Chapter 3: Ionic and Covalent Compounds
1. Which is not an ionic compound?
A) KCl B) Ca(NO3)2 C) CBr4
Ans: C Difficulty: Easy
D) AlBr3
2. Which is not a covalent compound?
A) Br2
B) NO2
C) NH3
D) NaNO2
E) More than one of the compounds above is not a covalent compound.
Ans: D Difficulty: Easy
3. In bonding, main group elements _____ to attain the electronic configuration of the
noble gas closest to them in the periodic table.
A) Gain electrons
C) Share electrons
B) Lose electrons
D) Gain, lose, or share electrons
Ans: D Difficulty: Easy
4. _____ are negatively charged ions that have _____ electrons than protons.
A) Anions, more B) Cations, more C) Anions, less D) Cations, less
Ans: A Difficulty: Medium
5. Which statement concerning the ion Li+ is correct?
A) Li+ has two total electrons.
B) Li+ has an octet of electrons in its valence shell.
C) Li+ is formed when a lithium atom gains one electron.
D) Li+ is formed when a lithium atom gains one proton.
Ans: A Difficulty: Difficult
6. What is the electron configuration of an F– ion?
A) 1s22s22p4 B) 1s22s22p5 C) 1s22s22p6 D) 1s22s22p63s1
Ans: C Difficulty: Difficult
7. What is the ion symbol for an atom with twenty (20) protons and eighteen (18)
electrons?
A) Ca B) Ca2+ C) Ar D) Ar2+ E) Ar2–
Ans: B Difficulty: Medium
Page 23
Chapter 3: Ionic and Covalent Compounds
8. When forming ions, metals typically do which of the following?
A) Lose electrons to form negatively charged ions
B) Gain protons to form cations
C) Gain electrons to form anions
D) Lose electrons to form positively charged ions
Ans: D Difficulty: Easy
9. What is the ion symbol for an atom with sixteen (16) protons and eighteen (18)
electrons?
A) S2– B) S C) Ar D) Ar2+ E) Ar2–
Ans: A Difficulty: Medium
10. How many protons and electrons are present in Co2+?
A) 27 protons, 27 electrons
C) 27 protons, 25 electrons
B) 27 protons, 29 electrons
D) 29 protons, 27 electrons
Ans: C Difficulty: Medium
11. What is the symbol for the ion formed by magnesium?
A) Mg2– B) Mg3+ C) Mg2+ D) Mg4–
Ans: C Difficulty: Medium
12. What is the charge of the ions formed by group 7A elements?
A) +1 B) +7 C) –1 D) –7
Ans: C Difficulty: Easy
13. What is the ion symbol of the oxide ion?
A) O2– B) O22– C) O2 D) O2+
Ans: A Difficulty: Medium
14. Which element has a variable charge?
A) Na B) Fe C) Al D) C
Ans: B Difficulty: Medium
15. Which pair of elements will form an ionic compound?
A) Sulfur and oxygen
C) Iron and chlorine
B) Copper and iron
D) Bromine and oxygen
Ans: C Difficulty: Easy
16. What is the formula for the ionic compound formed when potassium and bromine
combine?
A) PBr B) KBr C) KBr2 D) K2Br
Ans: B Difficulty: Easy
Page 24
Chapter 3: Ionic and Covalent Compounds
17. What is the formula for the ionic compound lithium oxide?
A) LiO B) LiO2 C) Li2O D) Li2O2
Ans: C Difficulty: Medium
18. Which statement best explains the basis for the octet rule?
A) Atoms are most stable when they have eight bonds.
B) Atoms lose, gain, or share electrons to become a stable, noble gas.
C) Atoms are most stable with eight protons in their nucleus.
D) Atoms are most stable with eight electrons in their valence shell and the electron
configuration of a noble gas.
Ans: D Difficulty: Difficult
19. What is the formula for the ionic compound formed when magnesium and oxygen
combine?
A) MgO B) MgO2 C) Mg2O D) Mg2O2
Ans: A Difficulty: Medium
20. What is the formula for the ionic compound formed when aluminum and sulfur
combine?
