Chapter 5

Question 1

What does it mean for the total number of orbitals to be conserved?

Answer 1

You have the same number of MOs as the number of AOs you started with

Question 2

A molecule is stable when the MOs have lower energy than the AOs.

Answer 2

True

Question 3

What rule do we use to fill MOs?

Answer 3

Aufbau principle, same as AOs

Question 4

Relative to symmetry, describe a sigma bond (and sigma*)

Answer 4

No change of sign upon rotation on z-axis (C2).

Sigma is gerade; sigma* is ungerade

Question 5

Relative to symmetry, describe a pi bond (and pi*)

Answer 5

Change of sign upon C2 rotation.

Pi is ungerade; pi* is gerade

Question 6

Relative to symmetry, describe a delta bond

Answer 6

Change of sign upon C4 rotation (90º)

Question 7

Strong interaction means more stabilization energy.

Answer 7

True; like in covalent diatoms

Question 8

Bond order equation

Answer 8

1/2(# bonding electrons - # antibonding electrons)
OR
binding orbitals - antibonding orbitals

Question 9

More electronegative atoms have AOs on lower levels

Answer 9

True; so the atoms contributing the most to the bonding are the ones less electronegative (like C in CO)

Question 10

The sigma goes back to being below the pi starting from O forward (just 2nd row).

Answer 10

True

Question 11

How can we measure the energy of MOs?

Answer 11

Photoelectron Spectroscopy (also AOs)

Question 12

The lower the orbital is the more energy it takes to remove electrons from it.

Answer 12

True