Formal Charge in Carbon Tetrachloride (CCl4)

Q: Determine the formal charge of the least electronegative element in the following molecule: Carbon tetrachloride (CCl4)

Background

Topic: Formal Charge and Electronegativity

This question tests your understanding of how to assign formal charges in a molecule and how to identify the least electronegative atom.

Key Terms and Formulas

• Formal Charge: The charge assigned to an atom in a molecule, assuming equal sharing of electrons in bonds.

• Electronegativity: The tendency of an atom to attract electrons. The least electronegative element is typically found in the center of the molecule.

Formal Charge Formula:

$\text{Formal Charge} = \text{Valence Electrons} - \text{Nonbonding Electrons} - \frac{1}{2} \times \text{Bonding Electrons}$

Step-by-Step Guidance

1. Identify the least electronegative element in CCl4. Chlorine is more electronegative than carbon, so carbon is the least electronegative atom.

2. Draw the Lewis structure for CCl4. Carbon is in the center with four chlorine atoms bonded to it, and each chlorine has three lone pairs.

3. Count the valence electrons for carbon (4) and determine the number of nonbonding electrons (carbon has none in CCl4).

4. Count the bonding electrons around carbon (each C–Cl bond has 2 electrons, so 4 bonds × 2 = 8 electrons).

Try solving on your own before revealing the answer!