Explain why `CO_(3)^(2-)` ion cannot be represented by a single Lewis structure. How can it be best represented ?

Explanation

A single Lewis streucture of `CO_(3)^(2-)` ion connot explain all the properites of this ion. It can be represented as
a resonance hybrid of the following structures :

If it were represented only by one structer, there should be two types of bonds , i.e., C= O double bond and
C-O single bonds but actually all bonds are found to be identical with same bond length and same bond
strenth.