Which of the following statements correctly describes formal charge?

• A. Formal charge indicates the actual charge on an atom in a molecule.
• B. Formal charge is calculated by subtracting the number of nonbonding electrons and half the number of bonding electrons from the number of valence electrons in the free atom.
• C. Formal charge is always zero for every atom in a neutral molecule.
• D. Formal charge is the same as the oxidation number for all atoms in a molecule.

Answer: (B)

Verified step by step guidance

1. Understand that formal charge is a bookkeeping tool used in chemistry to estimate the distribution of electrons in a molecule, not the actual charge on an atom.
2. Recall the formula for calculating formal charge: \(\text{Formal Charge} = \text{Valence Electrons} - \text{Nonbonding Electrons} - \frac{1}{2} \times \text{Bonding Electrons}\), where valence electrons are those in the free atom.
3. Recognize that formal charge helps determine the most stable Lewis structure by minimizing charges, but it does not necessarily equal the actual charge on the atom in the molecule.
4. Note that formal charge can be zero, positive, or negative, and it is not always zero for every atom in a neutral molecule.
5. Understand that formal charge is different from oxidation number; oxidation number is a different concept based on electron counting rules related to electronegativity.