CHM2045 Exam 3

What kind of bonding?

Sigma

What kind of bonding?

Pi

Bond order?

Double bond

Bond order?

Triple bond

Four principles of MO theory

What does adding wave functions produce?

A bonding MO; constructive interference

What does constructive interference do?

Promotes bonding

What does subtracting wave functions produce?

Antibonding MO; destructive interference

What does destructive interference do?

Decreases bonding

How do you rank the stability of MO bonds?

Highest bond order > lowest bond order

MO bond order

½ (# e- in bonding orbitals - # e- in antibonding orbitals

Why doesn’t He2 exist?

Bond order = 0

What does unstable mean?

Bond order = 0; does not exist

How does number of bonding e- vs. antibonding e- affect bonds?

More bonding vs. nonbonding = stronger bonds

Paramagnetic

Electrons not paired

Diamagnetic

Electrons paired

Why does Ne exist as a monoatomic gas?

MO bond order

Benzene formula

C6H6

Why is resonance not needed in MO theory?

Electrons delocalized amongst bonds

AX2 molecular geometry

linear

AX3 molecular geometry

trigonal planar

AX2E1 molecular geometry

bent

AX4 molecular geometry

tetrahedral

AX3E1 molecular geometry

trigonal pyramidal

AX2E2 molecular geometry

bent

AX5 molecular geometry

trigonal bipyramidal

AX4E1 molecular geometry

seesaw

AX3E2 molecular geometry

t shaped

AX2E3 molecular geometry

linear

AX6 molecular geometry

octahedral

AX5E1 molecular geometry

square pyramidal

AX4E2 molecular geometry

square planar

AX3E3 molecular geometry

t shaped

AX2E4 molecular geometry

linear

Are lone pairs equatorial or axial?

Equatorial

In Cl2CO, what direction is the overall dipole?

Toward the O

A liquid boils when…

its vapor pressure equals the external pressure. (use for Clausius-Clapeyron equation)