A model pioneered by Gilbert N. Lewis and Irving Langmuir that represents the electronic structure of a molecule by writing the valence electrons of atoms as dots.
Pairs of dots (or lines) wedged between atoms represent bonds; dots drawn elsewhere represent nonbonding electrons.
In a Lewis structure, usually the atom that is the most electronegative.
In Lewis structures the goal is to make almost all atoms have an octet. This means that they will have access to 8 electrons regularly, even if they do have to share some of them.