How does ionic radius change on the periodic table?

1 Answer
Jul 5, 2017

Well, we have a problem..........


Typically, metals, electron-rich materials, LOSE electrons to form CATIONS. And if they lose electrons, then the radius of the resultant ion should be DRAMATICALLY smaller than that of the parent atom - especially when we consider that the electrons are removed from the valence shell, which of course determines the atomic radius. On the other hand, non-metals, are electron-poor materials, and typically they gain electrons to form ANIONS, and these have DRAMATICALLY greater radii than their parent atoms.

The given picture is one I use a lot, and it certainly does illustrate what we have argued in the former: anions get larger; cations get smaller with respect to radii. Only problem is it quotes units of #"pm"-=10^-12*m#; a chemist would typically use #"Angstroms"#, i.e. #1xx10^-10*m#........