Lewis Structure
1.
PF3
2.
OI2
3.
BF3 (boron is an exception: only needs
6 valence e-)
4.
SiI4
5.
CS2
# boding # lone Total ee- conc. e- pairs conc.
Picture of Shape
Shape Name
-
+
What did you observe between the
proton and the electron?
e
move towards the protons:
they are attracted to
each other
What holds electrons in an atom?
The attraction
+
between the e & p
-
-
What did you observe between the electrons?
Do electrons like each other
electrons?
NO
Conclusion….
e
like
+
p &…
e- REPEL
e- move as far away from each other…..
However, they do exist in pairs
(remember two per e- cloud shape)
Draw the following table
# OF
TOTAL
PAIRS
#
#
Shared Unshared
e- Pairs
e- Pairs
Shape
Picture
Examples
CO2, Cl2,
SiO2
BF3, CH2O
NH3, PCl3
CH4, CBr4
SCl2, H2O
Molecule Phet
V
S
E
P
R
# OF
TOTAL
PAIRS
2
# Share
e- Pairs
2
3 3
# Unshared
e- Pairs
Shape
Examples
CO2
Cl2
0
linear
0
Trigonal
Planar
BCl3
CH2O
Pyramidal
NH3
PCl3
4 3 1
4 4 0 Tetrahedral
THEORY
4
Picture
2 2
Bent
CH4
CBr4
SCl2
H2O
Pyramidal
Bent
Lewis Structure
1.
PF3
2.
OI2
3.
BF3 (boron is an exception: only needs
6 valence e-)
4.
SiI4
5.
CS2
# boding # lone Total ee- conc. e- pairs conc.
Picture of Shape
Shape Name
Molecule Phet
1. Which is a molecule?
A. CO2
B. CaCl2
C. NH4Cl
D. Li2SO4
2. Which has only single bonds?
A.
B.
C.
D.
E.
F.
PF3
OI2
BF3
SiI4
CS2
all single bonds
4. What shape is water?
A.
B.
C.
D.
Tetrahedral
Bent
Trigonal planar
Linear
5. Which is an example of an
exception to the octet rule?
A. O2
B. N2
C. BF3
D. I2
E. More than one of these
5ans. Which is an example of an
exception to the octet rule?
A. O2
B. N2
C. BF3
D. I2
E. More than one of these
6. Which molecule could
be represented with this
diagram?
A. BH3
B. CH4
C. NH3
7. Which molecule could
be represented with this
diagram?
A.
B.
C.
D.
HCl
CH4
NH3
F2