Question

The correct order of radii is
A. `N lt Be lt B`
B. `F^(ɵ)lt O^(2-) lt N^(3-)`
C. `Na lt Li lt K`
D. `Fe^(3+)lt Fe^(2+)lt Fe^(4+)`

Answer 1

Correct Answer - B
`F^(ɵ) lt O^(2-) lt N^(3-)`
All of these are isoelectronic ions (10 electrons).
In isolectronic species, as the number of protons (atomic number) goes on increasing, size goes on decreasing due to stronger attraction on the electrons (Z for N, O and F=7, 8 and 9).