\textbf{209.} The number of nonbonding electron pairs on the central atom in which ion is equal to the number of nonbonding electron pairs on the central atom of $\text{BrO}_2^-$?
\medskip
(1) $NCS^-$ \hfill (2) $NO_2^-$ \hfill (3) $PCl_4^-$ \hfill (4) $BF_4^-$
%% Page 21