How are covalent electron dot structures, or Lewis structures, drawn? How do you know when there is a single bond or a double bond? How do you know when there are lone pairs? Follow these next steps to successfully draw covalent electron dot structures.

First, use the periodic table to help.

Now, let’s draw the covalent electron dot structures for formaldehyde. The chemical formula for formaldehyde is CH2O.

Interactive exercise. Assistance may be required. Click on the Next button to begin the interactive.

Video segment. Assistance may be required. Watch the following video to see how to draw the covalent electron dot structure for phosphorous trichloride, PCl3.

Source: PCl3 Lewis Structure - How to Draw the Lewis Structure for PCl3, Wayne Breslyn, YouTube

What was different about the structure drawn in this video versus the structure drawn in the interactive?

Interactive popup. Assistance may be required.

Check Your Answer

In this structure, the central atom, phosphorus, had a lone pair of electrons. Close Pop Up