Draw the Lewis structure for N3 (You can use the back of sheet to draw LS).
The correct answer and explanation is :
The Lewis structure for the azide ion (N₃⁻) consists of three nitrogen atoms connected in a linear arrangement. To construct the correct Lewis structure, follow these steps:
Step 1: Count the Valence Electrons
- Nitrogen (N) has 5 valence electrons.
- Since there are three nitrogen atoms, the total valence electrons from nitrogen atoms = 5 × 3 = 15.
- The negative charge (⁻1) means one additional electron, making the total 16 valence electrons.
Step 2: Draw a Skeleton Structure
- The three nitrogen atoms are placed linearly: N – N – N.
Step 3: Distribute Electrons
- Assign single bonds between nitrogen atoms:
N – N – N (uses 2 electrons). - Distribute remaining 14 electrons to satisfy the octet rule.
- To satisfy the octet rule, resonance structures are considered.
Step 4: Assign Formal Charges
Formal charge is calculated as:
[
\text{Formal Charge} = \text{Valence Electrons} – \text{Nonbonding Electrons} – \frac{\text{Bonding Electrons}}{2}
]
The best Lewis structure has two possible resonance forms:
- [N≡N–N]⁻
- [N–N≡N]⁻
- The central nitrogen carries a +1 charge.
- One terminal nitrogen has a -1 charge.
- The overall charge remains -1.
Conclusion
The azide ion (N₃⁻) exhibits resonance, making it more stable. It has a linear shape and sp hybridization. Due to delocalized electrons, azide is highly reactive, often used in explosives like sodium azide (NaN₃).