Question

The correct formula used to determine the formal charge (\( Q_f \)) on an atom in the given Lewis structure of a molecule or ion is (V = number of valence electrons in free atom, U = number of unshared electrons on the atom, B = number of bonds around the atom)

• A. \( Q_f = V - \left( \frac{U}{B} \right) \)
• B. \( Q_f = V + (U - B) \)
• C. \( Q_f = V - (U + B) \)
• D. \( Q_f = V - \left( \frac{B}{U} \right) \)

Hint:

Formal charge helps predict the most stable Lewis structure of a molecule.

Answer 1

The Correct Option is C

The formal charge formula is: \[ Q_f = V - (U + B) \] where:
- \( V \) = Number of valence electrons in a free atom.
- \( U \) = Number of unshared (lone pair) electrons.
- \( B \) = Number of bonds formed by the atom.
This formula is used to determine the charge on atoms in Lewis structures to understand molecular stability.
Thus, the correct answer is: \[ \boxed{Q_f = V - (U + B)} \]