The correct formal charges on oxygen atoms numbered 2, 1 and 3 respectively are : [figure]
- 0, 0, 0
- −1, 0, +1
- +1, 0, −1
- 0, +1, −1
Answer
(4) 0, +1, −1
Solution
Formal charge (F.C.) = (valence electrons) − (non-bonding electrons) − ½ (bonding electrons)
O(1) (central, one lone pair, three bonds): F.C. = 6 − 2 − ½(6) = +1
O(2) (two lone pairs, double bond): F.C. = 6 − 4 − ½(4) = 0
O(3) (three lone pairs, single bond): F.C. = 6 − 6 − ½(2) = −1
∴ For atoms 2, 1 and 3: 0, +1, −1 (as in NCERT's Lewis structure of O3)
Answer: (4)