Draw Lewis dot structures for molecules. Automatically count valence electrons, assign formal charges, and show resonance structures.
Specify a molecule and its bonding arrangement, and the drawer turns the electron bookkeeping into a Lewis dot diagram. Bonds represent shared electron pairs, dots represent lone pairs, the valence-electron total is tallied, and formal charges are assigned to individual atoms. When more than one valid electron placement shares the same atomic framework, the result can include resonance contributors. The point most often misread is that those contributors are not separate molecules switching back and forth; they are alternative drawings of one delocalized electronic structure.
A concrete input and expected output from the current implementation.
Input
CH4
Expected output
A central C joined to four H atoms by single bonds. Total valence electrons: 8. Lone pairs: none. Formal charge: 0 on C and 0 on each H.
Carbon contributes 4 valence electrons and the four hydrogens contribute 4, giving 8. The four bonds contain four shared pairs, using all 8 electrons; formal charge is 4 - 0 - 4 = 0 for carbon and 1 - 0 - 1 = 0 for each hydrogen.
The displayed total is the electron budget for the entered species. It sums the atoms' valence electrons and includes any stated net charge in the balance. A single bond represents one shared pair, while double and triple bonds represent two and three pairs. The drawn bonds and lone-pair dots should account for the reported total.
For each atom, formal charge equals its valence-electron count minus its nonbonding electrons minus half its bonding electrons. The drawer reports these atom-by-atom assignments and can show resonance contributors that retain the same atom connectivity while moving electrons. Contributors need not be equally important, and formal charges are bookkeeping values rather than measured partial atomic charges.
No. When only electron placement changes while the nuclei and atom connectivity remain fixed, the drawings are resonance contributors to one species. The electron distribution is not usually represented by selecting one contributor or imagining a timed flip between them. Use the displayed set to compare electron placement and formal charge, not to count isolable compounds.
No. Small formal charges and limited charge separation are useful preferences, but they do not override the electron total, known connectivity, or element-specific bonding behavior. Equivalent resonance contributors may have equal roles, and some species cannot be represented adequately by one Lewis drawing. Treat the charge labels as a consistency check, not proof of the complete electronic structure.
The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.
Calculate percentages, percentage change, and what percent one number is of another with step-by-step breakdowns.
Calculate tips and split bills between multiple people with customizable tip percentages and rounding options.
Calculate monthly payments, total interest, and generate amortization schedules for loans and mortgages.
Calculate Body Mass Index from height and weight with category classification and healthy range guidance.
Calculate sale prices, savings amounts, and final costs after single or stacked percentage discounts.
Compute mean, median, mode, standard deviation, variance, and other descriptive statistics from a data set.