Explain the structure of $CO_{3}^{2-}$ ion in terms of resonance.

(N/A) The single Lewis structure based on the presence of two single bonds and one double bond between carbon and oxygen atoms is inadequate to represent the molecule accurately as it represents unequal bonds.
According to the experimental findings,all carbon to oxygen bonds in $CO_{3}^{2-}$ are equivalent.
Therefore,the carbonate ion is best described as a resonance hybrid of the canonical forms $I$,$II$,and $III$ as shown below:
$I \leftrightarrow II \leftrightarrow III$
(Where $I$,$II$,and $III$ represent the three equivalent Lewis structures with the double bond shifting between the three oxygen atoms.)