Which of the following statements correctly describes the Lewis dot structure of the BrO2^- ion?

• A. BrO2^- has a bromine atom bonded to two oxygen atoms, with the negative charge located on the bromine atom.
• B. BrO2^- has a bromine atom bonded to one oxygen atom and one hydrogen atom, with the negative charge on bromine.
• C. BrO2^- has a bromine atom bonded to two oxygen atoms, with both oxygen atoms carrying a negative formal charge.
• D. BrO2^- has a bromine atom bonded to two oxygen atoms, with one oxygen atom carrying a negative formal charge.

Answer: (D)

Verified step by step guidance

1. Identify the total number of valence electrons available for the BrO2^- ion. Bromine (Br) has 7 valence electrons, each oxygen (O) has 6 valence electrons, and the negative charge adds 1 extra electron. So, total valence electrons = 7 + 2×6 + 1.
2. Draw a skeletal structure with bromine as the central atom bonded to two oxygen atoms. This is because bromine is less electronegative than oxygen and typically serves as the central atom in such oxyanions.
3. Distribute the electrons to satisfy the octet rule for each atom. Start by placing bonding pairs between Br and each O, then assign lone pairs to complete the octets of the oxygen atoms first, as oxygen is more electronegative.
4. Calculate the formal charges on each atom using the formula: Formal charge = (Valence electrons) - (Nonbonding electrons) - 1/2(Bonding electrons). Adjust the electron distribution if necessary to minimize formal charges, keeping in mind that the negative charge is usually localized on the more electronegative atom.
5. Conclude that the most stable Lewis structure for BrO2^- has bromine bonded to two oxygen atoms, with one oxygen atom carrying a negative formal charge, while bromine and the other oxygen have formal charges close to zero.