The formal charge is the "charge" an element would have in a molecule or ion if all of the bonding electrons were shared equally between atoms. We can draw three inequivalent Lewis structures for the thiocyanate ion , SCN- . 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. ABCFormal ChargeSCN-12010-100-12. The best Lewis structure for SCN- is .