Why do both atomic size and ionic size increase as you move down a group?

1 Answer
Dec 24, 2017

This is a good question!

Basically, as we move down the periodic table, the size of the nucleus increases, and concomitantly more electrons are present to "shield" the valence electrons from the charge.

Anions are generally larger than cations. This has to do with the balance of effective nuclear charge put out by the nucleus versus the number of electrons present around the atom.

If there are many electrons, its harder to rope them up via electron charge than when there are less. It's like lasso'ing a bunch of sheep!