There are several groups. One,called the Counting Club, is for children who love working with numbers.

VOA: special.2010.12.28

So now we're just counting up our orbitals, an orbital is completely described by the 3 quantum numbers.

所以现在我们只要把这些轨道加起来，一个轨道是由３个量子数完全确定的。

麻省理工公开课 - 化学原理课程节选