A) AlS B) Al2S3 C) AlS3 D) Al2S
Ans: B Difficulty: Difficult
21. What is the proper name for CuCl?
A) Copper chloride
B) Copper (I) chloride
Ans: B Difficulty: Difficult
C)
D)
Copper (II) chloride
Copper monochloride
22. What is the proper name for MgF2?
A) Magnesium fluoride
B) Magnesium (I) fluoride
Ans: A Difficulty: Easy
C)
D)
Magnesium (II) fluoride
Magnesium difluoride
23. What is the name of the SO42– ion?
A) Sulfide ion B) Sulfate ion C) Sulfite ion
Ans: B Difficulty: Medium
D) Bisulfate ion
24. What is the chemical formula for the ionic compound calcium selenide?
A) Ca2Se2 B) CaSe C) CaSe2 D) Ca2Se
Ans: B Difficulty: Medium
25. What is the chemical formula of tin (IV) cyanide?
A) Sn4CN B) SnCN4 C) Sn(CN)4 D) SnC4N4
Ans: C Difficulty: Difficult
Page 25
Chapter 3: Ionic and Covalent Compounds
26. The formula for zinc acetate is _____.
A) ZnCH3CO2 B) Zn(CH3CO2)2 C) Zn(HCO3)2
Ans: B Difficulty: Difficult
27. Which chemical formula is not correct?
A) Na2HCO3 B) NaNO3 C) Na2HPO4
Ans: A Difficulty: Difficult
D) Zn(HCl)8
D) Na2SO3
28. Which chemical formula is correct?
A) Ag(CH3CO2)2 B) K2CN C) Mg(OH)2
Ans: C Difficulty: Difficult
D) MgHCO3
29. An atom has the electron-dot symbol shown below. If this atom is a main group
element, what charge will it form in its ionic state?
A) –1 B) +3 C) –5 D) –3
Ans: B Difficulty: Easy
30. Which atom fits the electron-dot symbol shown below?
A) Li B) B C) N D) Na
Ans: B Difficulty: Medium
31. If atoms with the electron-dot symbols shown below are combined, what is the formula
of the ionic compound that is formed?
A) XY B) X2Y C) XY2 D) X2Y2
Ans: B Difficulty: Difficult
E) X3Y2
32. If atoms with the electron-dot symbols shown below are combined, what is the formula
of the ionic compound that is formed?
A) XY B) X2Y C) XY2 D) X2Y2
Ans: A Difficulty: Difficult
E) X3Y2
33. What period 4 element forms an ion with a –1 charge?
A) Sulfur B) Bromine C) Iodine D) Rubidium
Ans: B Difficulty: Medium
Page 26
Chapter 3: Ionic and Covalent Compounds
34. What is the name of the compound (NH4)2SO4?
A) Ammonium sulfide
C)
B) Ammonia sulfate
D)
Ans: D Difficulty: Difficult
Ammonia sulfoxide
Ammonium sulfate
35. Which compound has the highest melting point?
A) KCl B) CH4 C) C6H12O6 D) H2O
Ans: A Difficulty: Medium
36. What is the charge on the chromium ion in the ionic compound CrCl3?
A) +6 B) +3 C) –3 D) –6
Ans: B Difficulty: Difficult
37. What is the formula for the ionic compound formed from the lead (II) ion and the
carbonate ion?
A) Pb(CO3)2 B) PbCO3 C) Pb2CO3 D) PbCO4
Ans: B Difficulty: Difficult
38. The correct name for AuI3 is
A) Silver iodide B) Gold iodide
Ans: C Difficulty: Medium
C) Gold (III) iodide D) Gold iodide (III)
39. What is the formula for chromous cyanide?
A) CrCN B) Cr(CN)2 C) Cr(CN)3 D) Cr2CN
Ans: B Difficulty: Difficult
40. The diphosphate ion is a biologically important polyatomic ion. If the ionic compound
calcium diphosphate has the formula Ca2P2O7, which correctly represents the ion
symbol of the diphosphate ion?
A) P2O72– B) PO4– C) 2 PO46– D) P2O74–
Ans: D Difficulty: Difficult
41. What is another name for an unshared pair of electrons in a covalent compound?
A) Lone pair of electrons
B) Nonbonded electron pair
C) Bonding pair of electrons
D) Lone pair of electrons or nonbonded electron pair
Ans: D Difficulty: Easy
Page 27
Chapter 3: Ionic and Covalent Compounds
42. Which of the statements concerning chemical bonds is false?
A) The sharing of electrons between two nonmetal atoms results in a covalent bond.
