Download Chapter 7.4 - Atomic Orbitals: Hybridization

Chapter 7.4 - Atomic Orbitals: Hybridization
Reading Sheet
1.
On pages 185-186 of Chapter 7.4, it is explained that according to Valence Bond Theory, for an
atom to form a covalent bond it must have _____.
a. a high electronegativity
b. a low electronegativity
c. a valence shell electron
d. an unpaired electron in an atomic orbital
2.
On the same pages (see previous question), it is explained that Valence Bond Theory must be
revised because it would otherwise predict that the Be atom would form _____ bonds, the B
atom would form ____ bonds and the C atom would form _____ bonds.
3.
The Be atom of BeF2 forms two bonds; it does this by hybridizing or mixing _____ atomic
orbitals …
a. two s orbitals
b. two p orbitals
c. one s orbital and one p orbital
d. two s orbitals and two p orbitals
Notes from Class Discussion:
Valence Bond Theory would predict …
… in order to form _____ which are available for bonding with the two F atoms.
a. one sp orbital
b. two sp orbitals
c. two pp orbitals
d. two p2 orbitals
4.
Hybrid orbital theory can also explain why (and how) the B atom of BH3 forms three bonds; it
does this by hybridizing or mixing _____ atomic orbitals …
a. three s orbitals
b. three p orbitals
c. one s orbital and two p orbitals
d. two s orbitals and four p orbitals
… in order to form _____ orbitals which are available for bonding with the three H atoms.
a. three s2p
b. three sp2
c. two p3
d. six sp2
5.
Hybrid orbital theory can also explain why (and how) the C atom of CH4 forms four bonds; it
does this by hybridizing or mixing _____ atomic orbitals …
a. one s orbital and three p orbitals
b. four p orbitals
c. two s orbitals and two p orbitals
d. two s orbitals and six p orbitals
… in order to form _____ orbitals which are available for bonding with the four H atoms.
a. four s2p2
b. four p4
c. four sp3
d. eight sp3
6.
The P atom of PCl5 forms _____ hybrid orbitals in order to bond with the terminal atoms.
a. sp4
b. s2p3
c. sp3d
d. sp3d2
7.
The S atom of SF6 forms _____ hybrid orbitals in order to bond with the terminal atoms.
a. sp4
b. s2p3
c. sp3d
d. sp3d2
8.
Study Table 7.4; compare it to Table 7.3 (page 179) and complete the following statements.
• A molecule with a species type of AX3 will have a central atom with _______ hybridization.
Modified Valence Bond Theory assumes
hybridization (mixing) of atomic orbitals.
Mix one s and one p 
Mix one s and two p 
Mix one s and three p 
Mix one s, three p and one d 
Mix one s, three p and two d 
An atom hybridizes in such a manner that
all the electron groups have hybrid orbitals
as homes
Hybridization type and the AXiEj notation
go hand in hand:
AX2: hybridizes as
AX3: hybridizes as
• A molecule with a species type of AX3E will have a central atom with _______ hybridization.
AX4: hybridizes as
• A molecule with a species type of AX2E2 will have a central atom with ______ hybridization.
AX5: hybridizes as
• A molecule with a species type of AX3E2 will have a central atom with ______ hybridization.
AX6: hybridizes as
9.
Study Table 7.4; compare it to Table 7.3 (page 179) and complete the following statements.
• A molecule with linear geometry will have a central atom with _______ hybridization.
• A molecule with trig. planar geometry will have a central atom with _______ hybridization.
• A molecule with tetrahedral geometry will have a central atom with _______ hybridization.
10.
11.
12.
13.
14.
15.
16.
Now let's consider the Multiple Bonds sub-section of Chapter 7.4. Identify the following
statement as being either TRUE or FALSE: The six electrons in a triple bond are located in
three hybridized atomic orbitals. __________ If false, please explain your answer or correct
the statement.
Each carbon atom in the C2H4 molecule hybridizes to form _____ hybrid orbitals.
a. sp2
b. sp3
c. sp3d
d. sp3d2
Study Example 7.10. A molecule with 1 unshared electron pair, 1 single bond, and 1 double
bond will require _____ atomic orbitals and will hybridize as _____.
a. two, sp
b. three, sp2
c. four, sp2
d. four, sp3
There are two pairs of electrons (four electrons in all) shared in a double bond between two
atoms such as the C-C double bond of C2H4. What types of bonds are these two electron pairs
involved in?
a. two sigma bonds b. two pi bonds
c. one sigma and one pi bond
There are three pairs of electrons (six electrons in all) shared in a triple bond between two
atoms such as the C-C triple bond of C2H2. What types of bonds are these two electron pairs
involved in?
a. three sigma bonds
b. three pi bonds
c. two sigma and one pi bond
d. one sigma and two pi bonds
Now let's apply the information about sigma bonds and pi bonds to another molecule.
Describe the type of bonding in the C-N bond of the cyanide ion (CN - ). First draw the Lewis
structure. Then identify the bonding types.
a. two sigma bonds
b. two pi bonds
c. three sigma bonds
d. three pi bonds
c. one sigma and one pi bond
d. one sigma and one pi bond
g. two sigma and one pi bond
h. one sigma and two pi bonds
Draw the Lewis structure for the O2 molecule.
a. two sigma bonds
c. three sigma bonds
c. one sigma and one pi bond
g. two sigma and one pi bond
Then identify the bonding types.
b. two pi bonds
d. three pi bonds
d. one sigma and one pi bond
h. one sigma and two pi bonds
… continued …
AX2E1: hybridizes as
AX2E2: hybridizes as
AX3E1: hybridizes as
AX3E2: hybridizes as
AX5E1: hybridizes as
AX45E2: hybridizes as
Multiple Bonds
Double and triple bonds are unique:
• two electrons are in hybrid orbitals
• the remaining electrons are in nonhybridized p orbitals
• hybrid orbitals overlap along the axes
of the bond; this is called a sigma
bond overlap
• p orbitals overlap perpendicular to the
axis of the bond; these are called pi
bond overlaps
Consider CN-
Consider O2