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.........

Explanation:

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.