Write the Lewis structure for each ion. Include resonance structures if necessary and assign formal charges to all atoms. If necessary, expand the octet on the central atom to lower formal charge for the following ions: a. PO4^3- b. CN^- c. SO3^2- d. ClO2^-.

Verified step by step guidance

1. <Step 1: Determine the total number of valence electrons for each ion. For polyatomic ions, add electrons for negative charges and subtract for positive charges.>
2. <Step 2: Write the skeletal structure of the ion, placing the least electronegative atom in the center (except for hydrogen).>
3. <Step 3: Distribute the valence electrons around the atoms, starting with the outer atoms, to satisfy the octet rule (or duet for hydrogen).>
4. <Step 4: If there are remaining electrons, place them on the central atom. If the central atom does not have a complete octet, consider forming double or triple bonds.>
5. <Step 5: Calculate the formal charge for each atom using the formula: Formal Charge = (Valence electrons) - (Non-bonding electrons) - 0.5*(Bonding electrons). Adjust the structure to minimize formal charges, expanding the octet if necessary.>