The positive force of attraction of the electrons on the outside is greater and greater, and that pulls everything in.

所以对外层电子的吸引力,会越来越强，把电子们都向内吸引。

麻省理工公开课 - 固态化学导论课程节选

Everything inside the parenthesis is positive, so minus a positive number.

而其中间的一切,也是正数，所以正数的相反是负数。

麻省理工公开课 - 固态化学导论课程节选