Which of these statements correctly describes the use of formal charge in choosing between possible Lewis structures to describe a molecule?
I. Formal charge on all the atoms should be zero, or at least the smallest possible value.
II. The sum of the formal charges on all the atoms should equal the charge on the molecule or ion.
III. The formal charge on an atom is not affected by the electronegativity of the atom.
IV. In an anion containing nitrogen and oxygen, the Lewis structures with a negative charge on the nitrogen will contribute the most to the description of the bonding.

Question

Quizplus · Accepted Answer

I is correct because the Lewis structure with formal charges closest to zero is usually the most stable.
II is correct because if the sum of the formal charges does not equal the charge on the molecule or ion, then the Lewis structure is not a valid representation of the bonding.
III is incorrect because the electronegativity of an atom does affect its formal charge. 
IV is incorrect because the placement of a negative charge on the nitrogen or oxygen can depend on factors such as electronegativity and resonance structures.

Which of These Statements Correctly Describes the Use of Formal