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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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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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Alfred North Whitehead Alfred North Whitehead,the philosopher: "The careful shielding of a university from the activities of the world around us is the best way to chill interest and to defeat progress.
哲学家：,“大学小心翼翼地将我们,与外界活动隔开,这样最容易打击学习兴趣，阻碍学习进步。
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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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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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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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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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So again, when we check these, what we want to see is that our z effective falls in between the two extreme cases that we could envision for shielding.
所以当我们再一次检查这些时，我们想看到的是,有效电荷量处于两种极端案例中,这两种极端案例。
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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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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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So if we have total +2 and complete shielding -1 where that can actually negate a full positive charge, because remember our nucleus is plus 2, +1 one of the electrons is minus 1, so if it totally blocks it, all we would have left from the nucleus is an effective charge of plus 1.
抵消一个完全的正电荷,因为记住我们的原子核是,其中一个电子是,所以如果它完全挡住了它，我们从原子核中留下的，全部有效电荷就是，所以，在我们的第一个例子中,我们的第一种极端情况。
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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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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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Shielding is the term that's used, it brings up a certain image in our mind, and even though that's not precisely what's going on, it's a very good way to visualize what we're trying to think about here.
它带给我们一个确定的画面，虽然那不够精确，但当我们尝试去考虑它的时候,它确实是一种很好,的形象化的方式。
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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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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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So let's think about shielding in trying to answer why, in fact, it's those s orbitals that are the lowest in energy.
所以我们来考虑一下,尝试回答为什么，事实上s轨道,是能量最低的轨道。
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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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