Lewis Structures and Formal Charges

The video tutorial explains the Lewis structure of H2CO3, carbonic acid. It begins by calculating the total valence electrons and arranging the atoms with carbon at the center. The tutorial demonstrates forming chemical bonds and achieving octets for each atom. It addresses the need for a double bond to complete the octet for carbon and checks the formal charges to ensure the structure's accuracy. The video concludes with a complete and correct Lewis structure for H2CO3.

How many total valence electrons are present in H2CO3?

• 18

• 20

• 24

• 26

Where should the hydrogen atoms be placed in the Lewis structure of H2CO3?

• Attached to the outer oxygen atoms

• Attached to the carbon atom

• Attached to the central oxygen atom

• Floating freely

What is the purpose of placing two electrons between atoms in the Lewis structure?

• To stabilize the molecule

• To create a magnetic field

• To increase the number of valence electrons

• To form chemical bonds

Why does carbon need additional electrons in the Lewis structure of H2CO3?

• To achieve a full outer shell

• To bond with hydrogen

• To become positively charged

• To increase its atomic number

How is the octet rule satisfied for carbon in H2CO3?

• By removing electrons from oxygen

• By sharing electrons in a double bond with oxygen

• By forming a triple bond with oxygen

• By adding more hydrogen atoms

What is the formal charge of each atom in the final Lewis structure of H2CO3?

• 0

• +2

• -1

• +1

What is the significance of having a formal charge of 0 for each atom in H2CO3?

• It indicates the molecule is unstable

• It confirms the correct Lewis structure

• It shows the molecule is an ion

• It suggests the molecule is radioactive

What is the role of Dr. B. in the video?

• He is a student asking questions

• He is a guest lecturer

• He is the narrator explaining the Lewis structure

• He is a chemist conducting experiments