So, the size still for an s orbital is larger than for a d orbital, but what we say is that an s electron can actually penetrate closer to the nucleus.

轨道的尺寸比,ｐ轨道还是要大，但我们说的是ｓ轨道可以,穿透到更接近原子核的地方。

麻省理工公开课 - 化学原理课程节选

Soon when we're talking about multi-electron atoms, and I just want to introduce it here, that it is sort of opposing ideas that even though the s is the biggest and it's most likely that the electron's going to be furthest away from the nucleus, that's also the orbital in which the electron can, in fact, penetrate closest.

当我们说多电子原子时，我这里要先介绍一下，这些概念有些相反,虽然ｓ轨道最大,所以电子最可能远离原子核，但它上面的最容易，穿透到离原子核最近。

麻省理工公开课 - 化学原理课程节选