B) The attraction between oppositely charged ions results in an ionic bond.
C) The term nonpolar is used to describe a covalent bond in which electrons are not
shared equally.
D) A bond dipole is the separation of charge that results when atoms sharing
electrons have different electronegativities.
Ans: C Difficulty: Medium
43. How many covalent bonds are generally formed by atoms with five valence electrons?
A) 1 B) 2 C) 3 D) 4 E) 5
Ans: C Difficulty: Medium
44. How many lone pairs of electrons are present in the Lewis structure of ammonia, NH3?
A) 0 B) 1 C) 2 D) 3 E) 4
Ans: B Difficulty: Easy
45. How many nonbonded electron pairs are in the Lewis structure below?
A) 2 B) 4 C) 6 D) 8
Ans: B Difficulty: Easy
E) 16
46. What is the Lewis structure for chloroethylene (C2H3Cl)?
A)
B)
C)
D)
Ans: C
Difficulty: Difficult
47. How many valence electrons are in a molecule of formaldehyde (CH2O)?
A) 16 B) 12 C) 10 D) 8
Ans: B Difficulty: Medium
Page 28
Chapter 3: Ionic and Covalent Compounds
48. Predict the bond angles around the carbon atom in the structure of carbonic acid shown
below. Don't forget to draw in lone pairs where needed to give octets.
A) 180° B) 120° C) 109.5°
Ans: B Difficulty: Medium
D) 90°
49. What is the molecular shape around the phosphorus atom in PH3?
A) Linear
B) Bent
C) Trigonal planar
D) Tetrahedral
E) Trigonal pyramidal
Ans: E Difficulty: Difficult
50. What are the bond angles in a tetrahedral geometry?
A) 180° B) 120° C) 109.5° D) 90°
Ans: C Difficulty: Easy
51. Aspartic acid is an amino acid used to synthesize proteins. How many lone pairs of
electrons need to be added to complete the aspartic acid structure shown below?
A) 4 B) 6 C) 8 D) 9
Ans: D Difficulty: Medium
52. Which of the following molecule(s) is(are) polar?
A) CO2 B) CH4 C) CBr4 D) CHBr3
Ans: D Difficulty: Difficult
53. Rank the atoms Br, Cl, and K in order of increasing electronegativity.
A) K < Br < Cl B) Cl < Br < K C) Br < Cl < K D) K < Cl < Br
Ans: A Difficulty: Difficult
54. Rank the atoms Br, Cl, and F in order of increasing electronegativity.
A) F < Br < Cl B) Cl < Br < F C) Br < Cl < F D) F < Cl < Br
Ans: C Difficulty: Medium
Page 29
Chapter 3: Ionic and Covalent Compounds
55. Which atom has the lowest electronegativity?
A) Al B) S C) Se D) Rb
Ans: D Difficulty: Medium
56. Which bond is the most polar?
A) C–N B) C–O C) C–C D) C–Cl
Ans: E Difficulty: Difficult
E) C–F
57. Which bond is the least polar?
A) C–N B) C–O C) C–C D) C–Cl
Ans: C Difficulty: Easy
E) C–F
58. Aspartic acid is an amino acid used to synthesize proteins. How many polar bonds are
in the aspartic acid structure shown below?
A) 4 B) 6 C) 9 D) 12
Ans: C Difficulty: Difficult
59. What is the correct chemical formula of selenium dioxide?
A) SO2 B) SeO2 C) Se2O D) OS2
Ans: B Difficulty: Easy
60. Which bond has the polarity incorrectly labeled?
A) + H–Cl – B) + O–C – C) + Cl–F – D)
Ans: B Difficulty: Medium
61. Which is the correct Lewis structure for OBr–?
A)
D)
B)
E)
C)
Ans: B
Difficulty: Difficult
Page 30
– Cl–Br +
Chapter 3: Ionic and Covalent Compounds
62. Estimate the bond angles around the sulfur atom in the structure shown below.
A) 90° B) 109.5° C) 120°
Ans: B Difficulty: Medium
D) 180°
63. What is the molecular shape around the nitrogen atom in the structure shown below?
A) Linear
B) Bent
C) Trigonal planar
D) Tetrahedral
E) Trigonal pyramidal
Ans: B Difficulty: Difficult
64. What is the molecular shape around the oxygen atom in the structure shown below?
A) Linear
B) Bent
C) Trigonal planar
D) Tetrahedral
E) Trigonal pyramidal
Ans: B Difficulty: Difficult
65. Which element may have more than eight valence electrons around it when present in a
covalent compound?
