7-2 Review and Reinforcement
Covalent Bonding
If the statement is true, write “true.” If it is false, change the underlined word or words to
make it true. Write your answer on the line provided.
____F, covalent_ 1. A group of atoms united by ionic bonds is called a molecule.
_______T______ 2. A covalent bond is formed by a shared pair of electrons
____F, four_____ 3. A double covalent bond consists of two shared electrons.
_______T______ 4. A molecular formula tells you how many atoms are in a single
molecule of the compound.
____F, MF_____ 5. The empirical formula for a molecule specifies which atoms are
bonded to each other in the molecule.
____F, lone pair_ 6. A pair of electrons not involved in bonding is called a shared
electron pair.
____F, equally__ 7. In nonpolar covalent bonds, the electrons are shared unequally
between two atoms.
____F, Triple___ 8. Lewis structures use a triple dash to represent a double bond.
Us the information in Figure 7-19 of the textbook to calculate the eletronegativity
differences between each pair of elements listed in the chart below. Then indicate
whether the bond would be nonpolar covalent, polar covalent, or ionic. Write your
answers in the chart.
Electronegativity Differences
9.
H-O
10.
C-H
11.
K-F
12.
N-H
13.
Na-F
14.
O-Cl
Type of Bond
7-2 Review and Reinforcement (continued)
Write Lewis structures for each of the following molecules. Indicated the bonds with
either dots of dashes.
15. NH3
H-N-H
H
16. H2
18. PCl3
Cl-P-Cl
Cl
19. CCl4
H-H
17. C2H4
H-C=C-H
H H
Cl
Cl- C- Cl
Cl
20. C2H6
H H
H-C-C-H
H H
Answer the following questions as directed.
21. Explain why the molecules SF4 is an exception to the octet rule.
Because the central atom(s) in SF4 has 10 electrons.
22. Explain the relationship between electronegativity and polarity.
The more the electronegativity differences, the more the polarity. For the
electronegativity differences of the molecule, 0.3< nonpolar covalent, 0.14-1.7 is polar
covalent, >1.7 is ionic.
23. Compare and contrast single, double, and triple covalent bonds.
In single bonds, molecules share 2 electrons. In double bonds, molecules share 4
electrons. In triple bonds, molecules share 6 electrons.