The reason is because the predominant force at this point is going to be the attraction that's being felt between the nuclei and the electrons in each of the atoms.

这是因为这时候最主要的力,是吸引力，它来自于,其中一个原子的电子与另外一个原子的原子核之间。

麻省理工公开课 - 化学原理课程节选

So, we can use Coulomb's force law to think and it does that, it tells us the force is a function of that distance. But what it does not tell us, which if we're trying to describe an atom we really want to know, is what happens to the distance as time passes?

来考虑这两个粒子之间的,它告诉我们力随距离的函数关系,但它不能告诉我们，而我们如果要描述,原子又非常想知道的是,距离随时间的变化时怎样的？

麻省理工公开课 - 化学原理课程节选

I am going to say if that electron is to stay in its orbit, that is to say it doesn't flee the atom, it doesn't collapse under the nucleus then the sum of the forces on the electron must be zero No net force. And so that will be the sum of a dynamic force plus an electrostatic.

如果电子会保持在它的轨道上运行,既不脱离原子的话，它就不会由于原子核对它的吸引力而被瓦解掉,电子所受的合力一定为零,由于没有合力,所以电子所受力为动态力和静电力的总和。

麻省理工公开课 - 固态化学导论课程节选