A) C B) B C) N D) P E) O
Ans: D Difficulty: Medium
66. Which molecule or ion has only two resonance structures to describe its bonding?
A) CO32– B) NO3– C) HCO31– D) SO3
Ans: C Difficulty: Difficult
Page 31
Chapter 3: Ionic and Covalent Compounds
67. Which of the following is classified as a group in the valence shell electron pair
repulsion (VSEPR) theory?
A) An atom
B) A lone pair of electrons
C) A valence electron
D) Either an atom or a valence electron
E) Either an atom or a lone pair of electrons
Ans: E Difficulty: Medium
68. Which molecule's Lewis structure contains an atom that violates the octet rule?
A) H2O B) BeH2 C) PCl3 D) H2Se
Ans: B Difficulty: Difficult
69. Which compound has the greatest number of valence electrons?
A) H2S
B) CH4
C) NH3
D) H2O
E) All of the molecules above have the same number of valence electrons.
Ans: E Difficulty: Medium
70. Which atom(s) in the structure below has(have) a partial negative charge (–)?
A) Carbon
B) Fluorine
C) Hydrogen
D) Nitrogen
E) Nitrogen and fluorine
Ans: E Difficulty: Medium
71. How many lone pairs of electrons need to be added to the Lewis structure of carbonic
acid shown below?
A) 0 B) 3 C) 4 D) 6
Ans: D Difficulty: Medium
Page 32
Chapter 3: Ionic and Covalent Compounds
72. What is the total number of bonding electrons in the structure below?
A) 5 B) 10 C) 20 D) 30
Ans: C Difficulty: Medium
73. Which Lewis structure is incorrect?
A)
B)
C)
D)
Ans: B
Difficulty: Difficult
74. The Lewis structure shown below is not a valid Lewis structure. What statement best
describes the error in the structure?
A)
B)
C)
D)
Ans:
The nitrogen atoms violate the octet rule.
The chlorine atoms violate the octet rule.
The structure contains an incorrect number of valence electrons.
Chlorine atoms and nitrogen atoms do not typically form bonds with each other.
C Difficulty: Difficult
Page 33
Chapter 3: Ionic and Covalent Compounds
75. Which of the statements concerning compounds is incorrect?
A) Compounds are formed when atoms of two or more different elements are
chemically bonded.
B) Ionic compounds are composed of cations and anions.
C) Covalent compounds are composed of metals and nonmetals.
D) Covalent compounds are composed of individual molecules.
Ans: C Difficulty: Easy
76. Which statement concerning chemical bonds is false?
A) A covalent bond involves the sharing of electrons between two nonmetal atoms.
B) An ionic bond is the attraction between oppositely charged ions.
C) A nonpolar bond is a covalent bond in which electrons are not shared equally
between the atoms.
D) Electronegativity is a measure of the attraction an atom has for the electrons it
shares in a bond.
Ans: C Difficulty: Easy
77. Considering the electronegativity values indicated for each element, which covalent
bond has the least degree of polarity?
C
Cl
F
O
N
2.5
3.0
4.0
3.5
3.0
A) C–N B) N–O C) F–F D) H–Cl
Ans: C Difficulty: Medium
H
2.1
78. The covalent bond between chlorine and iodine is a polar one. Which of the following
properly represents the direction of polarity in this bond?
A) + Cl–I – B) – Cl–I + C) + Cl–I – D) – Cl–I +
Ans: B Difficulty: Medium
79. The Lewis structure of formaldehyde is shown below. Which statement concerning this
structure is incorrect?
A)
B)
Two electrons are being shared between the carbon atom and the oxygen atom.
The oxygen atom has four valence electrons that are not being shared with another
atom.
C) The oxygen and carbon atoms each have an octet of electrons in their valence
shells.
D) The hydrogen atoms have filled valence shells.
Ans: A Difficulty: Medium
Page 34
Chapter 3: Ionic and Covalent Compounds
80. Anions are formed when a neutral atom gains one or more electrons.
A) True B) False
Ans: A Difficulty: Easy
81. The (II) in the name of the ionic compound lead (II) acetate specifically indicates that
there are two lead ions present in the compound.
