Chem201A
Dr. Baxley
Geometries and Valence Bond Theory Worksheet
Also do Chapter 10 textbook problems: 33, 35, 47, 49, 51, 55, 57, 61, 63, 67, 83, 87.
1. Fill in the tables below for each of the species shown.
a) CCl2H2
Lewis Structure, complete with formal charges
(show any possible resonance structures too!)
Molecular Geometry:
Bond Angle(s):
Polar or not?
Hybridization
Orbital Diagram of central atom alone
Orbital Diagram of central atom in compound
b) ClNO
Lewis Structure, complete with formal charges
(show any possible resonance structures too!)
Molecular Geometry:
Bond Angle(s):
Polar or not?
Hybridization
Orbital Diagram of central atom alone
Orbital Diagram of central atom in compound
Chem201A
Dr. Baxley
c) PF6−
Lewis Structure, complete with formal charges
(show any possible resonance structures too!)
Molecular Geometry:
Bond Angle(s):
Polar or not?
Hybridization
Orbital Diagram of central atom alone (P–): add
one electron
Orbital Diagram of central atom in compound
d) TeCl2Br2
Lewis Structure, complete with formal charges
(show any possible resonance structures too!)
Molecular Geometry:
Bond Angle(s):
Polar or not?
Hybridization
Orbital Diagram of central atom alone
Orbital Diagram of central atom in compound
Chem201A
e) NO2−
Lewis Structure, complete with formal charges
(show any possible resonance structures too!)
Dr. Baxley
Molecular Geometry:
Bond Angle(s):
Polar or not?
Hybridization
Orbital Diagram of central atom alone
Orbital Diagram of central atom in compound
2. a. Draw the Lewis structure of acetone, (CH3)2CO (C in the middle, with two C’s and an O
bonded to it). What is the hybridization on each carbon atom in the molecule?
b. On the Lewis structure, identify the type of each bond (σ or π).
c. Describe the orbital location, including type of bond, of each pair of electrons in the
molecule including lone pairs (for example, there are six pairs of electrons in six
different σ bonds formed between an s orbital on a hydrogen and an sp3 hybrid orbital in
a carbon).
Chem201A
Dr. Baxley
3. Draw the Lewis structure and determine the hybridization on the central atom in each of the
following molecules. Then draw the orbital diagrams of the central atom alone, and the
central atom in the molecule.
a. BrF3
b. XeF4
c. HCN
4. Epinephrine, also called adrenaline, is a hormone and a neurotransmitter that, among other
things, is involved in the “fight or flight” response. The structure of epinephrine, with some
atoms labeled with numbers, is shown below. This representation does not show any lone
pairs of electrons, but all oxygen atoms with two bonds should have two lone pairs and
nitrogen atoms with three bonds should have one lone pair. This structure also does not
show all bonds. For the oxygen atom labeled 1, it has one bond to carbon #2 and one bond to
hydrogen. The carbon labeled number 5 has one bond to nitrogen #4 and three bonds to three
hydrogen atoms.
a. For each of the labeled atoms, identify the shape around that atom, the bond angle,
and the hybridization on that atom.
b. How many π bonds are in this structure?
Chem201A
Dr. Baxley
Answer Key
1.
a. molecular geometry: tetrahedral
bond angle: 109.5º
polar
sp3 hybridized
C alone
Cl
H C Cl
H
C in CCl2H2
2p
sp3
2s
b. molecular geometry: bent
bond angle: <120º
polar
sp2 hybridized
N alone
Cl N O
N in ClNO
2p
2p
sp2
2s
c.
molecular geometry: octahedral
bond angle: 90º
nonpolar
sp3d2 hybridized
Chem201A
Dr. Baxley
P– alone
P– in PF6–
3d
3d
3p
sp3d2
3s
d. molecular geometry: seew saw
(Br atoms are larger, so they will be in equatorial positions)
bond angle: <90º and <120º
polar
sp3d hybridized
e.
Te alone
Te in TeCl2Br2
5d
5d
5p
sp3d
5s
f. electron pair geometry: trigonal planar
molecular geometry: bent
bond angle: <120º
polar
sp2 hybridized
O N O
N alone
O N O
N in NO2–
2p
2p
2s
sp2
Chem201A
2.
Dr. Baxley
sp3
sp3
H
H
O
H
C
C
C
H
H
H
sp2
There are six pairs of electrons in six different σ bonds formed between an s orbital on a
hydrogen and an sp3 hybrid orbital in a carbon.
There are two pairs of electrons in two bonds formed between an sp3 hybrid orbitals on the
outside carbons and an sp2 hybrid orbital on the central carbon.
There is one pair of electrons in a σ bond between an sp2 hybrid orbital on the central carbon
and an sp2 hybrid orbital on the oxygen.
There is one pair of electrons in a π bond between the 2p orbital on the central carbon and the
2p orbital of the oxygen.
There are two lone pairs of electrons in sp2 hybid orbitals of the oxygen.
3. a. Lewis structure is below. Br is sp3d hybridized. Orbital diagrams are below.
Br alone
4d
4p
Br in BrF3
4d
sp3d
4s
b. Lewis structure is below. Xe is sp3d2 hybridized. Orbital diagrams are below.
Chem201A
Dr. Baxley
Xe alone
Xe in XeF4
5d
5d
5p
sp3d
5s
c. Lewis structure is below. C is sp2 hybridized. Orbital diagrams are below.
C alone
C in HCN
2p
2p
sp
2s
4. O1: bent, <109.5º, sp3
C2: trigonal planar, 120º, sp2
C3: tetrahedral, 109.5º, sp3
N4: trigonal pyramidal, <109.5º, sp3
C5: tetrahedral, 109.5º, sp3