Chapter 3: Structure and Properties of Ionic and Covalent
Compounds
1. In a Lewis structure, what do the dots represent?
Ans: valence electrons
2. Draw the Lewis structure of the fluoride ion.
Ans:
3. What are the two principal types of bonding called?
Ans: ionic bonding and covalent bonding
4. Name the two classes of elements which are most likely to form an ionic compound if
they are allowed to react with each other.
Ans: metal, nonmetal
5. Draw the Lewis structure of the Pb2+ ion.
Ans:
6. What constitutes a covalent bond between two atoms?
Ans: a shared pair of electrons
7. In what way is a polar covalent bond similar to a nonpolar covalent bond? In what way
are they different?
Ans: In each case, the bond consists of an electron pair shared between the bonded
atoms. The difference is that the sharing is unequal in the case of the polar
covalent bond, equal in a nonpolar covalent bond.
8. What does it mean if an atom is said to have a high electronegativity?
Ans: The atom has a strong attraction for shared electron pairs (electrons in covalent
bonds).
9. The elements with the lowest electronegativities are found in the _______ _______
region of the periodic table.
Ans: bottom left
10. Who first assigned electronegativity values to many of the elements?
Ans: Pauling
11. What do we call the three-dimensional arrangement of positive and negative ions in an
ionic solid?
Ans: crystal lattice
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Chapter 3 Structure and Properties of Ionic and Covalent Compounds
12. Predict the formula of the compound formed when ions of calcium and nitrogen
combine.
Ans: Ca3N2
13. What is the name of Fe2+ in the Stock system?
Ans: iron(II) ion
14. What does the suffix “-ic” on the common names of ions mean?
Ans: higher positive charge
15. What is the term used for ions that are composed of two or more atoms bonded
together?
Ans: polyatomic
16. What is the name of the ion NH4+?
Ans: ammonium
17. Provide the name of Na3PO4.
Ans: sodium phosphate
18. What kind of compound results when two or more different nonmetals share electrons?
Ans: covalent
19. What kind of bonding exists in substances which consist of discrete molecules?
Ans: covalent
20. Provide the formula of sulfur trioxide.
Ans: SO3
21. Write the formula of ammonia.
Ans: NH3
22. Provide the name of the compound whose formula is N2O5.
Ans: dinitrogen pentoxide
23. At what temperature is a liquid converted into a gas?
Ans: boiling point
24. What is the term that describes a solid with no regular structure?
Ans: amorphous
25. What is the term that describes a compound that, when dissolved in water, conducts an
electric current?
Ans: electrolyte
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Chapter 3 Structure and Properties of Ionic and Covalent Compounds
26. What kind of bonding is present in substances that are nonelectrolytes?
Ans: covalent
27. Draw the Lewis structure of methanethiol, CH3SH.
Ans:
28. Draw the Lewis structure of hydrogen sulfide, H2S.
Ans:
29. What is wrong with the Lewis structure shown for sulfur trioxide, SO3?
Ans: The structure shows 26 valence electrons, but there should only be 24.
30. Ozone, O3, has two resonance forms. Draw them, given the skeletal arrangement
OOO.
Ans:
31. What is defined as the amount of energy needed to break a bond holding two atoms
together?
Ans: bond energy
32. What is defined as the distance of separation of two nuclei in a covalent bond?
Ans: bond length
33. What do the letters VSEPR stand for?
Ans: Valence Shell Electron Pair Repulsion
34. The ammonia molecule, NH3, is polar. Why does this fact suggest that its shape is
trigonal pyramidal, rather than trigonal planar?
Ans: If the molecule were trigonal planar, the symmetry would result in a nonpolar
molecule. The centers of positive and negative charge would coincide.
35. How many dots are shown in the Lewis structure for the fluorine atom?
A) 5
B) 6
C) 7
D) 8
E) 10
Ans: C
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Chapter 3 Structure and Properties of Ionic and Covalent Compounds
36. Predict the formula of the compound formed when ions of sodium and sulfur combine.
A) Na2S
B) NaS2
C) NaS
D) Na2S2
E) Na3S
Ans: A
37. What is the formula of the sulfate ion?
A) SO4–
B) SO3–
C) SO42–
Ans: C
D) SO32–
38. What is the name of the ion NO2–?
A) nitrogen dioxide ion
B) nitrate ion
C) nitrote ion
Ans: D
D)
E)
39. What is the name of CuF2 in the Stock system?
A) copper(I) fluoride
D)
B) copper(II) fluorate
E)
C) copper difluoride
Ans: E
40. Write the formula of sodium carbonate.
A) NaCO2
B) Na2CO2
C) Na2CO3
Ans: C
41. Provide the name of CCl4.
A) carbon tetrachloride
B) carbon(IV) chloride
C) carbon chloride
Ans: A
D)
E)
E) SO22–
nitrite ion
nitride ion
copper fluoride
copper(II) fluoride
D) Na(CO3)2
E) Na3CO3
carbochloride
carbonate chloride
42. How many bonding electrons are shown in the Lewis structure for the bicarbonate ion,
HCO3–?
