Lewis structures, worked step by step
Each molecule is worked through the same five steps: count the valence electrons, draw the Lewis structure, read off the VSEPR shape, decide whether it is polar, and add up the molar mass one atom at a time. Every looked-up number links to NIST or PubChem; every number this site works out itself is marked as calculated.
Molecules worked so far
Every page uses the same five-step method; the shape and polarity columns show where each molecule's geometry gives a different contrast.
| Molecule | Shape | Polarity |
|---|---|---|
| CO2 carbon dioxide | linear | nonpolar |
| H2O water | bent | polar |
What each page has
- Valence electron count for every atom, and the total.
- A Lewis structure diagram drawn from coordinates, with lone pairs and any formal charges shown.
- The VSEPR electron-domain shape and a labelled bond angle, worked out from the structure.
- Whether the molecule is polar, from the electronegativity difference of each bond and the molecule's symmetry.
- The molar mass, added up atom by atom from NIST's standard atomic weights.
Read how the numbers are checked before relying on them.