Answer to Question #153707 in General Chemistry for lee

Question

Explain why the difference between the second and third ionisation energies of calcium is much larger than the difference between the first and second ionisation energies.

Answer 1

Calcuim has 4 electron shells, however two electrons are in its outermost shell (the N shell). The second ionization energy will be larger than the first but still comparable because both electrons are being removed from the same energy level. The third electron is much more difficult to remove because it is being removed from a lower energy level (M shell), so it will have a much higher ionization energy than the other two.