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So what we're going to see is less shielding, which means that it will actually feel a higher z effective.
那么我们将会看到更少的屏蔽，这意味着将会感受到更大的有效核电量。
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And let's say our second electron now is really far away, such that it's actually not going to shield any of the nuclear charge at all from that first electron.
距离原子核非常非常近,我们说第二个电子处于非常远的位置,这样它不会对第一个电子,感受到的来自原子核的电荷量有任何屏蔽作用,我们最后要说的是。
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There's one more piece that we'd like to get out of that, and that is-- you may have been wondering, what's with the funky stuttering here of three double-quotes in a row. All right? And that is a specification.
但是你没有屏蔽这个函数的使用细节,在这里我们还想再讲一讲,那就是--你可能正在想,这里连续3个奇怪双引号,是干什么用的。
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But now it's going to make more sense because in that case we were just talking about single electron atoms, and now we're talking about a case where we actually can see shielding.
但是现在能讲得通了,因为在那个情况中我们仅仅是现在我们讨论的是,讨论单电子原子，看到屏蔽的案例,我们能看到屏蔽。
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All right. So now that we have a general idea of what we're talking about with shielding, we can now go back and think about why it is that the orbitals are ordered in the order that they are.
现在我们对于谈论的屏蔽,有一个整体观点了，我们现在可以回过头来考虑,为什么轨道是按照,那种规则排列的。
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But shielding is a good way to think about it, and actually, that's what we'll use in this class to sort of visualize what's happening when we have many electrons in an atom and they're shielding each other.
实际上，它也是我们将在课堂上用于,分类形象化的当我们有,很多电子在原子中,它们互相屏蔽时会发生些什么,屏蔽是被使用的名词。
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Not only are we taking away an electron here, but we're also going to decrease shielding, so the electrons that are already in there are going to feel a higher z effective and will be pulling and the atom will be getting smaller.
这不只是因为我们拿走了一个电子，还因为我们这样做会减小屏蔽效应，这样留下的电子,将会感受到更大的有效核电量,也就会感受到更强的吸引力，使得原子变得更小。
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Well, the reason, the way that we can check it is just to see if it's in between our two extreme 1 cases. We know that it has to be more than 1, because even if we had total shielding, 1 we would at least feel is the effective of 1.
好的我们可以检查它的原因和方式是观察,它是否在我们的两种极端案例之间,我们知道它必须大于，因为即使如果我们有完全的屏蔽，我们最小感到的有效值是。
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And the reason that they're the least sheilded is because they can get closest to the nucleus, so we can think of them as not getting blocked by a bunch of other electron, because there's some probability that they can actually work their way all the way in to the nucleus.
它们最不容易被屏蔽的原因,是因为他们可以更加接近原子，所以我们可以认为它们,最不容易被其它原子阻挡住，因为它们有一定的概率,离原子核非常近。
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It turns out, and we're going to get the idea of shielding, so it's not going to actually +18 feel that full plus 18, but it'll feel a whole lot more than it will just feel in terms of a hydrogen atom where we only have a nuclear charge of one.
结果是我们会有,屏蔽的想法,所以它不会是完整的，但是它会比原子核电荷量,吸引力要大很多,只有1的氢原子的。
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So let's take two cases of shielding if we're talking about, for example, the helium, a helium nucleus or a helium atom.
所以我们来对屏蔽举两个例子,如果我们在讨论氦，举例来说一个氦原子核或者氦原子。
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Of course, if we saw no shielding at all what we would end up with 3 is a z effective of 3.
当然如果我们说没有任何屏蔽,我们最后得到的,有效电荷量是。
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So, what we can do is figure out what we would expect the binding energy of that electron to be in the case of this total shielding.
完全屏蔽的案例中,期望的电子结合,能再次记住,结合能物理上来说是。
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9 or . 8 7 are possible, they actually aren't possible because even if we saw a total shielding, 1 the minimum z effective we would see is 1.
。39和0。87是可能的，实际上它们是不可能的因为即使,我们看到了一个完全的屏蔽，最小的有效电荷是。
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They're less shielded because they're closer to the nucleus, they feel a greater z effective.
