Lecture 5 (MO Theory) Flashcards
What is MO Theory?
Allocation of electrons to molecular orbitals formed by the overlap of atomic orbitals
What are the conditions for MO Theory?
1) symmetry of atomic orbitals are compatible
2) region of overlap between atomic orbitals are significant
3) atomic orbitals are close in energy
The number of MO’s formed are equal to the number of atomic orbitals of the constituent atoms. True or False?
True
How are MO’s populated?
they are populated with electrons, in order of energy, from lowest to highest
What kind of interaction occurs when atomic orbitals are in-phase?
bonding interaction
What kind of interaction occurs when atomic orbitals are out-of-phase?
anti-bonding (denoted with *)
What is bonding interactions?
formation of bonding MO’s when occupied with electrons, stabilize the molecule.
What is anti-bonding interactions?
formation of anti-bonding MO’s when occupied with electrons, destabilize the molecule
What indicates the parity of the MO’s?
g and u (gerade and ungerade)
What is gerade mean?
“even”, indicates the orbital has a center of symmetry
What does ungerade mean?
“odd”, indicates the orbital does not have a center of symmetry
What is the Bond Order equation?
BO=1/2(#bonding e - #antibonding e)
what is the trend of effective nuclear charge?
increases from B to F
We know 2s orbitals are more penetrating than 2p. What does this cause with energy and nuclear charge?
The energy decreases due to the increased nuclear charge
