Browse Questions

# The radii of F, O, F$^{-}$ and O$^{2-}$ follows which of the following orders:

$\begin{array}{1 1} F < O < F^{-} < O^{2-} \\ F^{-} < O^{2-} < F < O \\ F < F^{-} < O < O^{2-} \\ O < O^{2-} < F < F^{-} \end{array}$

Answer: F < O < F$^{-}$ < O$^{2-}$
Across a period, atomic radius decreases, the radius of F is less than the radius of O.
O$^{2-}$ and F$^{-}$ are isoelectronic ions $\rightarrow$ their ionic radis is inversely propotional to the effective nuclear charge.
$\Rightarrow r_{F^{-}} \lt r_{O^{2-}}$
Therefore the correct order is F < O < F$^{-}$ < O$^{2-}$