Which of the following statements correctly describes the Lewis dot structure of the bromate ion, BrO_3^-?

• A. BrO_3^- has two single bonds and one triple bond between Br and the O atoms, with the negative charge on bromine.
• B. BrO_3^- has three double bonds between Br and each O atom, with no formal charges on any atom.
• C. BrO_3^- has three single bonds between Br and each O atom, with one oxygen atom carrying a negative formal charge.
• D. BrO_3^- has three single bonds between Br and each O atom, with the negative charge on bromine.

Answer: (C)

Verified step by step guidance

1. Step 1: Determine the total number of valence electrons available for the BrO_3^- ion. Bromine (Br) has 7 valence electrons, each oxygen (O) has 6 valence electrons, and there is an extra electron due to the negative charge. So, total valence electrons = 7 + 3 × 6 + 1.
2. Step 2: Draw a skeletal structure with bromine as the central atom bonded to three oxygen atoms. Connect each oxygen to bromine with a single bond initially.
3. Step 3: Distribute the remaining valence electrons to satisfy the octet rule for oxygen atoms first, placing lone pairs on oxygens to complete their octets.
4. Step 4: Check the formal charges on each atom using the formula: \(\text{Formal charge} = \text{Valence electrons} - \text{Nonbonding electrons} - \frac{1}{2} \times \text{Bonding electrons}\). Adjust bonding (single, double, or triple bonds) if necessary to minimize formal charges and place the negative charge on the most electronegative atom (oxygen).
5. Step 5: Confirm that the final Lewis structure has bromine bonded to three oxygens with single bonds, one oxygen carrying the negative charge (formal charge of -1), and all atoms having formal charges as close to zero as possible, consistent with the known structure of BrO_3^-.