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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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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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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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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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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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