What trends do you see on the periodic table for Ionization energy? What causes these trends?
1 Answer
Well, ionization energy..........[INCREASES across a Period.......](https://socratic.org/questions/why-does-ionization-energy-change-on-the-periodic-table)
Explanation:
Well, ionization energy INCREASES across a Period, an horizontal row of the Periodic Table from LEFT to RIGHT as we face the Table, and DECREASES down a Group, a column of the Periodic Table.
Two factors, influence this trend: (i) Nuclear Charge, and (ii) shielding by other electrons.
See here and [here.](https://socratic.org/questions/why-does-ionization-energy-change-on-the-periodic-table) Incomplete electronic shells shield the nuclear charge VERY ineffectively. And thus across the Period, the atomic radii markedly contract - this is a macroscopic variable that you should investigate. Once a valence shell is completed, shielding becomes reasonably effective, and electrons add to a valence shell farther removed from the nuclear core.
