The $\mathrm{O}-\mathrm{N}-\mathrm{O}$ bond angle in the nitrite ion, ${{\mathrm{NO}}_2}^{-}$ , is closest to:

The structure o- can be${{\mathrm{NO}}_2}^{-}$ given as,

The $\mathrm{O}-\mathrm{N}-\mathrm{O}$ bond angle in the nitrite ion, ${{\mathrm{NO}}_2}^{-}$ ,  is 120 degree.  The nitrite ion has 115.4°$\mathrm{O}-\mathrm{N}-\mathrm{O}$ bond angle, (according to Gillespie and Hargittai).