formal charge

[Aashka Popat 1A]

What exactly is formal charge and why does it help us find lower energy structures?

[Abigail Menchaca_1H]

formal charge just keeps track of the electrons and whether they are being given away(+) or gained (-)

[Ashley Fang 2G]

It can be calculated through FC = [# of valence electrons on atom] – [(# of lone pair electrons) + (# of shared electrons)/2]

[christabellej 1F]

Formal charge can also help you predict which structure is the lowest energy structure (and thus which structure contributes more to the hybrid) as the closer the formal charges are to 0 on the atoms gives you the lowest energy structure.

[serenabirkhoff_1K]

FC = [# of valence electrons on atom] – [(# of lone pair electrons) + (# of shared electrons)/2]

Formal charge helps you predict which structure is the lowest energy structure. The closer the formal charges are to 0 on the atoms the lower the energy of the structure.
It is important to calculate formal charge when writing Lewis structures to ensure that the answer you give has the lowest energy level possible, especially if there are resonance structures.