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^-.

Draw the Lewis structure for nitric acid, ensuring the hydrogen atom is attached to one of the oxygen atoms. Include all three resonance structures by alternating the double bond among the three oxygen atoms. Use formal charge to determine which of the resonance structures is most important to the structure of nitric acid.

Phosgene (Cl2CO) is a poisonous gas used as a chemical weapon during World War I. It is a potential agent for chemical terrorism today. Draw the Lewis structure of phosgene, including all three resonance forms by alternating the double bond among the three terminal atoms. Which resonance structure is the best?