To determine the formal charges on atoms in a molecule, we use the formula:

$\text{Formal Charge}=(\text{Valence electrons})-(\text{Non-bonding electrons})-\frac{1}{2}(\text{Bonding electrons})$

Let's analyze the given structure of O\u2083:

${\text{O}}_a={\text{O}}_b={\text{O}}_c$

The central oxygen atom (b) is double-bonded to one oxygen atom (a) and single-bonded to another oxygen atom (c). The terminal oxygen atom (a) is double-bonded to the central oxygen atom (b) and has two lone pairs. The terminal oxygen atom (c) is single-bonded to the central oxygen atom (b) and has three lone pairs.

Step 1: Calculate formal charge on atom 'a' (double-bonded oxygen).

Atom 'a' has 6 valence electrons, 4 non-bonding electrons (2 lone pairs), and 4 bonding electrons (2 bonds).

${\text{Formal Charge}}_a=6-4-\frac{1}{2}(4)=6-4-2=0$

Step 2: Calculate formal charge on atom 'b' (central oxygen).

Atom 'b' has 6 valence electrons, 2 non-bonding electrons (1 lone pair), and 6 bonding electrons (3 bonds: one double bond and one single bond).

${\text{Formal Charge}}_b=6-2-\frac{1}{2}(6)=6-2-3=+1$

Step 3: Calculate formal charge on atom 'c' (single-bonded oxygen).

Atom 'c' has 6 valence electrons, 6 non-bonding electrons (3 lone pairs), and 2 bonding electrons (1 bond).

${\text{Formal Charge}}_c=6-6-\frac{1}{2}(2)=6-6-1=-1$

The question asks for the formal charges on 'a' and 'b' respectively. These are 0 and +1.

Option Analysis:

• A) \u20131, +1: Incorrect. The formal charge on 'a' is 0, not -1.
• B) +1, \u20131: Incorrect. The formal charge on 'a' is 0, not +1.
• C) 0, +1: Correct. The formal charge on 'a' is 0 and on 'b' is +1.
• D) +2, \u20131: Incorrect. The formal charges are 0 and +1, not +2 and -1.

Correct Answer: (C)