The only thing that's different is that they're one down on the periodic table, potassium is down one row, so it's going to be a little bigger, but when we're thinking about size, it maybe does not seem that significant to talk about the size.

它们唯一的不同点,就在于其中一个在周期表的下面，钾在下一行，因此它要稍微大一些，但是当我们考虑尺寸的时候，似乎讨论尺寸的意义不大。

麻省理工公开课 - 化学原理课程节选