Lewis Structures: Diagrams and Examples
A Lewis structure shows how valence electrons are shared in bonds or kept as lone pairs. Use the examples below to learn the method and check common molecular shapes.
Lewis structure examples
Choose a molecule to see its complete electron-dot structure, bond count and shape.
| Formula | Molecule | Key feature |
|---|---|---|
| CH4 | Methane | Four single bonds; tetrahedral shape. |
| H2O | Water | Two single bonds and two lone pairs; bent shape. |
| NH3 | Ammonia | Three single bonds and one lone pair; pyramidal shape. |
| N2 | Nitrogen | A triple bond and one lone pair on each nitrogen. |
| C2H4 | Ethene | A carbon–carbon double bond; trigonal planar around each carbon. |
| HOCl | Hypochlorous acid | H–O–Cl, with oxygen as the central atom. |
| CO2 | Carbon dioxide | Two C=O double bonds; linear shape. |
| XeF4 | Xenon tetrafluoride | Four bonds and two lone pairs; square planar shape. |
How to draw a Lewis structure
- Add the valence electrons from every atom. Adjust the total for any overall charge.
- Choose a central atom (usually the least electronegative one; hydrogen is never central) and connect the atoms with single bonds.
- Complete the outer shells of the surrounding atoms with lone pairs, then place any remaining electrons on the central atom.
- If the central atom lacks an octet, turn neighbouring lone pairs into double or triple bonds. Check the total electron count and formal charges.
Lewis structures are two-dimensional electron diagrams; they do not show a molecule’s full 3D geometry. Use the VSEPR chart to compare shapes, then build and rotate the molecule in the Molecule Builder.
Frequently asked questions
What is a Lewis structure?
A Lewis structure shows an atom’s valence electrons: shared pairs are drawn as bonds and unshared pairs as dots. It helps show how atoms are connected and whether each atom has a full outer shell.
How do you draw a Lewis structure?
Count the valence electrons, choose a central atom, connect atoms with single bonds, place the remaining electrons as lone pairs, then form multiple bonds if needed to complete outer shells and check formal charges.
How many electrons does a line represent in a Lewis structure?
One line represents one shared pair of electrons, so a single bond contains two electrons. A double bond has two shared pairs (four electrons), and a triple bond has three pairs (six electrons).
Where can I build a molecule in 3D?
Use the Molecule Builder to add atoms, form bonds and rotate the finished molecule.
