Formal Charges and Valence Electrons in AlCl3

The video tutorial explains how to calculate the formal charge for each element in AlCl3 (aluminum chloride) using its Lewis structure. It details the process for chlorine, which is in group 17 with 7 valence electrons, and aluminum, which is in group 13 with 3 valence electrons. The tutorial emphasizes that the most favorable Lewis structure is achieved when the formal charges are zero, and warns against forming double bonds that would disrupt this balance.

What is the first step in determining the formal charge of an element in a compound?

• Count the total number of atoms.

• Measure the compound's mass.

• Use the Lewis structure and an equation.

• Identify the number of protons.

How many valence electrons does chlorine have in AlCl3?

• 8

• 5

• 6

• 7

What is the formal charge on chlorine in AlCl3?

• -1

• +2

• 0

• +1

Why is the formal charge on all chlorine atoms in AlCl3 the same?

• They are in different groups on the periodic table.

• They have different numbers of unbonded electrons.

• They have different numbers of bonded electrons.

• They are identical in the compound.

How many valence electrons does aluminum have in AlCl3?

• 2

• 3

• 5

• 4

What is the formal charge on aluminum in AlCl3?

• +1

• 0

• -1

• +2

Why is aluminum in AlCl3 an exception to the octet rule?

• It has more than eight electrons.

• It has fewer than eight electrons.

• It forms double bonds.

• It has a negative charge.

What happens to the formal charges if a double bond is formed between aluminum and chlorine in AlCl3?

• They are no longer zero.

• They remain zero.

• They become negative.

• They become positive.

Why is having zero formal charges important in determining the most favorable Lewis structure?

• It means the compound is ionic.

• It shows the compound is reactive.

• It suggests the compound is polar.

• It indicates maximum stability.

What is the most favorable Lewis structure for AlCl3 based on formal charges?

• One with mixed charges.

• One with zero formal charges.

• One with negative charges.

• One with positive charges.