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But I'm sure you can easily see how these styrofoam balls could, in fact, be a mono layer of gold nuclei.
这个实验怎么工作的,我们先来做些计算，但我相信你们都已经。
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If we think about the size of a typical cell - excuse me, now I'm getting confused about nuclei.
它大约是10的,负十四次方米，如果我们考虑。
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And just to give you a sense, if you do a cross-cut of this, you cannot show it from this angle, but it should really be sort of a dumbbell shape with the nodal plane in between the two nuclei.
告诉你们这些就是给你们点概念，假如你们把他横切切开，不能从角度上展示，但它还是会保留几分哑铃的形态,以及在两核之间的节面。
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So you can see that this is non-bonding, this is even worse than non-bonding, it's anti-bonding, because we're actually getting rid of electron density between the two nuclei.
所以你可以看到这是不成键的，它甚至比不成键还糟糕，它是反键，因为我们实际上是去掉了,两个原子核之间的电子。
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So again, this is an anti-bonding orbital, and what you see is that there is now less electron density between the two nuclei than there was when you had non-bonding.
同样的，这是反键轨道，你们看到当你有反键轨道的时候,两个原子核中间的电子密度更小了。
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The reason is because the predominant force at this point is going to be the attraction that's being felt between the nuclei and the electrons in each of the atoms.
这是因为这时候最主要的力,是吸引力，它来自于,其中一个原子的电子与另外一个原子的原子核之间。
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So, here we have the area of the nuclei we'll figure out adding those all together versus the space of all of the atoms put together.
有原子核的面积,通过除以所有原子的,总面积。
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Right, this makes a lot of sense because if the entire atom was made up of nuclei, then we would have 100% probability of hitting one of these nuclei and having things bounce back.
因为如果整个原子,都是原子核，那我们就有100%概率,撞到一个原子核并被弹回来,所以如果我们。
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And we can also talk about the bond length, so we might be interested in what the bond length is, what the distance between these two nuclei are.
另外一点就是键长，我们对键的长度也感兴趣，也就是两个原子核之间的距离。
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What we're going to do in forming a molecule is just bring these two orbitals close together such that now we have their nucleus, the two nuclei, at a distance apart that's equal to the bond length.
我们在形成一个分子时要做的就是,把这两个轨道放到一起,这样我们有他们的原子核，两个原子核，它们之间的距离为键长。
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And so it has what? In contrast to the sigma, it has a nodal plane containing both nuclei.
这是什么，和sigma相反，它是包覆在核上的平面电子云，有一个界面。
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And we know that it's electron density between the nuclei that holds two atoms together in a bond.
我们知道是两个原子核之间的,电子密度保持两个原子在一起成键的。
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So, it'll be considered a backscatter event if your ping-pong ball hits one of the nuclei.
什么情况是背散射,如果你们的乒乓球。
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When we were talking about constructive interference, we had more electron density in between the 2 nuclei.
当我们讨论相长干涉的时候，在两个原子核之间有更多的电子密度。
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And the real killer is if we get too close we're even going to have nuclear-nuclear repulsion between the nuclei of the two atoms.
而更致命的是，如果我们靠得太近,我们甚至会有,两个原子核之间的排斥力。
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Alpha particles are these helium nuclei, and they are the result of radioactive decay.
阿尔法粒子是氦核，它们是放射性衰变的产物。
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They will smear to give you something like this where here are the two nuclei.
他们会形成这样的结构,这是两个核。
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So that is the bond axis it's just the axis between the two nuclei.
这就是键轴,它就是两个原子核之间的轴。
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For, as Rutherford has shown the assumption of the existence of nuclei, as those in question seems to be necessary in order to account for the results of the experiments on large angle scattering of the alpha rays.
因此卢瑟福,提出了原子核存在的假设，这些关于问题的假设对于,解释阿尔法粒子的,大角度散射是有必要的。
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So, we're going to start with talking about bonding, and any time we have a chemical bond, basically what we're talking about is having two atoms where the arrangement of their nuclei and their electrons are such that the bonded atoms results in a lower energythan for the separate atoms.
那么，下面我们将从成键开始讲起，无论什么时候我们有一个化学键，基本上我们所讨论的,都是如何安排两个原子的原子核的位置,与电子的位置使得成键的两个原子,最终比分开时的能量更低。
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And what we end up forming is a molecular orbital, because as we bring these two atomic orbitals close together, the part between them, that wave function, constructively interferes such that in our molecular orbital, we actually have a lot of wave function in between the two nuclei.
最后我们得到了分子轨道，因为当我们把这两个原子轨道放在一起的时候，它们之间的部分，波函数，相干相加，所以在分子轨道里，我们在两个原子核之间有很多波函数。
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that's one way to think about it, and there's also another way, and this is the way that your book presents it. If you, in fact, have two of the same atom right next to each other, let's say you have a crystal, or let's say you're talking about a metal, what you can do is just look at the distance between the two nuclei, and split that in 1/2, and take the atomic radius that way.
这只是一种定义的思路，另外还有其它方法，也就是你们课本上的方法，如果你，事实上，有两个相同的原子彼此靠在一起，比如说你有一个晶体，或者说你讨论的是一个金属，你所要做的就是,看看这两个原子核之间的距离，然后将距离除以二，就得到了这个原子的半径。
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So this is the 1 s star, sigma 1 s star orbital, and what you have in the center here is a node, right in the center between the two nuclei.
这是1s星，sigma1s星轨道，中间这个是节点，它在两个原子核中间。
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When we're talking about r for internuclear distance, we're talking about the distance between two different nuclei in a bond, in a covalent bond.
当我们说，r，代表的是核间距的时候，我们讨论的是一个距离,在一个键--一个共价键的两端的原子核之间的距离。
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So, not only did Professor Sayer, who's in the Chemistry Department who put together this contraption for all of you, not only did she magnify the size of these gold nuclei, but she actually had to smoosh all of these atoms closer together then they normally would be.
化学系的Sayer教授把这些玩意放到一起，她不仅把金原子核的,尺寸放大了,还把原子核的间距压缩了,事实上，如果原子核的尺寸有这么大,我们需要另一个大教室，放这个原子核。
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So, the number of nuclei, 119 if we were to sit and count these as well, is 119. So, we'll multiply that by just pi, r squared, to get that cross-section, and divide all of that by 1 . 39 meters squared.
如果你们数的话，原子核的数是，我们用它乘以πr的平方，得到横截面积，除以1。39平方米。
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