So whenever we're thinking about energy states, it's lways more stable to be more low in an energy well, so that's why it makes sense that it's favorable, in fact, to have an electron interacting with the nucleus that stabilizes and lowers the energy of that electron by doing so.

负的能量越多，能级越低,无论何时，能级总是越低越稳定,所以这就是为什么电子更,倾向于通过和原子核相互作用,来稳定并降低电子的能级。

麻省理工公开课 - 化学原理课程节选