ion if all of the bonding electrons were shared equally between atoms The formal charge is the "charge" an element would have in a molecule We can draw three inequivalent Lewis structures for carbon dioxide , CO2. The concepts of formal charge and electronegativity can help us choose the structure that is the best representation. 1. Assign formal charges to the elements in each of the structures below. 80,%3D - , Formal Charge C O2 2. The best Lewis structure for CO, is