Lewis Dot Structure Generator: Lone Pairs
This Lewis dot structure generator draws the Lewis structure of small molecules and ions that have one central atom. Type a formula such as H2O, CO2, NH3, NH4+, SO4^2-, PCl5 or XeF4 and it counts the valence electrons, picks the central atom, connects the outer atoms with single bonds, fills octets with lone pairs, and forms double or triple bonds where the central atom needs them. Period 3 and heavier atoms can take an expanded octet to lower formal charges. The drawing shows every bond and lone pair, with formal charges in red, and the table lists the electron geometry, molecular shape and bond angle from VSEPR theory.
Lewis Dot Structure Generator
Draw the Lewis structure of a molecule or ion with bonds, lone pairs, formal charges and VSEPR shape.
How to use the Lewis Dot Structure Generator
- Type a formula, like CO2, or tap an example.
- Add a charge at the end for ions, like NO3- or SO4^2-.
- Look at the drawing of bonds and lone pairs.
- Read the shape, bond angle and formal charges.
Features
- Molecules and ions with one central atom
- Double and triple bonds
- Formal charges and expanded octets
- Radicals and electron-poor exceptions like BF3
- VSEPR shape and bond angle
Frequently asked questions
How do you draw a Lewis dot structure?
Count the valence electrons, put the least electronegative atom in the center, connect each outer atom with a single bond, give the outer atoms full octets, put leftover electrons on the center atom, and form multiple bonds if the center still lacks an octet.
How many valence electrons does CO2 have?
Carbon has 4 and each oxygen has 6, so 4 + 6 + 6 = 16. The structure is O=C=O with two lone pairs on each oxygen.
How do charges change the electron count?
Add one electron for each negative charge and remove one for each positive charge. NH4+ has 5 + 4 − 1 = 8 valence electrons.
What is a formal charge?
Formal charge = valence electrons − lone-pair electrons − bonds. The best Lewis structure keeps formal charges as close to zero as possible.
Why can sulfur have more than 8 electrons?
Atoms in period 3 and below, such as P, S, Cl and Xe, can hold more than an octet. That is how PCl5 and SF6 have 10 and 12 electrons around the center.