Which of the following compounds or ions exhibit resonance? a. \(\mathrm{O}_{3}\) b. CNO- c. \(A s I_{3}\) d. \(\mathrm{CO}_{3}^{2-}\) \(\mathbf{e}, \quad A s F_{3}\)

First, we will draw the Lewis structures for each compound/ion to analyze their electronic structure. a. O3: Oxygen has 6 valence electrons, so the central oxygen atom will share 2 electrons with each of the other two oxygen atoms, making a single bond with each of them. The non-bonding electrons will be the lone pairs. b. CNO-: Carbon has 4 valence electrons, nitrogen has 5, and oxygen has 6. In this case, we'll need single, double, and triple bonds to achieve their respective octets, while the negative charge on the compound represents one extra electron. c. AsI3: Arsenic has 5 valence electrons, and iodine has 7. The central arsenic atom will make single bonds with each of the three iodine atoms to achieve its octet. d. CO3^(2-): Carbon has 4 valence electrons, while oxygen has 6. The central carbon will form single/double bonds with the oxygen atoms. The ion has a charge of -2, which means there are two extra electrons available. e. AsF3: Arsenic has 5 valence electrons and fluorine has 7. The central arsenic atom will form single bonds with each of the three fluorine atoms.

We will examine each Lewis structure and determine if it has resonance structures. a. O3: Two resonance structures can be formed by changing the location of the double bond between the oxygens. This compound exhibits resonance. b. CNO-: The compound has multiple resonance structures by changing the location of the double and triple bonds. The ions can be arranged in C-N≡O, or C=N=O, or N≡C-O configurations among others. Thus, CNO- exhibits resonance. c. AsI3: Arsenic and iodine atoms are both satisfied with their octets in the drawn structure and neither can form additional bonds due to their octet requirement. Hence, no resonance occurs in AsI3. d. CO3^(2-): The carbonate ion, CO3^(2-), exhibits resonance because there are several valid Lewis structures that can be made by moving the double bond to different oxygen atoms, while maintaining the overall negative charge. e. AsF3: Similar to AsI3, arsenic and fluorine atoms are satisfied with their octets with the existing single bonds. There is no possibility of forming additional bonds without violating octet rule; therefore, no resonance occurs in AsF3. In conclusion, the compounds/ions that exhibit resonance are \(O_3\), CNO-, and \(\mathrm{CO}_{3}^{2-}\).