Plz help me understand this...?

Question

I was reading my chemistry text book but I don't under stand this section its on Variation in successive Ionization Energies.

The sharp increase in ionization energy that occurs when an inner-shell electron is removed.

For example Silicon: Whose electron configuration is 1s^2 2s^2...etc.. or [Ne] 3s^2 3p^2

The ionization energies increase steadily from 786 kJ/mol to 4360 kJ/mol for the lost of four electron.

Well my question is how did they get the number 786 to 4360?

Thank you very much!!1

Answer 1

There are probably 2 answers to your question:

The textbook writers got it by looking at a previously published table.

However, the ionization energies were originally probably found via several methods, including experimentation, Koopmans' theorem, and analyzing the electrostatic potential.