H
C
C
C
C
H
HH
H
C
H
H
H
C
H
H
H
H
1
The larger a molecule is, the more complex its VSEPR diagram.
Complex structures take time to draw!
2. Line diagrams also focus on important structural details.
An example; the difference in the hydrocarbon backbone of the
geometrical isomers E-3-methyl-2-pentene and
Z-3-methyl-2-pentene
Let’s convert the line drawing of E-3-methyl-2-pentene to a VSEPR:
•Carbon atoms are assumed to be located at the end of each bond, which may be a
line or “set” of lines.
•Stable carbon atoms are always assumed to have four bonding interactions.
•Notice a double bond represents two bonding interactions
What do you think a triple bond represents?
•These missing bonds to carbons
are assumed to be to H, so H’s
are added.
H+H
H
+
+
1. When examining chemical reactivity
eliminating structural details not relevant to the
chemistry or simplifying VSEPR diagrams to
line diagrams reduces complexity.
Z-3-methyl-2-pentene
E-3-methyl-2-pentene
•The 3D nature is
completed by changing
bonds to wedges and
hatches where needed.
Compare your completed diagrams
to the model geometries given in
VSEPR to see if they are correct
H
C
C
C
C
H
HH
H
C
H
H
H
C
H
H
H
H
