Name_____________________________________________period____________AP chemistry Unit 3 worksheet
Read chapter 8, 2.5-2.7
Practice problems:
1. Explain the difference between metallic, ionic, and covalent bonding.
2. Why can metals conduct electricity?
3. Predict the chemical formula of the ionic compound formed between the following pairs of elements
a. Al and F
b. K and S
c. Mg and N
d. Ba and O
4. Define the term lattice energy and tell what factors govern the magnitude of the lattice energy of an ionic
compound.
5. Arrange the following substances according to their expected lattice energies, listed them from lowest lattice
energy to highest: LiCl, KCl, KBr, CaO
6. a. The lattice energies of NaF and MgO are given in table 8.2 in the book. Account for the difference in these
two quantities.
b. Account for the difference in the lattice energies of MgCl2 and SrCl2, which are also listed in the table.
7. Explain the following trends in lattice energy
a. MgO > MgS
b. LiF > CsBr
c. CaO > KF
8. How is bonding in Cl2 different than NaCl?
9. Explain why a Br atom in Br2 satisfies the octet rule whereas a free Br atom does not.
10. Draw the Lewis structure for O2. The bond in O2 is shorter than the O-O single bond. Explain this observation.
11. Predict whether the following compounds are molecular or ionic
a. B2H6
b. CH3OH
c. LiNO3
d. Sc2O3
e. CsBr
f. NOCl
g. Ag2SO4
12. Which of the following bonds are polar?
a. P-O
b. S-F
c. Br-Br
13. Arrange the bonds in order of increasing polarity
a. C-F, O-F, Be-F
b. N-Br, P-Br, O-Br
14. Label each compound as ionic, polar covalent, or nonpolar covalent
a. CO
b. MgO
c. Cl2
d. AlF3
15. Draw the Lewis structure for the following
a. CO
b. N2
c. SF2
d. ClO2-
e. PCl3
e. H2CO (both H bonded to C)
16. a. Draw the Lewis electron-dot structures for CO32-, CO2 and CO, including resonance structures where
appropriate.
b. Which of the three species has the shortest C-O bond length? Explain the reason for your answer.
c. Account for the fact that the carbon-oxygen bond length in CO32– is greater than the carbon-oxygen bond
length in CO2.
17. How can the concept of resonance be used to explain that all six C-C bonds in benzene are equal in length.
18. Use simple structure and bonding models to account for each of the following:
(a) The bond length between the two carbon atoms is shorter in C2H4 than in C2H6.
(b) All the bond lengths in SO3 are identical and are shorter than a sulfur-oxygen single bond.
19. Draw the Lewis structure for each of the following molecules
a. CO32b. BH3
c. I3-
d. XeF4
20. Give the chemical formula for the following
a. Chlorite
b. chlorate
d.hypochlorite
c. perchlorate
e. AsF6-
21. In the Lewis structure for CH2Cl2, the number of unshared electron pairs
a. 2
b. 8
c. 10
d. 6
e. 4
22. In which of the following compounds does the bond between the central atom and chlorine have the greatest
ionic character?
a. BCl3
b. HCl
c. FeCl2
d. CCl4
e. CaCl2
Name or give the formula for each of the following
23. silver sulfide
47. MnO
24. sodium sulfite
48. P5O4
25. magnesium sulfate
49. Fe(OH)2
26. aluminum phosphate
50. Al(NO3)3
27. iron (III) sulfide
51. NiCr2O7
28. zinc phosphate
52. Cu2S
29. hydrosulfuric acid
53. HCl
30. barium acetate
54. CO
31. lead (II) bromide
55. NO3
32. copper (I) permanganate
56. H2SO3
33. carbonic acid
57. Cs2CO3
34. strontium cyanide
58. NH4ClO4
35. mercury (I) perchlorate
59. Sn(SO3)2
36. potassium oxalate
60. Pb(CN)2
37. dinitrogen trioxide
61. Ba(CH3COO)2
38. silver nitride
62. FePO4
39. hydrobromic acid
63. CaF2
40. calcium hydroxide
64. H3PO4
41. nitric acid
65. MgBr2
42. acetic acid
66. NaHCO3
43. dihydrogen monoxide
67. Ag2SO3
44. benzene
68. CH4
45. ammonia
69. H2O2
46. pentane
70. 2-Hexene
47. heptane
71. proponol
72. NO2
NO2NO2+
Nitrogen is the central atom in each of the species given above. Draw the Lewis electron-dot structure for each
of the three species.
