Core Periodicity III: Ionization Energy & Electron Affinity

Core Periodicity: Ionization Energy & Electron Affinity

Slide 14 of 28

Explanation

Going down a group note:

1. the nuclear charge increases dramatically from one to the next element (a factor that contributes to electrostatic force of attraction between the nucleus and an electron)

2. the distance between the valence shell and nucleus increases (a factor that in general reduces electrostatic force of attraction)

However, the effect of increase in distance on the electrostatic force of attraction more than compensates for effect of the increase in nuclear charge.

In general, between chemical species (atoms or ions) that have different number of shells, the one with the higher number of shells will have the lower ionization energy.