Answer:
Claim: The jump in ionization energy from I2 to I3 is the largest.
Evidence: You would have to search some up but the jump is from 1450.7 kj/mole to 7732.7 kj/mole. You could also say that magnesium has an electron configuration of [Ne] 3s2 and after removing the two outer valance electrons the next electrons being removed would be core electrons.
Reasoning: Core electrons need lots of energy to remove from the atom, while valance electrons are easy to remove. The 2nd electron removed is a valance electron, while the 3rd electron removed is a core electron. Thus, we should expect that the energy needed to remove a hard to remove electron (the 3rd electron) would be much more than the energy needed to remove the easy to remove electron (2nd) and we should expect a large jump of ionization energy from I2 to I3.