Question

Draw the lewis structure of NCO⁻ (with minimized formal charges) and then choose the appropriate formal charges for each of the atoms.

A) N = 0, C = 0, 0 = -1 B) N = -1, C = +1, O = -1 C) N = 0, C = 0, 0 = 0 D) N = +1, C = -1, 0 = -1 E) N=-1, C = 0, 0 = 0

Answer 1

The stable Lewis structure of NCO⁻ has the formal charges -1 on nitrogen, and 0 on both carbon and oxygen, giving answer option E) N=-1, C = 0, O = 0. This places the negative charge on the more electronegative nitrogen, with carbon in the center forming double bonds to both nitrogen and oxygen.

Step-by-step explanation:

The Lewis structure of NCO⁻ that minimizes formal charges and is most stable has nitrogen (N) at -1, carbon (C) at 0, and oxygen (O) at 0, making the correct answer E) N=-1, C = 0, O = 0. When drawing the Lewis structure, the negative formal charge is on the more electronegative element (Guideline 4), and the least electronegative atom is insulated by double bonds to minimize formal charges on individual atoms.

Here's the Lewis structure for clarity:

• Nitrogen with a lone pair and a single bond to carbon.
• Carbon with a double bond to both nitrogen and oxygen.
• Oxygen with a double bond to carbon and two lone pairs.

Using guideline 2, which states to minimize the magnitude and number of formal charges, we see that nitrogen has a -1 charge, carbon is neutral (0), and oxygen is also neutral (0). In this configuration, the formal charges add up to the overall charge of the ion, which is -1.