d1 2 3 And we can do that just going along, 3 d 1, 2 3, and the problem comes when we get to chromium here, which is instead of what we would expect, 4s23d4 we might expect to see 4 s 2, 3 d 4.

我们能做的就是继续，问题出现了,当我们来到铬元素时，它不是我们预期的那样，我们可能预期。

麻省理工公开课 - 化学原理课程节选

I don't care how you do it on exams or on problem sets, but you do need to be aware that the 3 d once filled is lower in energy than the 4 s, and the reason you need to be aware of that is if you're asked for the electron configuration now of the titanium ion.

我不关心你们在考试或者,问题集中如何做它，但是你们的确需要知道3d一旦被填充,它的能量是小于4s的，你们需要知道这个的原因,是如果你现在被要求,写出钛离子的电子构型。

麻省理工公开课 - 化学原理课程节选