Which of the following statements correctly describes the Lewis dot structure of the neutral compound NCS-?

• A. The structure has a linear arrangement with nitrogen triple-bonded to carbon and carbon single-bonded to sulfur, with a negative charge on sulfur.
• B. The structure has a bent arrangement with nitrogen single-bonded to carbon and carbon double-bonded to sulfur, with a negative charge on nitrogen.
• C. The structure has a trigonal planar arrangement with nitrogen, carbon, and sulfur all single-bonded to each other, with no formal charges.
• D. The structure has a linear arrangement with nitrogen double-bonded to carbon and carbon double-bonded to sulfur, with a negative charge on carbon.

Answer: (A)

Verified step by step guidance

1. Identify the atoms involved in the NCS⁻ ion: nitrogen (N), carbon (C), and sulfur (S), and note that the overall charge is -1.
2. Determine the total number of valence electrons by adding the valence electrons of each atom and including the extra electron for the negative charge: N has 5, C has 4, S has 6, plus 1 extra electron for the charge.
3. Consider possible bonding arrangements and electron distributions that satisfy the octet rule for each atom while accounting for the total valence electrons and the negative charge.
4. Evaluate the formal charges for each atom in different Lewis structures to find the most stable arrangement, aiming for the lowest formal charges and placing the negative charge on the most electronegative atom.
5. Conclude that the most stable Lewis structure is linear with nitrogen triple-bonded to carbon and carbon single-bonded to sulfur, placing the negative charge on sulfur, which matches the correct description.