A) True B) False
Ans: B Difficulty: Medium
82. Neutral atoms always contain an equal number of protons, neutrons, and electrons.
A) True B) False
Ans: B Difficulty: Medium
83. Ionic compounds are composed of individual molecules, discrete groups of atoms that
share electrons.
A) True B) False
Ans: B Difficulty: Easy
84. Ionic compounds are composed of positively and negatively charged ions held together
by strong electrostatic forces.
A) True B) False
Ans: A Difficulty: Easy
85. Bonding is the joining of two atoms in a stable arrangement.
A) True B) False
Ans: A Difficulty: Easy
86. Ionic bonds result from the sharing of electrons between two atoms.
A) True B) False
Ans: B Difficulty: Medium
87. A cation is positively charged, and has more electrons than the neutral atom.
A) True B) False
Ans: B Difficulty: Medium
88. The ionic formula for zinc oxide is ZnO2.
A) True B) False
Ans: B Difficulty: Medium
89. Ionic compounds have very high melting points compared to covalent compounds.
A) True B) False
Ans: A Difficulty: Easy
Page 35
Chapter 3: Ionic and Covalent Compounds
90. All ionic compounds are soluble in water.
A) True B) False
Ans: B Difficulty: Easy
91. An ionic compound is a pure substance formed by chemically combining two or more
nonmetal atoms together.
A) True B) False
Ans: B Difficulty: Medium
92. A polyatomic ion is an ion that forms more than one charge.
A) True B) False
Ans: B Difficulty: Easy
93. The name of an anion usually ends in the -ide if it is derived from a single atom or -ate
(or -ite) if it is polyatomic.
A) True B) False
Ans: A Difficulty: Medium
94. The correct name for CaHPO4 is calcium phosphate.
A) True B) False
Ans: B Difficulty: Medium
95. The symbol for the nitrite ion is NO2–.
A) True B) False
Ans: A Difficulty: Medium
96. The noble gas that has the same electronic configuration as the iodide ion is krypton.
A) True B) False
Ans: B Difficulty: Medium
97. Elements in group 2A form ions with a +2 charge.
A) True B) False
Ans: A Difficulty: Easy
98. Ionic compounds are usually solids at room temperature.
A) True B) False
Ans: A Difficulty: Easy
99. The formula for copper (II) hydroxide is Cu(OH)2.
A) True B) False
Ans: A Difficulty: Medium
100. Sodium nitrate and sodium nitrite are two acceptable names for the same compound.
A) True B) False
Ans: B Difficulty: Medium
Page 36
Chapter 3: Ionic and Covalent Compounds
101. Sodium bicarbonate and sodium hydrogen carbonate are two acceptable names for the
same compound.
A) True B) False
Ans: A Difficulty: Medium
102. The sulfite ion contains more oxygen atoms than the sulfate ion.
A) True B) False
Ans: B Difficulty: Medium
103. The carbonate ion contains the same number of oxygen atoms as the sulfate ion.
A) True B) False
Ans: B Difficulty: Medium
104. The electron configuration for the sulfide ion is 1s22s22p63s23p64s2.
A) True B) False
Ans: B Difficulty: Difficult
105. If the main group element has an electron-dot symbol of
ion will be +2.
A) True B) False
Ans: A Difficulty: Medium
106.
If the main group element has an electron-dot symbol of
ion will be –2.
A) True B) False
Ans: A Difficulty: Medium
107. All polyatomic ions are anions.
A) True B) False
Ans: B Difficulty: Easy
108. All isotopes of an element form the same type of ion.
A) True B) False
Ans: A Difficulty: Medium
109. All p block elements form ions.
A) True B) False
Ans: B Difficulty: Difficult
110. The ion symbol for the ferric ion is Fe2+.
A) True B) False
Ans: B Difficulty: Medium
Page 37
, the charge of the resulting
, the charge of the resulting
Chapter 3: Ionic and Covalent Compounds
111. An iron (III) ion has 29 protons and 26 electrons.
A) True B) False
Ans: B Difficulty: Medium
112. An iodide ion has 53 protons and 54 electrons.
A) True B) False
Ans: A Difficulty: Medium
113. Strontium and barium form ions with the same charge.
A) True B) False
Ans: A Difficulty: Easy
114. Potassium sulfide has the chemical formula K2S.
A) True B) False
Ans: A Difficulty: Medium
115. In crystal of an ionic compound, the cations are surrounded by anions so that the
charges of the ions are balanced.
