Name:____________________________
Date:___________
Period:____
Review Chemistry I Honors Unit 7: Covalent Bonding and Nomenclature
1. Why do atoms share electrons in covalent bonds?
________________________________________________________________
2. A molecule is a neutral group of atoms held together by ______ .
A.
B.
C.
D.
ionic bonds
unshared electrons
partial charges
covalent bonds
3. Compounds formed by covalent bonds usually contain _______________.
A.
B.
C.
D.
halogens and oxygen
two or more nonmetals
a metal and a nonmetal
positive and negative ions
4. Which of the following is a molecular compound?
A.
B.
C.
D.
Na2O
AlCl3
SCl6
CuO
5. Carbon can form up to 4 bonds on each atom so it can form _________________.
A.
B.
C.
D.
8 valance electrons
large, long chain biomolecules
ionic bonds easily
metallic compounds
6. How do atoms form double covalent bonds?
A.
B.
C.
D.
C
C
One atom loses two electrons to the other atom in the bond.
Two atoms share two pairs of electrons.
Two atoms share two single electrons.
Two atoms share one electron.
7. Which of these elements does NOT exist as a diatomic molecule?
A.
B.
C.
D.
P
Cl
O
N
?
?
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8. A bond formed between a carbon atom and hydrogen atom is likely to be ____.
A.
B.
C.
D.
polar covalent
dipolar
ionic
nonpolar covalent
9. Which of the following bonds is the most polar (i.e. has the greatest difference in electronegativity)?
A.
B.
C.
D.
C—C
H—N
O—H
H—Cl
10. Which of the following covalent bonds is the least polar?
A.
B.
C.
D.
H—Cl
H—C
Cl—Cl
H—N
11. Which is TRUE of a nonpolar covalent bond?
A.
B.
C.
D.
electrons are shared unequally between atoms
a cation is bonded to an anion
electrons are transferred between atoms
electrons are shared equally in atoms
12. Draw the Lewis dot structure for CO2 in the box:
Does CO2 contain polar bonds? _____
If so, how many? ____
Is CO2 a polar molecule? _____
If not, explain why not. _____________________
_______________________________________
13. The following molecules contain polar bonds. Which is the only nonpolar molecule?
A.
B.
C.
D.
HCl
NH3
H2O
CBr4
2
14. Describe how London dispersion forces occur between two atoms or molecules.
___________________________________________________________________
___________________________________________________________________
15. Describe dipole-dipole interactions.
___________________________________________________________________
16. Describe how a hydrogen bond forms between two molecules.
__________________________________________________________________
__________________________________________________________________
17. List the intermolecular attractions in decreasing order from strongest to weakest:
_____________________ < _____________________ < _____________________
Weakest
Strongest
water molecule
water molecule
18. Water molecules are polar because they have _____________________________
that are arranged _____________________________.
19. There are strong attractions between polar water molecules which cause water to
have all of the following properties EXCEPT ____.
A.
B.
C.
D.
surface tension
liquid of greater density than solid (ice)
attraction to nonpolar molecules
higher boiling point
21. Hydrogen sulfide (H2S) boils at –60oC. Even though water is a smaller molecule that
should become a gas more easily than H2S, water doesn’t boil until it reaches 100oC.
Why are water molecules so difficult to separate from liquid phase to form a gas?
___________________________________________________________________
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22. Which substance has hydrogen bonding as its main intermolecular force?
A.
B.
C.
D.
SO2
HCl
F2
NH3
How do you recognize a molecule that can form hydrogen bonds?
___________________________________________________________________
23. Describe properties that are common in typical molecular compounds.
conductor:
good or poor
melting point: high
or
low
boiling point: high
or
low
net charge:
neutral or charged
#24-29 Write the NAME or FORMULA for the following molecular compounds:
24. CS2
______________________________
25. CCI4
______________________________
26. S2O6
______________________________
27. triboron monoxide
_______
28. tetraphosphorus pentoxide
_______
29. arsenic trihydride
_______
30. In drawing a Lewis structure, what is special about hydrogen (H) ?
A.
B.
C.
D.
It achieves an octet of 8 electrons.
It can form up to four bonds with 8 shared electrons.
It can only form one double bond.
It can only form one single bond with no unshared electrons around it.
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For #31-36 ,
Draw the Lewis dot structures for the following compounds.
List how many unshared pairs of electrons are in the molecule.
Label the molecule as polar or nonpolar.
Name the molecular geometry and list the bond angle.
31. HBr
unshared pairs: ___
polar or nonpolar
geometry: ____________________
bond angle: _____o
32. NI3
unshared pairs: ___
polar or nonpolar
geometry: ____________________
bond angle: _____o
33. BF3
unshared pairs: ___
polar or nonpolar
geometry: ____________________
bond angle: _____o
34. SO2
unshared pairs: ___
polar or nonpolar
geometry: ____________________
bond angle: _____o
35. CH2F4
unshared pairs: ___
polar or nonpolar
geometry: ____________________
bond angle: _____o
36. C2H4
unshared pairs: ___
polar or nonpolar
(around one of the C atoms)
geometry: ____________________
bond angle: _____o
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