Formal Charge and Bonding Pairs

The video tutorial explains how to calculate the formal charge of atoms in molecules using the formula: valence electrons minus the sum of bonding and lone pairs. It provides examples with PCl3, ammonium ion, and carbon dioxide, demonstrating the step-by-step calculation of formal charges for each atom in these molecules. The tutorial concludes with an exercise for students to practice the concept.

What is the formula for calculating formal charge?

• Valence electrons minus bonding pairs

• Valence electrons minus the sum of bonding and lone pairs

• Valence electrons minus lone pairs

• Valence electrons minus the sum of bonding pairs

In the PCl3 example, what is the formal charge of phosphorus?

• +2

• 0

• -1

• +1

How many lone pairs does chlorine have in PCl3?

• Six

• Four

• Eight

• Two

What is the formal charge of nitrogen in the ammonium ion?

• 0

• +1

• +2

• -1

How many bonding pairs does nitrogen have in the ammonium ion?

• Three

• Four

• Two

• Five

What is the formal charge of hydrogen in the ammonium ion?

• +1

• 0

• -1

• +2

In carbon dioxide, what is the formal charge of carbon?

• +2

• 0

• -1

• +1

How many bonding pairs does oxygen have in carbon dioxide?

• Three

• Two

• One

• Four

What is the formal charge of oxygen in carbon dioxide?

• +2

• 0

• -1

• +1

What should students do if they have questions about the exercise?

• Ask a classmate

• Email the teacher

• Submit questions online

• Visit the teacher in person