知道了这是一个氢分子的离解能,那么我们也可以说氢分子的键的强度,就是。
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So really, you can not ever rotate a double bond, it makes your molecule very rigid.
实际上，你不能转动一个双键，它使得你的分子很坚固。
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When we have just a single bond in them molecule, you have all the free rotation you want, you can just spin it around, there's nothing keeping it in place.
当我们在分子力只有一个单键时，你可以随意旋转，你可以让它转起来，没有什么东西能固定住它。
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So, what this lets us do now is directly compare, for example, the strength of a bond in terms of a hydrogen atom and hydrogen molecule, compared to any kind of molecule that we want to graph on top of it.
因此，这让我们现在可以做到直接进行比较，比如，将一个氢原子，和一个氢分子的键的强度，与任何其它类型的分子进行比较,我们只需要把它的曲线也画在这幅图上。
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So, we see is when we use the octet rule to look at fluorine molecule, we're combining two fluorine atoms, and what we end up with is an f f molecule where they're sharing two electrons, so making that covalent bond.
那么，我们看到把八隅体规则用到氟分子上,就是把两个氟原子组合起来，最终得到的氟分子中两个原子,共用一对电子，这就构成了共价键。
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So, in talking about covalent bonds, we should be able to still apply a more general definition of a chemical bond, which should tell us that the h 2 molecule is going to be lower in energy than if we looked at 2 separate hydrogen atom molecules.
那么，既然提到了共价键，我们应该还可以,给化学键下一个更普遍的定义,那就是告诉我们氢分子能量应该更低,与两个分开的氢的单原子分子相比。
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So, if we talk about dissociating h 2, we're going from the h 2 molecule, and breaking this bond right in half, so we now have two individual hydrogen atoms here.
那么，如果我们讨论的是离解氢分子，我们将从氢分子开始，使这个键断裂，一分为二，那么就得到了两个分开的氢原子。
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So, let's change our graph where we now have this zero point set as the two individuals hydrogen atoms, and then we see that our h 2 molecule is at the negative of the dissociation energy, or the negative what that bond strength is.
那么让我们把曲线图中的零点能改到,两个分离的氢原子处，那我们就会看到,氢分子就是负的离解能，或者负的键的强度。
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If we have the molecule ethane, then what we're going to have first is our sigma bond that we described between the two carbons.
如果我们有乙烷分子，那我们首先有,碳碳之间的sigma键。
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This is incredibly important because if you picture having a double bond in a very large molecule, you could have all sorts of other atoms off this way and all sorts of other atoms off this way, and you can picture the shape would be very different if you have one confirmation versus another confirmation.
这是十分重要的,因为如果你想象在一个大分子里有一个双键，你可以在这里有各种各样的其它原子,在这里也有各种各样的其它原子，你可以想象一个构型,和另外一个构型之间的形状差别是非常大的。
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N 2 So any chemist should be able to just look at n 2 and know that it's a triple bond, but that's not something that we've learned how did to do yet, so let's go ahead and start a new topic that's going to allow us to have some sort of sense of what the valence electron configuration, which includes whether something's a single or double or a triple bond can be figured out for any given molecule.
任何一个化学家都应该能够仅仅通过看到2,就知道它有一个三键,但是我们还没学习如何做到这点，因此下面我们就开始进入一个新的主题,它将使我们能够有一定的认识,对于价电子的排布情况，包括可以对任何一个给定分子中的键是单键双键,还是三键作出判断。
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So if we do this and we form the molecule ammonia, let's switch to a clicker question, and have you tell me what the bond angle - is going to be in ammonia -- HNH Actually, let me draw it on the board as you look -- actually, can you put the class notes on, since you don't actually have your notes to refer to.
如果这样做的话，我们就可以形成氨分子，让我们来做一个课堂练习,你们告诉我氨分子中的键角是多少-,键角，the，h，n，h，bond，angle。,实际上让我在黑板上画出它来，这样你们可以看到实际上-,你能把课堂讲义放出来吗，因为你们没有讲义可以参考。
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