Lewis Structure Generator
Acetaldehyde · CH₃CHO

CH₃CHO Lewis Structure

The terminal carbonyl carbon is bonded to hydrogen, distinguishing an aldehyde from a ketone.

Open CH₃CHO in the generatorSee drawing steps
CH₃CHO
CH₃—C(=O)—H
Reviewed stored connectivity; detailed electron placement is explained below
Total valence electrons18
Reviewed connectivityCH₃—C(=O)—H
GeometryTrigonal planar at the carbonyl carbon
Support levelReviewed guide

Acetaldehyde overview

The stored Lewis connectivity is CH₃—C(=O)—H. The terminal carbonyl carbon is bonded to hydrogen, distinguishing an aldehyde from a ketone.

How to draw CH₃CHO

  1. Count 18 valence electrons. Include charge adjustments before drawing.
  2. Use the reviewed connectivity CH₃—C(=O)—H. Do not infer a different isomer from the formula alone.
  3. Place the required single, double or multiple bonds. Keep a running electron total.
  4. Complete terminal valence shells and add lone pairs or formal charges. The terminal carbonyl carbon is bonded to hydrogen, distinguishing an aldehyde from a ketone.
  5. Verify the total electron count and geometry. The reviewed geometry is Trigonal planar at the carbonyl carbon.

Why this example matters

The terminal carbonyl carbon is bonded to hydrogen, distinguishing an aldehyde from a ketone.

Scope and model limits

The condensed display groups the methyl C–H bonds while showing the carbonyl and aldehydic hydrogen explicitly.

Common mistakes

  • Drawing acetone instead
  • Using a C–O single bond only
  • Omitting oxygen lone pairs

Last reviewed: 2026-07-16. Educational reference only; verify graded work with course materials.