Question

What is the formal charge in Sulphur of $SO_{3}$

• A. -1
• B. -1/2
• C. +1
• D. 0

Hint:

Formal charge is minimized in the most stable structure. For $SO_3$, the structure with zero formal charges is the most representative.

Answer 1

The Correct Option is D

Step 1: Concept
Formal charge is calculated as: $FC = (\text{Valence electrons}) - (\text{Non-bonding electrons}) - \frac{1}{2}(\text{Bonding electrons})$.

Step 2: Meaning
For $SO_3$, the most stable Lewis structure features Sulphur double-bonded to all three Oxygen atoms to minimize formal charges.

Step 3: Analysis
Sulphur has 6 valence electrons. In the structure with three double bonds, it has 0 lone pair electrons and 12 bonding electrons (6 bonds).
$FC = 6 - 0 - \frac{1}{2}(12) = 6 - 6 = 0$.

Step 4: Conclusion
The formal charge on the Sulphur atom in $SO_3$ is 0. Final Answer: (D)