Valence Electrons and Lewis Structures

The video tutorial explains how to write the Lewis structure for the AlBr4- ion. It begins by counting the total valence electrons, considering aluminum and bromine's positions in the periodic table, and accounting for the negative charge. The tutorial then describes placing the least electronegative element, aluminum, at the center and arranging bromine atoms around it. Electrons are placed between atoms to form bonds, and the octets of the bromine atoms and the central aluminum are completed. The final structure is enclosed in brackets with a negative sign to indicate the ion.

How many valence electrons does aluminum contribute to the AlBr4- ion?

• 5

• 7

• 1

• 3

What is the total number of valence electrons in the AlBr4- ion?

• 34

• 32

• 30

• 28

Which element is placed at the center of the AlBr4- Lewis structure?

• Fluorine

• Chlorine

• Aluminum

• Bromine

How many bromine atoms are arranged around the central aluminum atom in AlBr4-?

• 4

• 3

• 2

• 5

What is the purpose of placing electrons between aluminum and bromine atoms in the Lewis structure?

• To form covalent bonds

• To increase electronegativity

• To form ionic bonds

• To balance the charge

How many valence electrons are used to complete the octets of the bromine atoms?

• 8

• 24

• 32

• 16

What should be added to the Lewis structure of AlBr4- to indicate it is an ion?

• A positive sign

• A negative sign

• Both brackets and a negative sign

• Brackets

What is the final step in completing the Lewis structure for AlBr4-?

• Placing brackets and a negative sign

• Ensuring all atoms have octets

• Removing electrons

• Adding more electrons