Question

The formal charges of atoms (1), (2) and (3) in the ion \[ \left[\overset{(1)}{O}=\overset{(2)}{N}=\overset{(3)}{O}\right]^+ \] is

• A. \(0,\;+2,\;-1\)
• B. \(0,\;+1,\;0\)
• C. \(+2,\;0,\;-1\)
• D. \(+1,\;0,\;0\)

Hint:

For formal charge calculations: \[ \text{F.C.}= V-L-\frac{B}{2} \] where \(V\) is valence electrons, \(L\) is lone-pair electrons and \(B\) is bonding electrons.

Answer 1

The Correct Option is B

Step 1: Write the formula for formal charge.
Formal charge is calculated using \[ \text{F.C.}= \text{Valence electrons} - \text{Non-bonding electrons} - \frac{1}{2} (\text{Bonding electrons}) \]

Step 2: Calculate formal charge on atom (1).
Atom (1) is oxygen.
Valence electrons in oxygen: \[ 6 \] Non-bonding electrons on oxygen: \[ 4 \] Bonding electrons in the double bond: \[ 4 \] Therefore, \[ \text{F.C. on }O = 6-4-\frac{4}{2} \] \[ =6-4-2 \] \[ =0 \]

Step 3: Calculate formal charge on atom (2).
Atom (2) is nitrogen.
Valence electrons in nitrogen: \[ 5 \] Non-bonding electrons: \[ 0 \] Bonding electrons: \[ 8 \] Thus, \[ \text{F.C. on }N = 5-0-\frac{8}{2} \] \[ =5-4 \] \[ =+1 \]

Step 4: Calculate formal charge on atom (3).
The second oxygen atom also has a double bond with nitrogen.
Thus, \[ \text{F.C. on }O=0 \]

Step 5: Final conclusion.
Hence, the formal charges on atoms \((1), (2)\) and \((3)\) are \[ \boxed{0,\;+1,\;0} \]