Formal Charges Flashcards
Formal Charge
Charge that would reside on the atom if all of the bonding electrons were shared equally.
How to calculate formal charge of an atom?
Formal Charge = valence electrons - associated electrons.
How to know valence electrons?
The atom’s group number
How to calculate associated electrons?
Number of lone pair electrons + 1/2 number of bonding electrons.
A molecular structure in which all formal charges are what?
Zero
If the Lewis Structure have nonzero formal charges, what should you do?
The arrangement with the smallest nonzero formal charges is preferable.
Lewis structures are preferable when they are what?
Adjacent formal charges are zero or of the opposite sign.
When choosing among several Lewis structures with similar distributions of formal charges, what is the most preferable?
Structures with negative formal charges on the more electronegative atoms is preferable.