A) 6
B) 8
C) 10
D) 12
E) 14
Ans: C
43. If the shape of a molecule is tetrahedral, what are the values of the bond angles?
A) 90o
B) 109.5o
C) 120o
D) 180o
E) 90o and 120o
Ans: B
44. In the molecule AX2, the central atom A has two lone pairs of electrons in addition to
the two bond pairs in the AX bonds. What is the shape of this molecule?
A) bent, bond angle close to 109.5o
D) trigonal planer
B) bent, bond angle close to 120o
E) trigonal pyramid
C) linear
Ans: A
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Chapter 3 Structure and Properties of Ionic and Covalent Compounds
45. Which of the following Lewis structures of ions is incorrect?
A) [Na]+
Ans: E
B) [Ca]2+
C) [Sn]4+
D)
E)
46. Which of the following Lewis structures of ions is incorrect?
A) [Na]+
Ans: C
B) [Ca]2+
C) [Sn]2+
D)
E)
47. Which of the following has the greatest electronegativity?
A) H
B) Cl
C) O
D) F
E) Na
Ans: D
48. Which of the following has the greatest electronegativity?
A) Si
B) P
C) Cl
D) Ar
E) Br
Ans: C
49. In the compound CH3Cl, the bond between carbon and chlorine is _____________.
A) intermolecular
B) ionic
C) nonpolar covalent
D) polar covalent
Ans: D
50. Which one of the following is NOT true about elements that form cations?
A) The atoms lose electrons in forming ions.
B) The elements are metals.
C) They are located to the left of the periodic table.
D) They have low ionization energies.
E) They have high electron affinities.
Ans: E
51. Assuming reactions between the following pairs of elements, which pair is most likely
to form an ionic compound?
A) copper and tin
D) carbon and chlorine
B) chlorine and oxygen
E) fluorine and iodine
C) cesium and iodine
Ans: C
52. What kind of bond results when electron transfer occurs between atoms of two different
elements?
A) ionic
B) covalent
C) nonpolar
D) single
E) double
Ans: A
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Chapter 3 Structure and Properties of Ionic and Covalent Compounds
53. What is the Stock name of Cu+?
A) cupric ion
B) cuprous ion
C) copper(I) ion
Ans: C
D)
E)
54. Give the name of Fe2(SO4)3 in the Stock system.
A) iron monosulfuric acid
D)
B) iron(II) sulfate
E)
C) iron(III) sulfate
Ans: C
copper(II) ion
ferrous ion
ferrous sulfate
ferric sulfate
55. Assuming reactions between the following pairs of elements, which pair is most likely
to form a covalent compound?
A) lithium and iodine
D) copper and tin
B) sodium and oxygen
E) carbon and oxygen
C) calcium and chlorine
Ans: E
56. A double bond between two atoms, A and B, _______________.
A) is longer than a single bond between the same two atoms
B) has a lower bond energy than a single bond between the same two atoms
C) arises when two electrons are transferred from A to B
D) consists of two electrons shared between A and B
E) consists of four electrons shared between A and B
Ans: E
57. What is the correct formula of diphosphorous pentaoxide?
A) PO
B) PO3
C) P2O4
D) P2O5
E) P5O
Ans: D
58. What term describes the temperature at which a solid is converted into a liquid?
A) critical point
D) melting point
B) flash point
E) boiling point
C) sublimation point
Ans: D
59. What term describes a solution of a compound in water that does not conduct an electric
current?
A) amorphous solution
D) superconducting solution
B) an electrolyte solution
E) isoelectric solution
C) a nonelectrolyte solution
Ans: C
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Chapter 3 Structure and Properties of Ionic and Covalent Compounds
60. How many bonding electrons are in CO2?
A) 1
B) 2
C) 3
D) 4
E) 8
Ans: E
61. How many nonbonding electrons are in CH4?
A) 0
B) 1
C) 2
D) 3
E) 8
Ans: A
62. How many valence electrons are in SO42-?
A) 2
B) 64
C) 32
D) 12
E) 16
Ans: C
63. According to the VSEPR theory, if the central atom has three bonded atoms and one
lone pair, the geometry (shape) at this atom will be ______________________.
A) linear
D) trigonal pyramidal
B) bent (angular)
E) tetrahedral
C) trigonal planar
Ans: D
64. Which of the following are essential features in ionic bonding?
A) Elements with high ionization energy form bonds with elements with high
electron affinity.
B) Elements with high ionization energy form bonds with elements with low electron
affinity.
C) Elements with low ionization energy form bonds with elements with low electron
affinity.
D) Elements with low ionization energy form bonds with elements with high electron
affinity.
