Write the resonance structures of $CO_3^{2 - }$ and $HCO_3^ - $ .

Hint:The process of the delocalization of the $\pi - $ electrons in any compound which causes a lowering of the energy of the compound and thus, providing stability to it is known as resonance. The energy that is released from the compound while it undergoes resonance is known as resonance energy.

Complete step by step answer:
Under the complete framework of the valence bond theory, resonance is a simpler extension of the idea that the bonding between the atoms in a chemical species can be described with the help of a Lewis structure. For various chemical species, a single Lewis structure, consisting of atoms obeying the octet rule, possibly bearing formal charges, and connected by bonds of positive integer order, is sufficient for describing the chemical bonding and rationalizing experimentally determined molecular properties like bond lengths, angles, and dipole moment. However, in some cases, more than one Lewis structure could be drawn, and experimental properties are inconsistent with any one structure. In order to address this type of situation, several contributing structures are considered together as an average, and the molecule is said to be represented by a resonance hybrid in which several Lewis structures are used collectively to describe its true structure.
The resonance structures of $CO_3^{2 - }$ is as follows:

The resonance structures of $HCO_3^ - $ is as follows:


Note: The resonance hybrid represents the actual molecule as the average of the contributing structures, with bond lengths and partial charges taking on intermediate values as compared to those expected for the individual Lewis structures of the contributors, and if they were to exist as real chemical entities and not a hypothetical or imaginary entity.