What is the formal charge on the central carbon atom in the most likely Lewis structure of the thiocyanate ion (SCN−)?

• A. +1
• B. 0
• C. -1
• D. +2

Answer: (B)

Verified step by step guidance

1. Identify the atoms involved in the thiocyanate ion (SCN⁻): sulfur (S), carbon (C), and nitrogen (N), with an overall charge of -1 on the ion.
2. Draw the most likely Lewis structure for SCN⁻, placing carbon as the central atom bonded to sulfur and nitrogen. Consider possible multiple bonds to satisfy the octet rule for each atom.
3. Count the valence electrons for each atom: sulfur has 6, carbon has 4, nitrogen has 5, and add 1 extra electron for the negative charge, then sum all to find the total valence electrons available.
4. Assign electrons in the Lewis structure: distribute bonding and lone pairs to satisfy the octet rule, then determine the number of electrons 'owned' by the central carbon atom (count all lone pair electrons on carbon plus half the bonding electrons).
5. Calculate the formal charge on carbon using the formula: \(\text{Formal Charge} = \text{Valence electrons} - \text{Nonbonding electrons} - \frac{1}{2} \times \text{Bonding electrons}\). This will give the formal charge on the central carbon atom.