Why does ionization energy increase on the periodic table?

1 Answer
Feb 17, 2017

Because of the increase in nuclear charge across the Period from left to right, as we face it.........


See this old answer. Ionization energy depends on (i) nuclear charge (i.e. #"Z, the atomic number"#), (ii) shielding by other electrons. As explained in the link, shielding of the nuclear charge by electrons in partly-filled valence shells, is VERY ineffective.