N2 Lewis structure
The n2 lewis structure represents the nitrogen molecule N2 as two nitrogen atoms sharing three electron pairs (a triple bond), with one lone pair remaining on each atom.
Direct result
N2: N≡N with one lone pair on each nitrogen, giving an octet on both atoms and formal charge 0 on each nitrogen.
Valence-electron accounting
Nitrogen is in group 15, so each nitrogen atom contributes 5 valence electrons. The molecule contains two nitrogen atoms, giving a total valence-electron count of \(2 \times 5 = 10\).
A triple bond places 6 electrons between the atoms, and the remaining 4 electrons appear as one lone pair on each nitrogen (2 electrons per lone pair). The diagram therefore accounts for all 10 valence electrons.
Bonding and octets
Each nitrogen in N2 satisfies the octet rule in the Lewis picture by having 8 electrons in its valence shell when bonding electrons are shared: 6 electrons in the bonding region (counted as 3 shared pairs) plus 2 electrons as a lone pair.
Formal charge verification
Formal charge provides a consistency check for a proposed Lewis structure. For one nitrogen atom in N2:
\( \text{FC} = \text{valence} - \left(\text{nonbonding} + \dfrac{\text{bonding}}{2}\right) \)
For nitrogen: valence \(= 5\), nonbonding \(= 2\) (one lone pair), bonding \(= 6\) (triple bond), so \( \text{FC} = 5 - \left(2 + \dfrac{6}{2}\right) = 5 - (2 + 3) = 0 \).
A zero formal charge on both atoms matches the most stable, standard Lewis representation for N2.
Summary table
| Feature | Value | Meaning in the Lewis picture |
|---|---|---|
| Total valence electrons | 10 | Two nitrogen atoms contribute 5 each. |
| Bond type | Triple bond (N≡N) | Three shared electron pairs between the atoms. |
| Lone pairs | 1 on each N | Two nonbonding electrons remain on each nitrogen. |
| Formal charge | 0 on each N | Electron assignment matches the neutral atoms in a stable arrangement. |
| Bond order | 3 | Three bonding pairs correspond to a strong, short bond. |
Common pitfalls
A double bond representation (N=N) fails the octet requirement unless additional electrons are assigned in a way that produces nonzero formal charges. A single bond representation (N–N) cannot satisfy octets with only 10 total valence electrons. The triple bond with one lone pair on each atom is the consistent neutral structure for N2.