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The reason is because we already have a full valence shell for our hydrogen, it doesn't want any more electrons.
原因是因为我们的氢,已经有一个排满的价壳层了，它不再需要多余的电子了。
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But still, when we're talking about the radial probability distribution, what we actually want to think about is what's the probability of finding the electron in that shell?
但当我们讲到径向概率分布时,我们想做的是考虑，在某一个壳层里,找到电子的概率,就把它想成是蛋壳？
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We'll start up a shell and we'll try it. All right, we'll just get out of what we were doing here.
我们开一个shell然后试试，先退出现在的这个来。
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And so when we get to n equals three that would be m shell by the spectroscopists' notation.
当n等于3的时候,根据光谱学家的标记法，那就是第m层。
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Step three in our Lewis structure rules is to figure out how many electrons we would need in order for every single atom in our molecule to have a full valence shell.
路易斯结构规则的第三步是,找出让分子中每个原子的价壳层,都排满应该需要多少个价电子。
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So the 3 s 1, or any of the other electrons that are in the outer-most shell, those are what we call our valence electrons, and those are where all the excitement happens.
它们是经常发生激发情况的,那也是我们所看到，我们称之为价电子，它们是经常发生激发情况的。
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So if we actually go ahead and multiply it by the volume of our shell, then we end up just with probability, which is kind of a nicer term to be thinking about here.
乘以壳层的体积,我们就得到了概率，在这里从这个角度，理解问题更好一些,如果我们考虑的是。
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So, in order to fill up our shell, what we need is 3 times 8 or 24 electrons.
因此，为了填满所有的壳层，我们需要三乘以八也就是二十四个电子。
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We're saying the probability of from the nucleus in some very thin shell that we describe by d r.
某一非常薄的壳层dr内,一个原子的概率,你想一个壳层时。
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So, basically what we're saying is if we take any shell that's at some distance away from the nucleus, we can think about what the probability is of finding an electron at that radius, and that's the definition we gave to the radial probability distribution.
本质上我们说的就是,如果我们在距离原子核,某处取一个壳层，我们可以考虑在这个半径处,发现电子的概率，这就是我们给出的,径向概率密度的定义。
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That's kind of your shell that we're discussing.
我们讨论的大概就是，这种样子的壳层。
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Let's look at it again. All right it's time to interrupt the world, and we'll just type into the shell.
好，让我们再来看看,好，我们输入shell命令，看结果怎么样。
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So, what we can do to actually get a probability instead of a probability density that we're talking about is to take the wave function squared, which we know is probability density, and multiply it by the volume of that very, very thin spherical shell that we're talking about at distance r.
我们能得到一个概率,而不是概率密度的方法,就是取波函数的平方，也就是概率密度，然后把它乘以一个在ｒ处的,非常非常小的,壳层体积。
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r And what that is the probability of finding an electron in some shell where we define the thickness as d r, some distance, r, from the nucleus.
在某个位置为,厚度为dr的壳层内,找到原子,的概率，我们来考虑下我们这里所说的。
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N so, we've got five electrons here in the valence shell.
是1s2，2s2，2p3，Nitrogen，is，1s2，，2s2，，2p3，因此，有5个价层电子。
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We're getting further away from the nucleus because we're jumping, for example, from the n equals 2 to the n equals 3 shell, or from the n equals 3 to the n equals 4 shell.
我们将会离原子核越来越远,因为我们在跃迁，比如从，n，等于，2，的壳层到n等于，3，的壳层，或者从，n，等于，3，的壳层到n等于，4，的壳层。
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We learn nothing from examining what is going on down here in n equals one shell.
必须仔细检查不然我们学不到什么的,这里n=1的壳。
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shell What I have here is a Python shell, and I'm going to just show you some simple examples of how we start building expressions.
好，这是一个Python的，我会给大家看一些,关于写表达式的简单的例子。
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So there are two electron configurations in the n equals one shell, if we follow according to the selection rules that we spelled out last day.
如果根据上次课,我们阐明的原子光谱选择定则，我们就会知道在n等于1的那一层,有两种电子图像构型。
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So here we're talking about v plus 1, so if we were to write it just for the neutral electron itself, we would find that the electron configuration is argon, that's the filled shell in front of it.
这里我们要分析的是正一价的钒离子，因此，我们先写出中性原子的电子排布，可以发现，其原子实是氩原子的电子排布，这些壳层已经被占满了。
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So when we talk about p orbitals, it's similar to talking about s orbitals, and the difference lies, and now we have a different value for l, so l equals 1 for a p orbital, and we know if we have l equal 1, we can have three different total orbitals that have sub-shell of l equalling 1.
当我们考虑ｐ轨道时，这和ｓ轨道的情形和相似，不同之处在于ｌ的值不一样，对于ｐ轨道，ｌ等于１,我们知道如果ｌ等于１,我们有３个,不同的轨道。
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a perfectly spherical shell dr at some distance, thickness, d r, dr we talk about it as 4 pi r squared d r, so we just multiply that by the probability density.
在某个地方的完美球型壳层,厚度，我们把它叫做4πr平方，我们仅仅是把它,乘以概率密度。
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So we actually only need two electrons to fill up the valence shell of hydrogen, remember that's because all we need to fill up is the 1 s.
我们其实只需要两个电子,就可以将氢的价壳层排满，要记得这是因为我们只需要排满，1，s，轨道。
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And, if we go to n equals two, this would be the l shell.
而当n等于2时，也就是L层。
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And we can generalize to figure out, based on any principle quantum number n, how many orbitals we have of the same energy, n and what we can say is that for any shell n, there are n squared degenerate orbitals.
我们可以总结出来，在，主量子数为n的情况下，同一个能量上，有多少个轨道，我们可以说，对任何壳层，有n平方个简并轨道。
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So if we write the electron configuration you see that this is the electron configuration here, 1s22s22p 1 s 2, 2 s 2, 2 p 6, 3s1 and now we're going into that third shell 3 s 1.
现在我们来到第三层,你们会看到3s1价电子之间的区别，电子构型是，现在我们来到第三层。
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The other main difference that we're really going to get to today is that in multi-electron atoms, orbital energies depend not just on the shell, which is what we saw before, not just on the value of n, but also on the angular momentum quantum l number. So they also depend on the sub-shell or l.
我们今天要讨论的,另一个很重要的区别就是,在多电子原子中，轨道能力不仅仅依赖于，我们以前看到的外层，不仅仅依赖于n的值，而是与角动量量子数也有关系,所以它们也依赖于亚外层或者。
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s But it just turns out that the 4 s is so low in energy that it actually surpasses the 3 d, because we know the 3 d is going to be pretty high in terms of the three shell, and the 4 s is going to be the lowest interms of the 4 shell, and it turns out that we need to fill up the 4 s 4s before we fill in the 3 d.
但是结果是,能量较低,4s是第四层最低的，因为我们知道3d在第三层,是非常高的，4s是第四层,最低的，结果是我们在填充3d之前,需要先填充。
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So what I want to point out when you're kind of looking at these numbers here, what the significance is, look at that huge difference between what the ionization energies are for what we call those valence electrons, -- those outer shell electrons, those are core electrons there.
我在这里想要指出的是,当大家在看这些数字的时候，最重要的是，要看到这些,巨大的差异,看到所谓价电子，即外层电子的电离能与，1，s，轨道，电离能之间的巨大差异。
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