# Comparing size of ions lithium, gallium ions

How is the size of $\ce{Li+}$ ($\pu{0.68}$) larger than $\ce{Ga^3+}$ ($0.62$)?

This is very difficult for me to understand why they say that size of Li+ with 3 protons and just 2 electrons should be considerably more than that of $\ce{Ga^3+}$. I understand the poor shielding effect of $\ce{3d^{10}}$ electrons but it isn't obvious to me why it will make its size smaller than $\ce{Li+}$ which has just one shell with 2 electrons and more effective nuclear charge. Where is my logic wrong?

• Because removing three electrons from Ga leaves a much stronger net positive charge, pulling in the orbitals, than pulling one from Li. Jun 11 '18 at 18:02
• We removed remove the 1 electron from 4p1 and then remove 2 electrons from 4s2 these three electrons where the ones on which the nucleus pulled on with more force but now they are not there. Jun 11 '18 at 18:55
• @drmoishepippik but what about Ga3+ containing 3 shells and Li only one? Jun 11 '18 at 18:57
• Could you link the source of the image? Jun 11 '18 at 20:24
• @holgerfielder chemistry.stackexchange.com/questions/98166/… Jun 12 '18 at 2:50