1
Parse the molecular formula and charge
NH4+ -> N, H, H, H, H; charge = +1
The ion contains one nitrogen atom, four hydrogen atoms, and an overall positive charge.
Lewis Structure
NH4+ Lewis Structure
Ammonium ion
NH4+ has nitrogen in the center with four N-H single bonds and no lone pairs on nitrogen.
Use the diagram and steps below to check the ammonium ion Lewis structure, NH4+ Lewis dot structure, valence electrons, formal charges, and molecular shape.
NH4+
Ammonium ion
Valence electrons8
Central atomN
GeometryTetrahedral
Bond angleAbout 109.5 deg
PolarityIon
Electron geometryTetrahedral
VSEPR Geometry
Molecular geometry
Tetrahedral
Electron geometry
Tetrahedral
Bond angle
About 109.5 deg
Polarity
Ion
Valence electrons
8
Bonding / lone pairs
4 / 0
Central atom
N
Electron regions
4
How to Draw NH4+: Step-by-Step
2
Count total valence electrons
5 + (4 x 1) - 1 = 8
Subtract one electron for the +1 ionic charge.
3
Choose the central atom
Central atom: N
Hydrogen cannot be central, so nitrogen goes in the center.
4
Draw the skeleton
Four N-H single bonds
The four bonds use all 8 available valence electrons.
5
Check the octet and charge
Formal charge on N = +1
Nitrogen has an octet, no lone pairs, and the ion has an overall +1 charge.
6
Final answer
The NH4+ Lewis structure has nitrogen in the center with four N-H single bonds and no lone pairs. Nitrogen has a +1 formal charge, giving the ion an overall +1 charge.
Formal Charges
| Atom | Formal charge |
|---|---|
| N | +1 |
| H | 0 each |
Common Mistakes
- Do not leave a lone pair on nitrogen in NH4+.
- The positive charge belongs to the whole ion, commonly shown on nitrogen in the Lewis drawing.
FAQ
What is the Lewis structure for NH4+?
The NH4+ Lewis structure has nitrogen in the center with four N-H single bonds and no lone pairs. Nitrogen has a +1 formal charge, giving the ion an overall +1 charge.
What is the Lewis dot structure for NH4+?
The Lewis dot structure for NH4+ is the electron-dot drawing shown above. The NH4+ Lewis structure has nitrogen in the center with four N-H single bonds and no lone pairs. Nitrogen has a +1 formal charge, giving the ion an overall +1 charge.
How many valence electrons does NH4+ have?
NH4+ has 8 total valence electrons in this Lewis structure.
What is the molecular geometry of NH4+?
NH4+ has tetrahedral molecular geometry and tetrahedral electron geometry.
Is NH4+ polar or nonpolar?
NH4+ is an ion, so the overall charge matters more than a polar or nonpolar label. Its listed VSEPR shape is tetrahedral.
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.