And the other thing to point out, which I don't know if this is true or not, but does anyone know -- well that's part's true, does anyone know what the atomic mass of lithium is?

另外需要指出的一点是，关于这点我不知道是不是真的，有人知道--这部分是真的，有人知道锂的原子量吗？

麻省理工公开课 - 化学原理课程节选

s1 Here is 1s atomic. But lithium has 2s1, so I need a 2s atomic orbital here and likewise over here.

这是1s原子，但锂有两层，所以我还需要在这里添加2s轨道,就像那样。

麻省理工公开课 - 固态化学导论课程节选

So similarly, as we now move up only one more atom in the table, 3 so to an atomic number of three or lithium, now we're going from six variables all the way to nine variables.

类似地就像我们现在,移动到周期表中仅仅多一个电子的情况，移动到一个原子数为，或者锂元素,现在我们从6个变量到了9个变量。

麻省理工公开课 - 化学原理课程节选

So, even though we don't have the lithium anymore, we still keep that atomic number 7 around.

尽管现在它不含锂了，但是作为原子量的七，还是在一定程度上保留了下来。

麻省理工公开课 - 化学原理课程节选