That is to say the ionization energy of the second most electron.

这是二级电离能，这就是说，电子数第二多的电离能。

youdao

One major difference between electron affinity and ionization energy is that when we talked about ionization energy, remember ionization energy always has to be positive.

电子亲和能，与电离能之间最大的不同就在于，当我们提到电离能的时候，记得电离能总是正的。

youdao

So, second ionization energy simply means you've already taken one electron out, now how much energy does it take for you to take a second electron out.

第二电离能简单地说就是，在你已经拿走一个电子以后，再拿走第二个电子，所需要消耗的能量。

youdao

So we are really looking at this reaction here H+ for ionization. It is H gas neutral goes to H plus in the gas phase plus the electron. And, furthermore, we can have multiple ionization energies.

所以我们真正看到的是,电离，它是在气相中H变为,和电子的过程，还有，我们能电离能加倍。

麻省理工公开课 - 固态化学导论课程节选