它是根据原子序数的增加来排列的，原子序数是一种元素单个原子的质子数。

It is arranged according to increasing atomic number, which is the number of protons in each atom of an element.

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And note that as Z increases, as the proton number increases the radius decreases for a given n number.

并注意到当Z不断增加，对于一个给定的n，即当质子数增加的时候,半径的n值就减小了。

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The same number of electrons, but the number of protons keeps going up, up, up.

他们都是等电子，但是质子数在增加。

麻省理工公开课 - 固态化学导论课程节选