E) The ionization and electron affinity of elements does not determine bonding.
Ans: D
65. Which of the following bonds would be the most polar?
A) P–F
B) N–F
C) S–Cl
D) Br–Br
E) F–F
Ans: A
66. A covalent bond is
A) formed when two metals share a pair of electrons.
B) formed when a metal and a nonmetal share a pair of electrons.
C) formed when a nonmetal donates an electron to a metal.
D) formed between cations and anions.
E) formed when two nonmetals share a pair of electrons.
Ans: E
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Chapter 3 Structure and Properties of Ionic and Covalent Compounds
67. The formula of iron(III) bromide is
A) FeBr.
B) Fe3Br.
C) Fe3Br3.
Ans: D
68. Give the correct name for N2O5.
A) nitrogen(IV) oxide
B) dinitrogen pentoxide
C) nitrogen oxide
Ans: B
69. Give the correct name for Mg(CN)2.
A) manganese carbon nitride
B) manganese dicyanide
C) magnesium dicarbon dinitride
Ans: E
D) FeBr3.
E) Fe2Br3.
D)
E)
nitrate
nitrite
D)
E)
magnesium(II) dicyanide
magnesium cyanide
70. A certain compound has a very high melting point and when it dissolves in water the
solution conducts electricity. Which one of the following compounds would have these
properties?
A) O2
B) Cr
C) CCl4
D) Na2SO4
E) He
Ans: D
71. Which of the following would not describe the Lewis structure of PF3?
A) The Lewis structure has a double bond between phosphorus and one of the
fluorine atoms.
B) No resonance structures can be drawn.
C) The molecule has a lone pair (nonbonding pair) on the central atom.
D) The Lewis structure has 26 valence electrons.
E) The Lewis structure is not an exception to the octet rule.
Ans: A
72. Draw the Lewis structure of F2, O2 and N2. Which statement is true?
A) All three molecules have single bond between the atoms.
B) Both O2 and N2 have double bonds connecting the atoms.
C) Fluorine has the shortest bond between the two atoms.
D) The bond between the nitrogen atoms in N2 is stronger than the bond in F2 and O2.
E) All three molecules have triple bonds between the atoms.
Ans: D
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Chapter 3 Structure and Properties of Ionic and Covalent Compounds
73. Which of the following Lewis structures would not have a resonance structure?
A) A
Ans: B
B) B
C) C
D) D
E) E
74. Which of the following compounds have the expanded octet exception to the octet rule?
A) BeH2
B) NO
C) PF5
D) CH4
E) BF3
Ans: C
75. What is the molecular geometry of CO2?
A) linear
B) trigonal Planar
C) angular
tetrahedral
Ans: A
76. Which of following molecules is polar?
A) CF4
B) BeH2
C) SO2
D) F2
Ans: C
D) trigonal Pyramidal
E)
E) CO2
77. Which statement is true concerning the solubility of a substance in H2O?
A) Polar and nonpolar substances are equally soluble in water.
B) A nonpolar substance is soluble in water.
C) All substances are soluble in water.
D) Solubility of a substance in water has no relationship to the polarity of the
substance being dissolved.
E) A polar substance is soluble in water.
Ans: E
78. In Lewis structures, the chemical symbol of an element represents both the nucleus and
the lower energy (nonvalence) electrons.
Ans: True
79. The name of SnO2 is tin(II) oxide.
Ans: False
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Chapter 3 Structure and Properties of Ionic and Covalent Compounds
80. The common name of iron(III) chloride is ferric chloride.
Ans: True
81. There are three atoms of iodine represented in the formula NaIO3.
Ans: False
82. In solid NaCl, no molecules of NaCl exist.
Ans: True
83. Ionic solids are amorphous.
Ans: False
84. Molecular compounds usually involve ionic bonding.
Ans: False
85. As a rule, ionic compounds tend to have lower melting and boiling points than covalent
compounds consisting of small molecules.
Ans: False
86. In the molecule BeF2, the beryllium atom is an exception to the octet rule.
Ans: True
87. The NO molecule can never satisfy the octet rule.
Ans: True
88. Six electrons shared between two atoms corresponds to a triple bond.
Ans: True
89. Resonance occurs when two or more different, valid Lewis structures can be drawn for a
molecule.
Ans: True
90. The existence of resonance makes a molecule less stable than would otherwise be the
case.
Ans: False
91. Because the C-H bond in methane is polar, the CH4 molecule will also be polar.
Ans: False
92. Hydrogen bonds are intermolecular forces.
Ans: True
93. In determining properties such as solubility, melting point, and boiling point,
intramolecular forces are more important than intermolecular forces.
Ans: False
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Chapter 3 Structure and Properties of Ionic and Covalent Compounds
94. As a rule, a polar substance will be a good solvent for nonpolar solutes, and vice versa.
Ans: False
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