At this point, we have no other choice but to double up before going to the next energy level, 2px so we'll put a second one in the 2 p x.

在这点上我们没有其他选择,而只有双倍填充,在到下一个能级之前，所以我们放入第二个电子至。

麻省理工公开课 - 化学原理课程节选

I'll put double crosses for "in the second round" 2 and 9.

我在第二次推理上画两个叉,立场2和9

耶鲁公开课 - 博弈论课程节选