What You’ll Learn

Formal charge is a theoretical charge assigned to an atom within a molecule, assuming that electrons in all chemical bonds are shared equally, regardless of electronegativity differences. It is calculated using the formula FC=V - N - B/2​, where V is the number of valence electrons, N is the number of non-bonding electrons, and B is the number of electrons shared in bonds. Determining the formal charge helps in selecting the most stable Lewis structure for a molecule, as structures with formal charges closest to zero are generally preferred. Although formal charge does not represent the actual charge on an atom, it is a useful tool for predicting molecular structure and reactivity