The correct order of radii is

Options

A. `N lt Be lt B`
B. `F^(-) lt O^(2-) lt N^(3-)`
C. `Na lt Li lt K`
D. `Fe^(3+) lt Fe^(2+) lt Fe^(4+)`

Answer

B

Explanation

These are isolectronic species , thus , the ionic radius in inversely proportional to the nuclear charged `(Z)`:
`F^(-) (9) lt O^(2-) (8)lt N^(3-) (7)`
Other orders are
`N(70 "pm") lt B (82) lt Be (89)`
`Li (123 "pm") lt Na (156) lt K (203)`
`Fe^(4+) lt Fe^(3+) lt Fe^(2+)`