What is the Lewis structure of acetone?

The Lewis structure of acetone is composed of two methyl groups single-bonded to a carbon atom, which is also double-bonded to an oxygen atom. The oxygen atom is the only atom that does not share all of its electrons, resulting in two lone pairs.

The number of valence electrons an atom has helps determine the Lewis structure of a molecule. Carbon has four valance electrons, oxygen has six and hydrogen has one. The oxygen shares electrons with carbon through double bonds, accounting for two of oxygen's valence electrons; the other four are accounted for through lone pairs. Acetone is also an achiral molecule, meaning that its mirror image is superimposable upon itself.