A) True B) False
Ans: A Difficulty: Easy
116. The formula for stannic fluoride is SnF4.
A) True B) False
Ans: A Difficulty: Medium
117. The chemical formulas of ionic compounds are written with the cation first, and then the
anion, with subscripts to show how many of each are needed to have zero net charge.
A) True B) False
Ans: A Difficulty: Easy
118. A main group element is especially stable when it possesses eight total electrons.
A) True B) False
Ans: B Difficulty: Medium
119. When magnesium forms an ion it gains two electrons.
A) True B) False
Ans: B Difficulty: Medium
120.
When forming an ion, an atom with the electron-dot symbol of
a –3 charge by the loss of three electrons.
A) True B) False
Ans: B Difficulty: Medium
Page 38
forms an anion with
Chapter 3: Ionic and Covalent Compounds
121. A molecule is a discrete group of atoms held together by covalent bonds.
A) True B) False
Ans: A Difficulty: Easy
122. A Lewis structure shows the connectivity between atoms in a molecule, as well as
where all the bonding and nonbonding valence electrons reside.
A) True B) False
Ans: A Difficulty: Medium
123. Bonding is the joining of two atoms in a stable arrangement.
A) True B) False
Ans: A Difficulty: Easy
124. Atoms with three valence electrons generally form five bonds.
A) True B) False
Ans: B Difficulty: Medium
125. Atoms with seven valence electrons typically form one covalent bond.
A) True B) False
Ans: A Difficulty: Medium
126. Every atom must have an octet of electrons in order for a Lewis structure to be
considered valid.
A) True B) False
Ans: B Difficulty: Medium
127. Phosphorus usually forms two covalent bonds in a molecule.
A) True B) False
Ans: B Difficulty: Medium
128. A double bond consists of four electrons shared between two atoms.
A) True B) False
Ans: A Difficulty: Easy
129. The Lewis structure for BH3 contains an atom that does not follow the octet rule.
A) True B) False
Ans: A Difficulty: Medium
130. The Lewis structure for PH3 contains an atom that does not follow the octet rule.
A) True B) False
Ans: B Difficulty: Medium
Page 39
Chapter 3: Ionic and Covalent Compounds
131. Resonance structures for a substance differ only in the location of multiple bonds and
the position of lone electron pairs.
A) True B) False
Ans: A Difficulty: Medium
132. There can be no more than two resonance structures for a molecule.
A) True B) False
Ans: B Difficulty: Medium
133. The correct name for SF6 is sulfur heptafluoride.
A) True B) False
Ans: B Difficulty: Easy
134. The formula for dinitrogen pentoxide is N5O2.
A) True B) False
Ans: B Difficulty: Easy
135. A bond formed between the elements hydrogen and bromine would be considered an
ionic bond.
A) True B) False
Ans: B Difficulty: Easy
136. Unequal sharing of electrons in a covalent bond results in a polar bond.
A) True B) False
Ans: A Difficulty: Easy
137. Nonpolar molecules may contain polar bonds.
A) True B) False
Ans: A Difficulty: Medium
138. Some covalent compounds are solids, some are liquids, and some are gases at room
temperature.
A) True B) False
Ans: A Difficulty: Easy
139. C–H bonds are considered to be nonpolar, because the electronegativity difference
between carbon and hydrogen is small.
A) True B) False
Ans: A Difficulty: Medium
140. The symbol – is given to the more electronegative atom in a polar bond.
A) True B) False
Ans: A Difficulty: Medium
Page 40
Chapter 3: Ionic and Covalent Compounds
141. The structures shown below are resonance structures of sulfur dioxide.
and
A) True B) False
Ans: A Difficulty: Medium
142. The structures shown below are resonance structures of sulfur dioxide.
and
A) True B) False
Ans: B Difficulty: Medium
143. In the valence shell electron pair repulsion (VSEPR) theory, a group is defined as an
atom or a lone pair of electrons.
