Write the resonance structures for $SO_{3}$,$NO_{2}$ and $NO_{3}^{-}$.

(N/A) The resonance structures are represented by the following diagrams:
$1$. For $SO_{3}$:
$[:O=S(-O:)(-O:)] \leftrightarrow [:O-S(=O:)(-O:)] \leftrightarrow [:O-S(-O:)(=O:)]$
$2$. For $NO_{2}$:
$[:O=N-O:] \leftrightarrow [:O-N=O:]$
$3$. For $NO_{3}^{-}$:
$[:O^{-}-N(=O:)(-O:)] \leftrightarrow [:O=N(-O^{-})(-O:)] \leftrightarrow [:O=N(-O:)(-O^{-})]$