So that's why we have this zero point here, and just to point out again and again and again, it's not a radial node, it's just a point where we're starting our graph, because we're multiplying it by r equals zero.

这就是为什么在这里有个零点，我需要再三强调，这不是径向零点，他只是我们画图的起始处，因为我们用ｒ等于０乘以它。

麻省理工公开课 - 化学原理课程节选

So, for example, we can move to the next periods in the periodic table. When we talk about a period, we're just talking about that principle quantum number, so period 2 means that we're talking about starting with the 2 s orbitals, period 3 starts with, what we're now filling into the 3 s orbitals here.

我们可以移至周期表的下一个周期,当我们讨论一个周期时，我们仅仅讨论,周期3以我们所填充的3s轨道，开始填充所以周期2意味着,我们从2s轨道谈起，周期3以我们所填充的3s轨道开始填充。

麻省理工公开课 - 化学原理课程节选

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