Valence Electrons and Formal Charges

Dr. B explains the process of drawing the Lewis structure for POCl3. Starting with the valence electrons for each atom, the video guides through placing atoms, forming bonds, and ensuring each atom satisfies the octet rule. The initial structure is evaluated for formal charges, revealing a need for improvement. By forming a double bond between phosphorus and oxygen, the structure is optimized, resulting in zero formal charges and increased stability. The video concludes with a summary of the improved structure.

How many valence electrons are present in the POCl3 molecule?

• 30

• 28

• 34

• 32

Which atom is placed at the center of the POCl3 structure?

• Hydrogen

• Phosphorus

• Chlorine

• Oxygen

How many valence electrons are used in forming the initial bonds in POCl3?

• 8

• 12

• 10

• 6

What is the formal charge on Phosphorus before adjusting the structure?

• +1

• +2

• 0

• -1

What is the formal charge on Oxygen before forming the double bond?

• +1

• 0

• -1

• +2

What adjustment is made to the POCl3 structure to achieve zero formal charges?

• Changing the central atom

• Removing a bond

• Forming a double bond

• Adding more electrons

What is the formal charge on each atom after forming the double bond in POCl3?

• +2

• 0

• +1

• -1

Why is the adjusted POCl3 structure more stable?

• It has more electrons

• It has zero formal charges

• It has a different central atom

• It has fewer bonds

Which element in POCl3 can have more than eight valence electrons?

• Oxygen

• Chlorine

• Phosphorus

• Hydrogen

What is the significance of achieving zero formal charges in a Lewis structure?

• Increases reactivity

• Decreases stability

• Decreases reactivity

• Increases stability