How many resonating structures can be drawn for `NO_2`?

Options

A. Six
B. Four
C. Five
D. Two

Explanation

To determine the number of resonating structures for the molecule nitrogen dioxide (NO₂), we can follow these steps:

### Step 1: Calculate the Total Number of Valence Electrons
- **Nitrogen (N)** has 5 valence electrons.
- Each **Oxygen (O)** atom has 6 valence electrons, and since there are 2 oxygen atoms, that totals to 12 valence electrons.
- Therefore, the total number of valence electrons in NO₂ is:
\[ 5 + 6 + 6 = 17 \text{ valence electrons} \]

### Step 2: Draw the Basic Structure
- Start by placing the nitrogen atom in the center and the two oxygen atoms on either side.
- Connect the nitrogen atom to each oxygen atom with single bonds initially.

### Step 3: Distribute the Remaining Electrons
- After placing the single bonds, we have used 4 electrons (2 bonds).
- This leaves us with \( 17 - 4 = 13 \) electrons to distribute.
- Place lone pairs on the oxygen atoms to satisfy their octet. Each oxygen can hold 6 electrons (3 lone pairs) after forming a bond with nitrogen.

### Step 4: Check the Octet Rule
- In the initial structure, nitrogen has only 4 electrons (from 2 single bonds) and does not satisfy the octet rule.
- Oxygen atoms have 8 electrons each (2 from the bond and 6 from lone pairs), satisfying their octet.

### Step 5: Create Resonating Structures
- To satisfy the octet rule for nitrogen, we can create double bonds with one of the oxygen atoms:
- **First Resonating Structure**: One oxygen has a double bond with nitrogen, while the other has a single bond.
- **Second Resonating Structure**: The positions of the double and single bonds can be switched, creating a second valid structure.

### Step 6: Count the Resonating Structures
- The two structures we have drawn represent the two possible resonating forms of NO₂:
1. O=N-O (with one double bond and one single bond)
2. O-N=O (with the double bond on the other oxygen)

### Conclusion
Thus, the total number of resonating structures for NO₂ is **2**.

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