A) True B) False
Ans: A Difficulty: Medium
144. A molecule that contains only one polar bond is a polar molecule.
A) True B) False
Ans: A Difficulty: Easy
145. Ethane (C2H6) is a polar molecule.
A) True B) False
Ans: B Difficulty: Medium
146. A resonance hybrid is a composite of all resonance structures that spreads out electron
pairs in multiple bonds and lone pairs.
A) True B) False
Ans: A Difficulty: Medium
147. A bond between a carbon atom and a nitrogen atom is a polar covalent bond.
A) True B) False
Ans: A Difficulty: Medium
148. The molecule below is a polar molecule.
A) True B) False
Ans: A Difficulty: Medium
Page 41
Chapter 3: Ionic and Covalent Compounds
149. Double bonds and triple bonds are never polar bonds.
A) True B) False
Ans: B Difficulty: Difficult
150. A N–O bond is more polar than a P–O bond.
A) True B) False
Ans: B Difficulty: Medium
151. The molecule below is a polar molecule.
A) True B) False
Ans: A Difficulty: Medium
152. The shape around each carbon atom in the molecule below is trigonal planar.
A) True B) False
Ans: B Difficulty: Medium
153. The Lewis structure for the molecule below is incomplete because it is missing six pairs
of nonbonding electrons.
A) True B) False
Ans: A Difficulty: Medium
154. The shapes around the left and right carbon atoms in the structure below are tetrahedral
and linear, respectively.
A) True B) False
Ans: B Difficulty: Medium
155. A double bond is counted as two groups in the valence shell electron pair repulsion
(VSEPR) theory.
A) True B) False
Ans: B Difficulty: Medium
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Chapter 3: Ionic and Covalent Compounds
156. Dibromomethane (CH2Br2) is a nonpolar molecule.
A) True B) False
Ans: B Difficulty: Difficult
157. When writing Lewis structures, the symbol below is placed between resonance
structures.
A) True B) False
Ans: B Difficulty: Easy
158. The molecular shape around the boron atom in BCl3 is different than the molecular
shape around the nitrogen atom in NCl3.
A) True B) False
Ans: A Difficulty: Difficult
159. In Lewis structures, fluorine atoms generally do not obey the octet rule.
A) True B) False
Ans: B Difficulty: Easy
160. The electrons in the outermost occupied shell of an atom are called the _____ electrons.
Ans: valence
Difficulty: Easy
161. The _____ rule states that a main group element is especially stable when it possesses
eight electrons in its outer shell.
Ans: octet
Difficulty: Easy
162. The chemical formula for iron (III) bicarbonate is _____.
Ans: Fe(HCO3)3
Difficulty: Difficult
163. The formula for the ammonium ion is _____.
Ans: NH4+
Difficulty: Medium
164. The electron configuration of the oxide ion is _____.
Ans: 1s22s22p6
Difficulty: Difficult
165. The Ca2+ ion contains _____ protons.
Ans: 20 or twenty
Difficulty: Medium
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Chapter 3: Ionic and Covalent Compounds
166. In bonding, main group elements gain, lose, or share electrons to attain the _____ of the
nearest noble gas neighbor to them in the periodic table.
Ans: electron configuration
Difficulty: Medium
167. In general, a _____ bond will be one in which the electronegativity difference between
two atoms is 0.5 units or greater.
Ans: polar
Difficulty: Medium
168. Electronegativity _____ down a column of the periodic table as the atomic radius
increases.
Ans: decreases
Difficulty: Easy
169. In the Lewis structure of a molecule, oxygen atoms typically have _____ lone pair(s) of
electrons.
Ans: two or 2
Difficulty: Easy
170. Aspartic acid is an amino acid used to synthesize proteins. There are _____ atoms with
a trigonal planar geometry in the aspartic acid structure shown here.
Ans: two or 2
Difficulty: Difficult
171. The chemical formula for phosphorus pentachloride is _____.
Ans: PCl5
Difficulty: Easy
172. Carbon tetrachloride has _____ valence electrons.
Ans: thirty-two or 32
Difficulty: Medium
173. To represent the three-dimensional geometry of a tetrahedron on a two-dimensional
piece of paper, a solid line is used for the two bonds in the plane of the paper; a _____ is
used to show a bond that extends in front of the plane; and a _____ is used to show a
bond that extends behind the plane.
Ans: wedge, dashed line
Difficulty: Easy
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