73. Which one of the following molecules contains a triple bond?
a. PF3
b. NF3
c. C2H2
d. H2CO
e. HOF
74. Which of the following has the greatest dipole moment?
a. H2
b. HCl
c. HF
d. CO
75. Which of the following will conduct electricity? (there can be more than one answer)
a. solid Mg
b. solid NaCl
c. aqueous MgCl2
d. liquid Sn
e. solid CO2
f. liquid N2
76. Predict which of the following will have the highest boiling point
a. CO2
b. N2
c. NaCl
77. Which of the following ionic compounds has the smallest lattice energy?
a. Na2O
b. LiF
c. CaO
d. CaCl2
e. MgS
78. What are structural isomers? Draw two isomers of pentane.
Practice MCQ and FRQ
79. Which of the following explains why oxygen atoms, in their ground state, are paramagnetic?
a. Pauli exclusion principle
b. electron shielding
c. Hund’s rule d. aufbau principle
80. Calcium reacts with element X to form an ionic compound. If the ground-state electron configuration of X is
1s22s22p4, what is the simplest formula for this compound?
a. CaX
b. CaX2
c. Ca4X2
d. Ca2X2
Nonmetal
Ne
Si
P
S
Ar
No
SiF4
PF3
SF2
No
compound
compound
81. Some binary compounds that form between fluorine and various nonmetals are listed in the table above. A
student examines the data in the table and poses the following hypothesis: the number of F atoms that will
bond to a nonmetal is always equal to 8 minus the number of valence electrons in the nonmetal atom.
(a) Based on the student’s hypothesis, what should be the formula of the compound that forms between
chlorine and fluorine?
Formula of
compound
C
CF4
N
NF3
O
OF2
(b) In an attempt to verify the hypothesis, the student researches the fluoride compounds of the other halogens
and finds the formula ClF3 . Draw a complete Lewis electron-dot diagram for a molecule of ClF3 .
In an attempt to resolve the existence of the ClF3 molecule with the hypothesis stated above, the student researches the
compounds that form between halogens and fluorine, and assembles the following list
Halogen
Formula(s)
F
F2
Cl
Br
BrF, BrF3, BrF5
I
IF, IF3, IF5, IF7
(c). Based on concepts of atomic structure and periodicity, propose a modification to the student’s previous
hypothesis to account for the compounds that form between halogens and fluorine.
82. Bronze (Cu and Sn); Steel (Fe and C). Which of the following correctly describes the malleability of both alloys
compared to their primary metal?
a. Bronze’s malleability would be comparable to that of copper, but steel’s malleability would be
significantly lower than that of iron.
b. Bronze’s malleability would be significantly higher than that of copper, but steel’s malleability would be
comparable to that of iron.
c. Both bronze and steel would have malleability values similar to those of their primary metals
d. Both bronze and steel would have malleability values greater than those of their primary metal.
Review
83. a. What are valence electrons?
b. How many valence electrons does nitrogen have?
c. An atom has the electron configuration 1s22s22p63s23p2. How many valence electrons does this atom have?
84. If an atom has the electron configuration 1s22s22p5, how many electrons must it gain to achieve an octet?
85. Fill in the gaps
52 3+
130 Symbol
Cr
I
Protons
47
33
Neutrons
60
69
42
Electrons
46
48
Net charge
2+
386. What is the nuclear charge for the following atoms
a. Na
b. F
c. Sn
d. P
e. Ar
87. Why doesn’t a valence electron “feel” the full nuclear charge of an atom?
88. Which atom will have the largest radius in each pair.
a. K, Na
b. Na, Na+
c. Br, Brd. K, Br
89. Which property generally increases down a group but decreases from left to right
b. Melting point b. electronegativity
c. ionization energy
d. atomic radius
90. A. What is the name of group 1?
B. What is the name of group 17?
91. Which pair of elements has the most similar properties?
c. Na, S
b. N, P
c. P, Cl
92. Convert
d. 67.5 g of magnesium chloride to moles
d. N, Cl
e. 5.3 x 1023 molecules of nitrogen dioxide to grams
f.
0.761 moles of ammonia to milligrams
93. Write the electron configuration for each of the following ions
Sr2+
b. Ni2+
c. Br94. Which of the following are empirical formulas?
a. N2O
b. MgCl2
d. Mn3+
c. C2H6
95. Which is a list of elements listed in order of increasing ionization energy?
A) Na, K, Rb
B) Ne, Ar, Kr
C) Al, Mg, Na
D) Br, Cl, F
E) O, S, Se