Lewis Structures and Valence Electrons

This video tutorial covers exceptions to Lewis structure rules, focusing on odd electron species like nitrogen monoxide and the concept of free radicals. It also explains how to expand the octet using d orbitals, with an example of phosphorus pentachloride. The tutorial emphasizes understanding formal charges and the stability of molecules with expanded octets.

Which element is most commonly associated with having an odd electron in its Lewis structure?

• Carbon

• Oxygen

• Hydrogen

• Nitrogen

In the Lewis structure of nitrogen monoxide, what is the term used for the unpaired electron?

• Lone pair

• Free radical

• Ionic bond

• Covalent bond

What is the formal charge on nitrogen in the nitrogen monoxide molecule?

• +1

• 0

• +2

• -1

What is the significance of d orbitals in expanding the octet?

• They allow for more than 8 electrons around an atom.

• They reduce the number of electrons needed.

• They are irrelevant in Lewis structures.

• They are only used in ionic bonds.

Which molecule is used as an example to explain the expansion of the octet?

• NH3

• CO2

• H2O

• PCl5

How many valence electrons does phosphorus have in the PCl5 molecule?

• 9

• 7

• 5

• 3

In the PCl5 molecule, how many electrons are around phosphorus?

• 10

• 8

• 14

• 12

What is the formal charge on phosphorus in the PCl5 Lewis structure?

• 0

• +2

• -1

• +1

How many chlorine atoms are bonded to phosphorus in PCl5?

• 3

• 4

• 5

• 6

What is the total number of electrons in the PCl5 molecule?

• 45

• 35

• 30

• 40