Valence Electrons and Lewis Structures

This video tutorial explains how to write the Lewis structure for HPO4 2-. It begins by counting the valence electrons, placing phosphorus in the center, and arranging the oxygen atoms around it. The tutorial covers completing octets, checking formal charges, and making necessary adjustments by forming a double bond to achieve a more stable structure. The video concludes with finalizing the structure by adding brackets and a charge notation.

How many total valence electrons are there in the HPO4 2- ion?

• 36

• 34

• 32

• 30

What does the presence of hydrogen in front of a polyatomic ion typically indicate?

• It is a base.

• It is a salt.

• It is neutral.

• It is an acid.

Where is the hydrogen atom attached in the HPO4 2- structure?

• To the nitrogen atom

• To the central atom

• To one of the oxygen atoms

• To the phosphorus atom

How many valence electrons are used to form chemical bonds initially in the HPO4 2- structure?

• 12

• 8

• 14

• 10

What is the purpose of checking formal charges in a Lewis structure?

• To increase the number of bonds

• To minimize the charges and make the structure more stable

• To make the structure symmetrical

• To ensure the structure is colorful

What modification is made to the HPO4 2- structure to improve formal charges?

• Forming a double bond with phosphorus

• Removing an oxygen atom

• Adding more electrons

• Adding more hydrogen atoms

What is the formal charge on phosphorus after forming a double bond in the HPO4 2- structure?

• -1

• +1

• 0

• +2

Why is it important to put brackets around the final Lewis structure of HPO4 2-?

• To make it look neat

• To separate it from other structures

• To show it is an ion with a charge

• To indicate it is a molecule

What is the charge outside the brackets in the final Lewis structure of HPO4 2-?

• +1

• -1

• -2

• +2

What is the significance of the double bond in the HPO4 2- structure?

• It adds more hydrogen atoms

• It decreases the stability of the structure

• It helps achieve zero formal charges on certain atoms

• It increases the number of valence electrons