I mean they take up a teeny bit but essentially when we're thinking about the set up of the atom, we don't have to account for them as using up a lot of the mass we're discussing.

所以我们可以假设电子没有质量,它们占据了，非常小的一部分,所以当我们考虑,原子的构造的时候,不用考虑它们的质量。

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