LEWIS STRUCTURE OF NITROGEN DIOXIDE (NO2)
The Correct Answer and Explanation is:
The Lewis structure of Nitrogen Dioxide (NO₂) is drawn by following these steps:
1. Count the Total Valence Electrons:
Nitrogen (N) has 5 valence electrons
Oxygen (O) has 6 valence electrons each
Total = 5 + (6 × 2) = 17 electrons
Since NO₂ has an odd number of electrons, it is classified as a free radical.
2. Determine the Skeleton Structure:
Nitrogen is the central atom with two oxygen atoms bonded to it.
3. Place the Electrons:
- Create two N—O bonds
- Place lone pairs on the oxygen atoms to complete their octets
- The odd electron will be left as an unpaired electron on nitrogen
4. Lewis Structure of NO₂:
One oxygen forms a double bond with nitrogen, the other forms a single bond, and nitrogen holds the unpaired electron. The structure is:
mathematicaCopyEdit O
//
N — O
.
Formal Charges:
To minimize formal charges, one oxygen is double-bonded, the other is single-bonded with a negative charge, and nitrogen carries a positive charge.
Electron Domain Geometry:
- Three regions of electron density around nitrogen (two bonding pairs and one unpaired electron)
- Electron geometry is trigonal planar
Hybridization:
- Nitrogen uses sp² hybrid orbitals for bonding
Molecular Geometry:
- Due to the lone electron, the geometry is bent (V-shaped)
Approximate Bond Angle:
- About 120°
Polarity:
- NO₂ is polar due to its asymmetrical bent structure
Explanation:
Nitrogen dioxide is unique because it contains an odd number of electrons, making it a free radical. Despite its odd electron, NO₂ adopts a stable structure by delocalizing electrons and forming resonance structures. The bent molecular geometry causes unequal electron distribution, resulting in a polar molecule. The presence of an unpaired electron also makes NO₂ highly reactive, contributing to its role as an air pollutant and a participant in atmospheric chemical reactions.
