VSEPR THEORY
Valence Shell Electron Pair Repulsion Theory
Jf-- Assumptions
~
1. Molecules take the shape that produces the
strongest attractions and weakest repulsions. This
is the lowest potential energy.
2. Only count valence electrons.
3. Focus on the central atom.
4. Electron pairs move as far apart as possible.
5. Double bonds act the same as single bonds.
6. Unshared pairs produce greater repulsion than
shared pairs.
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.•••• JC.:
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Nrume
_ Date
CHAPTER
6
Class
_
REVIEW
Chemical Bonding
SHORT ANSWER
Answer the following questions in the space provided.
1. Identify the major assumption of the VSEPR theory that is used to predict the shape of atoms.
-f.--o~+ p4j&-1
"5c:~
2. In water, two hydrogen atoms are bonded to one oxygen atom. Why isn't water a linear molecule?
-}-4
c.ek+'--c.(
("{pc.. I
X
+ h..e.
U
.,..+0"""H'f
C!
+u
pc.;~s
hc.'s lone..
~J
What orbitals combine together to form
" A.
Sp3
+-
...be.."
+
d±
e,.-
wL..,'c-L
::!oks-at;.
I
hybrid orbitals around a carbon atom'l "
5. Arrange the following types of attractions in order of increasing strength, with 1 being the weakest
and 4 the strongest.
L/
covalent
3
ionic
2.
N M - IV "'"
W\ -
(3 u ~ ,{
;V M.
dipole-dipole
----1- L~ndon dispersion
13•••••.,(
~
polc.r
~ tJ.""
c;..Q"""'POIA.~.r
P e I c:"..
c." ~
rf'1.F
p 0 ~ r'\. ~s
.I At="
6. How are dipole-dipole attractions, London dispersion forces, and hydrogen bonding similar?
Mcdecwk..r
MODERN CHEMISTRY
HRW material copyrighted under notice appearing earlier in this work.
SECTION 6-5 REVIEW
49
Name
--:- __
Date
Class -.,....----
SECTION 6-5 continued
7. Complete:the following table:
Formula
Lewis structure
Geometry
Polar
y~5 - bl z, +kL Ccn+V-~ I
"'-AS CA..Y1.slte.:V'""~p( -e "
-J-r, ~
..
GO
\
p •.•,' r s
..
.cr
..
Al c:) -
I
:CI-t:.-C/:
,.
AJ c v..""-sJ,,.<~~ pa,'r-oS"
~« •.•..
+,.cl ••+o""""",.
ell'
I
.b Co H..,J.. J +0
C, e
"J. e.•••.-I,'
.'
:CI:
.
'
t"
c e ~ +r"C
C
I:
I
eo.+c.~
I.
~F
.. -13, F:.
'
A 5.3
··F:
.'
y
,
~ - '0;
e
S -
Sq ~
r-~,. s o '" -...r
H2.5.
H
Acr'Lcz..
: Cl:
PCls
I
:cr-¥
., / "
-C(:
.,
:F -
.,
ic I :
: C I:
., Aos
B~- p:
ABz..
SF6
F' F:
~
:~'
.'
:>
:r --- /' ..
7
'- /" l
: r-=
<,
L,'~r
St4...a.~
6; n= "-i,(t:(
"
F:
.~ .'\-: .' 4~
50
SECTION 6-5 REVIEW' .
",..
c:.+. ••...,
"
MODERN CHEMISTRY
HRW material copyrighted under notice appearing earlier in this work.
Name
Date
Modem Chemistry
•
Class
_
CHAPTER 6
HOMEWORK 6-9
(pp. 183-187)
VOCABULARY
Complete each sentence.
1. Molecular polarity is determined by /
+
'r-
eV1~
Q+
"/ fvL prt!!S(! I'\.
C\
C
e
-C'
t:J
c::;Vl.
~CJ{ec.,""k
2. According to VSEPR theory, the repulsion between the sets of valence-level electrons surrounding an
S"'-~fe.5
atom causes
~;+L-.
LCI(.J(..r.J--
Match the formula to the molecular shape predicted by VSEPR theory.
3. AB2
a. octahedral
c....
F
b. trigonal-pyramidal
5. AB3E
R
c. linear
6. ABs
Q
d. trigonal-bipyramidal
8. AB2~
~Jf.
-,
I
4. AB3
7. AB6~
("(,Pl..l..ritJr\.
e. bent
£;.
f. trigonal-planar
GRAPHIC ORGANIZER
On a separate sheet of paper, create a flow chart to show the steps in using VSEPR theory to
predict molecular geometry of a compound. Consider the use of Lewis structure in valence
electrons as you create your chart.
Use the steps in your chart as you use VSEPR theory to predict the molecular geometry of CI20.
STANDARDIZED TEST PREP
Circle the letter of the best answer.
1. A molecule with 2 atoms bonded to the central atom generally has which shape?
a. linear
b. bent
c. trigonal-planar
~itheraorb
2. Which is true of an AB4 molecule?
@The
b. The
c. The
d. The
electron pairs separate to form a tetrahedron.
molecule contains hydrogen.
molecule has ionic bonds.
molecule has both single and double bonds.
Modern Chemistry
Copyright © by Holt, Rinehart and Winston. All rights reserved.
~
s~
Name
Modem Chemistry
_
Date
Class
_
• CHAPTER 6
HOMEWORK 6-10
(pp.187-189)
VOCABULARY
\o/fine.
~hybriillzation-----------------------------------------------------------
~
hybrid orbitals
_
~swer
the questions.
What molecular geometry corresponds to sp hybridizati~?
l'---
_
X
_
Tetrahedral geometry is a result of what l>ybridization?
x.... A molecule with three hybrid orbitals
has what type of hybridization?
_
GRAPmC ORGANIZER
Complete the chart by writing the missing information. Use the following formulas as examples:
sci., BCI21 PH3, CCl4, NO~.
Molecular Shape
0
Linear
Bent
Formula Example
Lone Pairs of Electrons
(
J'Z-
~
0'"
~~,.~
Trigonal-planar
0
~-
Tetrahedral
0
.-
Trigonal-pyramidal
I
~
~
c»
STANDARDIZED TEST PREP
Circle the letter of the best answer.
1. VSEPR theory does not explain
a. the shapes of molecules.
b. how to use Lewis structures to predict the shapes of polyatomic ions.
@the relationship between a molecule's geometry and occupied orbitals.
d. that ~ouble and triple bonds are treated as single bonds in describing molecular geometry.
2. Which of the following affects molecular geometry?
a. the number of lone pairs of electrons on the atoms
b. the sizes of the different types of atoms
~ the hybridization of some of the orbitals of the atoms
~all
of the above
Modern Chemistry
Copyright © by Holt, Rinehart and Winston. All rights reserved.
.•..
~.