1. Factors which influence the strength of the interactions between two atomic orbitals which produce 2 molecular orbitals is determined by:
A. the energy difference between the orbitals.
B. the magnitude of their overlap.
In general…for the interaction to be strong…the energies of the orbitals must be ~ equal and the overlap should be large.
Li2
Liatom 1s22s1
Liatom 1s22s1

2. stable molecule Li2 s1s2 s1s*2 s2s2 E Liatom 1s22s1 Liatom 1s22s1 s2s*
Bond Order 1s 1s
= 1
s1s
Li2
Liatom 1s22s1
Liatom 1s22s1

3. All scientific models are perfect and in no need of modifications?
Which of the following concepts would you associate with atomic orbitals?
delocalized electrons or localized electrons
3. What type of orbitals would you associate with delocalized electrons?
4. When two atomic orbitals combine to give a set of molecular orbitals, the M.O.’s are differentiated from each other by what designation?
5. When molecular orbitals are symmetrical about the axis between two nuclei we call them by what designation?
6. Molecular orbitals, when being filled, follow the same rules as filling atomic orbitals…they are?

4. B2
Batom 1s22s22p1
Batom 1s22s22p1

5. stable molecule B2 all electrons are paired!!! E Batom 2s22p1
Diamagnetic
p2p*
p2p* 2p
p2p
p2p 2p E
s2p
s2s*
Bond Order 2s 2s
= 1
s2s B2
Batom 2s22p1
Batom 2s22p1

6. stable molecule B2 two electrons are unpaired!!! E Batom 2s22p1
Paramagnetic
s2p*
p2p*
p2p* 2p 2p
s2p E
p2p
p2p
s2s*
Bond Order 2s 2s
= 1
s2s B2
Batom 2s22p1
Batom 2s22p1

7. C2 N2 O2 CN- s2p* p2p* p2p s2p s2p p2p s2s* s2s 2 3 2 3 dia dia para
B.O.→
New filling order to to s-p mixing C2 N2 O2
CN-
s2p*
p2p* E
p2p
s2p
s2p
p2p
s2s*
s2s
dia
dia
para
dia
Magnetism?→