A Chemically Intuitive Procedure for Drawing Lewis Structures

Lewis structures are an important concept in introductory and general chemistry. It is well known that the octet rule leads to non-preferred Lewis structures for many chemical species. Less recognized is that the formal charge calculations, which is the prevailing approach in chemical education for drawing Lewis structures, also fails to give the preferred Lewis structures for some common compounds. Described here is a chemically intuitive procedure for drawing Lewis structures, which resembles a valence bond theory treatment. The electron assignments are based on electronegativity and the octet rule. This procedure may help students to more readily draw the most probable Lewis structures including those that do not adhere to the application of formal charges in determining the most probable structures.