Question

How does ionic radius change across each period?

Answer 1

This would be an unusual comparison..........

Explanation:

Metals, to the left of the Periodic Table (as we face the Table), are electron rich substances. Upon oxidation, they lose electrons to form SMALLER metal ions (with respect to the metal atoms).

On the other hand, non-metals, to the right hand side of the Periodic Table as we face it, are electron-poor materials, in which the nuclear charge holds the valence electrons tightly. Non-metals, especially oxygen and fluorine, are thus OXIDIZING species, that tend to gain electrons, and the resultant ion should be larger than the parent atom. To address the original question then (at last!), ionic radii should increase across the Period from our left to our right.

In order to answer your question properly you should reference the ionic radii of selected metal and non-metal ions.