Why is the second ionization energy of an atom always higher than its first ionization energy? [ENDORSED]

[Yinhan_Liu_1D]

It's in the thinking point on P54.

I would appreciate your help.

[Yinhan_Liu_1D]

LOL... I think I get it.
The ionization here happens mostly within the first two groups.

In the first group, when the first ion is removed, we have to remove one ion from the core noble gas, which would be very hard, because it's already a stable formation.

[janavi_patel_2K]

I believe that this is because removing the second electron is always harder than removing the first electron. Once the first electron is removed, the electrostatic attraction energy increases and there is a net positive charge because one electron with a negative charge has already been removed. It takes much more energy to remove an electron from a positively charged ion than from a neutral atom.