Class 11 NEET Chemistry Chemical Bonding And Molecular Structure Part 2

Concept:Formal charge is the charge on an atom assuming equal sharing of bonding electrons. It is calculated as: Valence electrons − (Lone pair electrons + ½ × Bonding electrons).Chemical Equation / Formula:For oxygen: Valence electrons = 6.Formal charge = $6 - \left(\text{lone pairs} + \frac{1}{2} \times \text{bonding electrons}\right)$.Explanation:From the structure (ozone), the oxygen atoms are numbered 2, 1, and 3 as shown in the image.• Oxygen 2 (terminal, double‑bonded): It has 1 double bond (4 bonding electrons) and 2 lone pairs (4 electrons). Formal charge = $6 - \left(4 + \frac{1}{2}\times4\right) = 6 - (4+2) = 0$.• Oxygen 1 (central): It has 1 double bond and 1 single bond (total 6 bonding electrons) and 1 lone pair (2 electrons). Formal charge = $6 - \left(2 + \frac{1}{2}\times6\right) = 6 - (2+3) = +1$.• Oxygen 3 (terminal, single‑bonded): It has 1 single bond (2 bonding electrons) and 3 lone pairs (6 electrons). Formal charge = $6 - \left(6 + \frac{1}{2}\times2\right) = 6 - (6+1) = -1$.Thus the charges on oxygen atoms 2, 1, and 3 are 0, +1, and –1 respectively.Shortcut:In ozone, the central oxygen (with one double and one single bond) always has +1, the terminal with a double bond has 0, and the terminal with a single bond has –1. Here O1 is central, O2 is double‑bonded terminal, O3 is single‑bonded terminal. So order (O2, O1, O3) gives (0, +1, –1).Answer:Option B: $0, +1, -1$