So, here we have the area of the nuclei we'll figure out adding those all together versus the space of all of the atoms put together.

有原子核的面积,通过除以所有原子的,总面积。

麻省理工公开课 - 化学原理课程节选

Versus looking at, for example, helium or neon or argon, these are all inert gases, inert meaning essentially do not react, those were grouped together in the periodic table.

相反，他发现氦，氖，氩，都是惰性气体，惰性的意思是基本不参与化学反应，因此把它们放在周期表中的同一类里。

麻省理工公开课 - 化学原理课程节选