So what is actually going to matter is how closely that electron can penetrate to the nucleus, and what I mean by penetrate to the nucleus is is there probability density a decent amount that's very close to the nucleus.

所以实际上有关系的是,电子可以穿越至原子核有多近,我所指的穿越至原子核是,这里有一定数量的概率密度,可以距离原子核非常近。

麻省理工公开课 - 化学原理课程节选

s And if we go ahead and superimpose the 3 s on top of the 3 p, you can see that the 3 s actually has some bit of probability density that gets even closer to the nucleus than the 3 p did.

如果我们继续将,重叠到3p上面，你们会看到3s事实上,有一点概率密度,距离原子核更近,比3p轨道。

麻省理工公开课 - 化学原理课程节选