1
Parse the ion formula
NO3- -> N, O, O, O
The ion contains one nitrogen atom and three oxygen atoms.
Lewis Structure
NO3- Lewis Structure
Nitrate ion
NO3- has three equivalent resonance forms. One form is shown with one N=O bond and two N-O- bonds.
Use the diagram and steps below to check the nitrate ion Lewis structure, NO3- Lewis dot structure, valence electrons, formal charges, and molecular shape.
Nitrogen must obey the octet rule, so the shown resonance form has N with +1 and two single-bonded oxygens with -1.
NO3-
Nitrate ion
Valence electrons24
Central atomN
GeometryTrigonal planar
Bond angleAbout 120 deg
PolarityIon
Electron geometryTrigonal planar
VSEPR Geometry
Molecular geometry
Trigonal planar
Electron geometry
Trigonal planar
Bond angle
About 120 deg
Polarity
Ion
Valence electrons
24
Bonding / lone pairs
3 / 0 around N
Central atom
N
Electron regions
3
How to Draw NO3-: Step-by-Step
2
Count total valence electrons
5 + 18 + 1 = 24
Add 1 electron for the negative charge.
3
Choose the central atom
Central atom: N
Nitrogen is placed in the center with three oxygens around it.
4
Draw one resonance form
One N=O and two N-O bonds
Nitrogen has +1 formal charge and the two single-bonded oxygens are -1 each.
5
Check resonance
3 equivalent forms
The N=O double bond can be placed on any one oxygen.
6
Final answer
The NO3- Lewis structure has three equivalent resonance forms. In one form, nitrogen has one N=O double bond and two N-O single bonds; the single-bonded oxygen atoms carry -1 formal charge.
Formal Charges
| Atom | Formal charge |
|---|---|
| N | +1 |
| double-bonded O | 0 |
| single-bonded O | -1 each |
Common Mistakes
- Do not draw nitrogen with more than eight electrons.
- Remember the brackets and overall negative charge for the ion.
FAQ
What is the Lewis structure for NO3-?
The NO3- Lewis structure has three equivalent resonance forms. In one form, nitrogen has one N=O double bond and two N-O single bonds; the single-bonded oxygen atoms carry -1 formal charge.
What is the Lewis dot structure for NO3-?
The Lewis dot structure for NO3- is the electron-dot drawing shown above. The NO3- Lewis structure has three equivalent resonance forms. In one form, nitrogen has one N=O double bond and two N-O single bonds; the single-bonded oxygen atoms carry -1 formal charge.
How many valence electrons does NO3- have?
NO3- has 24 total valence electrons in this Lewis structure.
What is the molecular geometry of NO3-?
NO3- has trigonal planar molecular geometry and trigonal planar electron geometry.
Is NO3- polar or nonpolar?
NO3- is an ion, so the overall charge matters more than a polar or nonpolar label. Its listed VSEPR shape is trigonal planar.
References
Method notes are aligned with standard Lewis structure steps: count valence electrons, draw a skeleton, distribute electrons, form multiple bonds when needed, and check formal charges and resonance.
OpenStax Chemistry 2e: Lewis Symbols and Structures and Formal Charges and Resonance.