It makes sense, right, because they're the furthest away from the nucleus, they're the ones that are most willing to be involved in some chemistry or in some bonding, or those are the orbitals that are most likely to accept an electron from another atom, for example. So the valence electrons, those are the exciting ones.

它讲得通，对，因为它们距离,原子核最远，它们是最容易发生,化学反应和结合的地方，另一个原子的电子的轨道或者它们是,最容易接受，举个例子所以价电子，他们是活跃的电子。

麻省理工公开课 - 化学原理课程节选