Chemistry - PERIODIC TABLE Question with Solution | TestHub

Concept: Ionic radius decreases with increasing nuclear charge for isoelectronic species and increases down a group.

Order (largest → smallest):

K⁺ > Ca²⁺ > Li⁺ > Mg²⁺

P(${\mathrm{Mg}}^{2+}$): 0.72 Å

Q(${\mathrm{K}}^{+}$): 1.37 Å

R(${\mathrm{Li}}^{+}$): 0.76 Å

S(${\mathrm{Ca}}^{2+}$): 1.00 Å