So, we have beryllium in the first case here, it has four electrons, that's how we know it's beryllium, boron has five electrons.

那么我们将铍作为第一个例子，它有四个电子，这也是我们为什么能知道它是铍的原因，硼有五个电子。

麻省理工公开课 - 化学原理课程节选

And the glitch that doesn't make sense just through periodic trends, is that it turns out that the ionization energy of boron is actually less than the ionization energy up beryllium.

仅仅考虑周期性规律,是无法理解这个问题的，这里显示硼的电离能,实际上比铍的要小。

麻省理工公开课 - 化学原理课程节选

Look at beryllium 2 plus, very tiny, charge plus two.

例如铍二正离子，非常小，带2个单位正电。

麻省理工公开课 - 固态化学导论课程节选

So what I want to point out with this case in beryllium is that you don't have to use all of the electrons to figure out the bond order, and in fact, once you get to molecules 10 that are from atoms with atomic numbers of 8 or 10, you're not going to want to maybe draw out the full molecular orbital diagram.

我要指出的是,在Be这种情况下,你不需要利用,所有的电子来指导键序，实际上，一旦分子中,原子序数到达了8或者，你也许不想画出,整个分子轨道图。

麻省理工公开课 - 化学原理课程节选