So the 3 s 1, or any of the other electrons that are in the outer-most shell, those are what we call our valence electrons, and those are where all the excitement happens.

它们是经常发生激发情况的,那也是我们所看到，我们称之为价电子，它们是经常发生激发情况的。

麻省理工公开课 - 化学原理课程节选

Core electrons are all those electrons held in really tight with the nucleus in the inner shells, whereas the valence electrons are only those electrons that are in the outer-most shell, or at your highest value of n of the principal quantum number.

芯电子是那些,在内壳层被原子核束缚得非常紧的电子，而价电子只包括,最外层的电子，或者说主量子数，n，的值最大的那些电子。

麻省理工公开课 - 化学原理课程节选