So would you expect, therefore, as we go across a row for the atomic radius, to increase or to decrease? Good. OK, yes.

那么大家觉得，原子半径沿着某一行向右走，是会增大还是会减小呢？很好，不错，是的。

麻省理工公开课 - 化学原理课程节选

So we haven't gotten to molecules yet, we're just talking about single atoms or single ions, but what's nice is just talking about this very straightforward principle of atomic radius.

我们还没有开始讲分子，我们仍然只是在讨论单个原子或离子，但它的好处在于可以讨论,这个关于原子半径的非常简单直接的原理。

麻省理工公开课 - 化学原理课程节选

Here is atomic radius versus atomic number.

这是原子半径和原子序数。

麻省理工公开课 - 固态化学导论课程节选

So as we go down we're now adding electrons to further and further away shells, so what we're going to see is that the atomic radius is going to increase as we're going down the periodic table.

当我们向下走时,我们会将电子加在越来越远的壳层上，因此我们将看到原子半径,将随我们沿周期表向下走而增大。

麻省理工公开课 - 化学原理课程节选

So, keep that in mind when we're talking about atomic radius, I'm not suddenly changing my story and saying, yes, we do have a distinct radius.

因此，当我们讨论原子半径的时候要时刻记住这一点，我并不是在突然改变自己的说法，说是的，我们的确有一个准确的半径。

麻省理工公开课 - 化学原理课程节选

And first, on your lecture notes, I start with atomic radius.

首先，在大家的讲义上，我是从原子半径开始的。

麻省理工公开课 - 化学原理课程节选

You just need to remember what's happening to z effective, which really tells us what's happening with all the trends, and once you know z effective, you can figure out, for example, what direction the atomic radius should be going into.

你只需要记住有效核电量的规律，实际上它会告诉我们所有的规律，只要你知道了有效核电量的规律，你就可以判断，比如，原子半径会向着哪个方向发展。

麻省理工公开课 - 化学原理课程节选

And what we've been talking about with all of these properties are, of course, how can we figure out what that is for a certain atom by looking at the periodic table, so we want to think about the periodic trend for atomic radius.

对于我们讲过的这些性质，我们所讨论的一直都是,当然是，我们如何能够判断某一个原子的这些性质,通过观察周期表，因此我们需要思考一下原子半径的周期性规律。

麻省理工公开课 - 化学原理课程节选

And immediately it should probably come into your head that we don't actually have an atomic radius that we can talk about, right?

一提到这点你就应该立刻想到,我们并没有一个真正的原子半径,可以讨论，对吗？

麻省理工公开课 - 化学原理课程节选

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。

麻省理工公开课 - 化学原理课程节选

In other words, just want to know where the electron is somewhere within the shell radius of the ground state of atomic hydrogen anywhere.

换言之，我只是想知道,电子在哪,可以在氢原子基态下的半径,里面的任何地方。

麻省理工公开课 - 固态化学导论课程节选

It is the value of the radius of the ground state electron orbit in atomic hydrogen.

它就代表氢原子基态电子,的轨道半径。

麻省理工公开课 - 固态化学导论课程节选

What you see is that the radius changes with atomic number for constant electron number.

对于等电子数的粒子，离子半径随着,原子数的变化而变化。

麻省理工公开课 - 固态化学导论课程节选