Question

The correct order of the decreasing ionic radii among the following isoelectronic species is

• A. $C{a}^{2+}>K^{+}>S^{2-}>C{l}^{-}$
  
• B. $C{l}^{-}>S^2->C{a}^{2+}>K^{+}$
  
• C. $S^{2-}>C{l}^{-}>K^{+}>C{a}^{2+}$
  
• D. $K^{+}>C{a}^{2+}>C{l}^{-}>S^{2-}$

Answer 1

The correct option is C

$S^{2-}>C{l}^{-}>K^{+}>C{a}^{2+}$

The order of ionic radii is same as the order of ratios of electrons to protons.