So, if you look in chapter one, you will find these definitions for different atomic groupings starting down here with the elements and moving through up through complex matter.

如果你们读第一章，你们会发现不同的原子组的定义,从底下开始有一些基本原理,往上还有复杂的物质。

麻省理工公开课 - 固态化学导论课程节选

All of these from the group one and two through the group five and six elements, but what about elements, what about molecules like hydrogen, or nitrogen, or maybe oxygen?

所有的这些都是来自于第一主族和第二组主族,到第五主族和第六组主族的悬殊，那么元素呢，比如氢气，氮气或氧气那样的分子呢？

麻省理工公开课 - 固态化学导论课程节选