If you click on Courseware you will get to this menu, the first of which preferences is Periodic Table.

如果你点击课件，就会来到这个菜单，第一个选择就是周期表。

麻省理工公开课 - 固态化学导论课程节选

So if we're talking about the third period, that starts with sodium and it goes all the way up to argon.

所以如果我们谈论第3个周期，它从钠开始,一直到氩。

麻省理工公开课 - 化学原理课程节选

It decreases. If you're still not completely up on the periodic trends, that is stuff that's going to be on the first exam, so make sure that you're able to do this without taking too much time to think about it.

它会降低，如果你还没有完全掌握周期性规律，而这是第一次考试要求的内容，因此请务必做到不用,想太久就能做到这点。

麻省理工公开课 - 化学原理课程节选