它们受到少的屏蔽,因为它们离原子核更近，它们感觉到一个更大的有效电荷量。
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And shielding is a little bit of a misnomer because it's not actually that's the electron's blocking the charge from another electron, it's more like you're canceling out a positive attractive force with a negative repulsive force.
屏蔽有一点点用词不当,因为它事实上不是,电子阻挡了来自另一个电子的电荷,它更像你在用一个负排斥力，抵消一个正吸引力,但是屏蔽是考虑这个问题,的很好的方式。
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There are fewer electrons around to s hield some of that nuclear charge.
即周围屏蔽原子核电量的,电子更少。
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And this is absolutely confirming that what is happening is what we would expect to happen, because we would expect the case of reality is that, in fact, some shielding is going on, but it's not going to be total shielding, but at the same time it's not going to be no shielding at all.
因为我们期望看到的真实情况是,事实上,一些屏蔽发生了,但它不是完全的屏蔽，但与此同时它也不是，一点屏蔽也没有,如果我们从实验中得到电离能是多少。
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So, shielding happens when you have more than one electron in an atom, and the reason that it's happening is because you're actually canceling out some of that positive charge from the nucleus or that attractive force with a repulsive force between two electrons.
所以当你们在原子中有多于一个电子,屏蔽就会发生，它之所以会发生的原因是,你们实际上抵消了,一些来自原子核的正电荷,或者来自吸引力,在两个电子之间。
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This is what we call total shielding.
我们称之为完全屏蔽。
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And if we do that calculation, what we find out is that the binding energy, in this case where we have no shielding, 72× is negative 8 . 7 2 times 10 to So, let's compare what we've just seen as our two extremes.
我们会发现结合，能在这个情况中，没有屏蔽，等于-8。,所以我们来对比一下,我们在两个极端的案例中看到了什么。
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A kind of consequence of this is if we're thinking about a multi-electron atom, which we'll get to in a minute where electrons can shield each other from the pull of the nucleus, we're going to say that the electrons in the s orbitals are actually the least shielded.
这样的一个后果就是,如果我们考虑一个多电子原子，我们等会就会讨论到它,电子会互相,屏蔽原子核的吸引，我们说ｓ轨道电子,更不容易被屏蔽。
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And for the s electron, since it can get closer, what we're going to see is that s electrons are actually less shielded than the corresponding p electrons.
对于s电子，因为它可以离得更近，我们可以看到s电子事实上,相对于p电子受到,更少的屏蔽。
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And it turns out that if we're talking about a 2 s orbital in an ion, that means it doesn't have as many electrons in it, so what we're going to see is less shielding.
结果是当我们讨论,一个离子中的，2，s，轨道的时候，这意味着里面没有多的电子，那么电子的屏蔽效应会更小。
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In an extreme case b, we had a z effective of 2, so essentially what we had was no shielding at all.
我们有效的z是，所以本质上我们完全没有屏蔽。
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And the point that I also want to make is the way that they differ, z effective actually differs from the total charge in the nucleus due to an idea called shielding.
我也想指出的一点是它们不同的方式,有效的z事实上不同于原子核的，总电荷量,因为屏蔽效应。
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So this is not even thinking about the other electron shielding, just if we think of the fact, all we need to think about is that the effect of going to a further away n n as we go down the table.
到现在我们甚至还没有考虑,其它电子的屏蔽效果，即使我们要考虑这个因素，我们需要考虑也就是,沿着周期表的某一列往下走，距离会逐渐变远,将起最重要的作用，actually，dominates,这一结果所产生的影响。
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We know that it has to be equal to less than 2, because even if we had absolutely no shielding at 2 all, the highest z effective we could have is 2, so it makes perfect sense that we have a z effective that falls somewhere in the middle of those two.
我们知道它必须小于，因为即使完全没有一点屏蔽,最高的有效的z是，所以我们得到的有效电荷量处于,两者之间就非常讲得通了,让我们来看看另一个例子。
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But we haven't yet addressed why, for example, a 2 s orbital islower in energy than the 2 p orbital, or why, for example, a 3 s orbital is lower in energy than a 3 p, which in turn is lower than a 3 d orbital.
但是我们还没有强调为什么，举个例子一个2s轨道能量低于2p轨道,或者为什么，举例来说它依次低于3d轨道,屏蔽一个3s轨道的能量小于3p轨道。
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