Follow these steps when drawing a Lewis structure of a molecule:
- Arrange bonded atoms symmetrically around the central atom.
- Count the total number of valence electrons (including an ion’s charge).
- Place a bonding pair of electrons between the central atom and each atom surrounding it.
- Complete the octets of surrounding atoms with lone pairs, and, if the total number of electrons is not yet reached, add lone pairs to the central atom.
- If the central atom doesn’t have an octet, move pairs from bonded atoms to form double bonds or triple bonds.
- Draw the final Lewis structure. If it is a polyatomic ion, enclose it in square brackets and indicate the charge with a superscript.