Test 1 (9/02)
PHYS 0201
(Organic)
Name______________________
1. a. (8 pts.) Draw an energy level diagram for the valence electrons of a normal C atom.
2p
2s
b. (2 pts.) Draw an energy level diagram for the valence electrons of an sp3 hybridized C atom.
sp3
2. (2.5 pts. each) For each pair of molecules, identify the stronger acid.
a.
b.
NH3
PH3
HBF4
this one
this one
c.
c.
F
H
H
C
C
C
O
C
C
C
H
C
O
H
H
H
C
C
C
H
H
C
C
H
H
O
O
C
H3C
C
O
HF
O
S
H3C
S
OH
H
OH
O
this one
this one
3. (2.5 pts. each) For each pair of molecules, identify the stronger base.
a.
b.
H2S
H2O
CH3–
this one
this one
c.
d.
PH3
this one
Br–
O
PCl3
H3C
O
C
Cl3C
C
O
O
this one
4. Determine the hybridization of the indicated atoms in the following molecules. The following
molecules are not complete Lewis structures. Each atom has the correct number of bonds, but
some atoms need to have lone pairs of electrons added to them.
a.
b.
c.
H
H
H
O
N
C
C
H
C
H
H
H
O
N sp3, O sp2, C sp2
H
H
C
H
H
C
H
C
C sp, N sp2
N
H
H
C
H
S
C
N
S sp3, C sp, N sp
5. Identify the polar molecules. The following molecules are not complete Lewis structures. Each
atom has the correct number of bonds, but some atoms need to have lone pairs of electrons added
to them.
a.
b.
c.
d.
H
H
O
C
N
H
O
polar
H
H
O
H
C
C
C
H
e.
polar
H
H
F
C
C
F
H
H
H
H
C
C
C
C
Cl
H
Cl
Cl
polar
f.
H
Cl
polar
g.
Cl
Cl
H
H
C
C
C
H
H
H
non-polar
polar
H
h.
H
H
H
H
C
C
C
F
H
F
S
C
S
H
H
H
F
C
C
C
H
F
H
non-polar
g.
H
polar
i.
F
S
F
polar
non-polar
6. Draw Lewis structures for the following molecules. Include formal charges where appropriate.
a. CH3S(O)CH3
b. (CH3)2CHCHNH
••
H
C
S
C
H
H
or
H
•• O ••
H
C
S
C
H
H
H
H
H
H
H
C
C
C
H H
C
N
H
••
•• O ••
••
H
H
H
H
H
H
c. (CH3)2CH(CH2)3SCH3
d. CH3C(O)NCH2CH3
typo cannot do
H
H
H
H
C
C
C
C
C
H H
C
H H
H
H
H
••
H
H
S
C
H
••
H
H
7. Draw the shapes for the following molecules.
a.
b.
CH2=C=NH
H
H
C
H
c.
HCBrClF
C
N
or
H
F
C
H
C
N
H
C
H
CH3OCH3
H
Br
Cl
O
C
C
H H
H
H
H
H
8. If a p-bond is weaker than a s-bond, why is a double bond stronger than a single bond?
Because a double bond is made of a s- + a p-bond, not just a p-bond.
9. Describe (name) the orbitals on the C and O atoms used to form the C to O bonds in H2C=O.
The s-bond is formed with an sp2 hybrid from the C and an sp2 hybrid from the O. The p-bond is formed
from the leftover p orbital on the C and the leftover p orbital on the O.
10. Ozone is O3. Draw the two resonance forms for the O3 molecule. Include formal charges where
appropriate. Remember, none of the atoms move when different resonance forms are drawn. The
Lewis structure for O3 is very similar to the Lewis structure for NO2–, which we drew in class.
••
O••
••
O
••
••
••
O
••
••
O
••
••
••
O
O
••