1. No category

Sample Test Chapter 4. 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 bromine atom.
Ans.
3. How many dots are shown in the Lewis structure for the sulfur atom?
Ans. six
4. What are the two principal types of bonding called?
Ans. ionic bonding and covalent bonding
5. Name the two classes of element which are most likely to form an ionic
compound if they are allowed to react with each other.
Ans. metal, nonmetal
6. Draw the Lewis structure of the Pb2+ ion.
Ans.
7. What constitutes a covalent bond between two atoms?
Ans. a shared pair of electrons
8. 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.
9. 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).
10. The elements with the lowest electronegativities are found in the
_______ _______ region of the periodic table.
Ans. bottom left
11. Who first assigned electronegativity values to many of the elements?
Ans. Pauling
12. What do we call the three-dimensional arrangement of positive and
negative ions in an ionic solid?
Ans. crystal lattice
13. Predict the formula of the compound formed when ions of sodium and
sulfur combine.
Ans Na2S
14. Predict the formula of the compound formed when ions of barium and
nitrogen combine.
Ans. Ba3N2
15. What is the name of Fe2+ in the Stock system?
Ans. iron(II) ion
16. What does the suffix "-ous" on the common names of ions mean?
Ans. lower positive charge
17. What is the term used for ions that are composed of two or more atoms
bonded together?
Ans. polyatomic
18. What is the formula of the sulfate ion?
Ans. SO4219. What is the name of the ion HCO3-?
Ans. hydrogen carbonate or bicarbonate
20. What is the name of the ion NH4+?
Ans. ammonium
21. Provide the name of Na3PO4.
Ans. sodium phosphate
22. What is the name of Cu2O in the Stock system?
Ans. copper(I) oxide
23. Write the formula of sodium carbonate.
Ans. Na2CO3
24. What kind of compound results when two or more different nonmetals
share electrons?
Ans. covalent
25. What kind of bonding exists in substances which consist of discrete
molecules?
Ans. Covalent
26. Provide the formula of sulfur trioxide.
Ans. SO3
27. Write the formula of ammonia.
Ans NH3
28. Provide the name of CCl4.
Ans. carbon tetrachloride
29. Provide the name of the compound whose formula is N2O5.
Ans. dinitrogen pentoxide
30. At what temperature is a liquid converted into a gas?
Ans. boiling point
31. What is the term that describes a solid with no regular structure?
Ans. amorphous
32. What is the term that describes a compound that, when dissolved in
water conducts an electric current?
Ans. electrolyte
33. What is the term that describes a compound that, when dissolved in
water does not conduct an electric current?
Ans. nonelectrolyte
34. What kind of bonding is present in substances which are
nonelectrolytes?
Ans. covalent
35. How many bonding electrons are shown in the Lewis structure for the
bicarbonate ion, HCO3-?
Ans. ten
36. Draw the Lewis structure of methylamine, CH3NH2.
37. Draw the Lewis structure of hydrogen sulfide, H2S.
38. What is wrong with the Lewis structure shown below for sulfur trioxide, SO3?
The structure shows 26 valence electrons, but there should only be 24.
39. Ozone, O3, has two resonance forms. Draw them, given the skeletal
arrangement O-O-O
40. What is defined as the amount of energy needed to break a bond holding
two atoms together?
Ans. energy
41. What is defined as the distance of separation of two nuclei in a
covalent bond?
Ans. bond length
42. What do the letters VSEPR stand for?
Ans. Valence Shell Electron Pair Repulsion
43. If the shape of a molecule is trigonal planar, what are the values of
the bond angles?
Ans. 120°
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?
Ans. bent or angular
45. 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.
46. Which of the following Lewis structures of neutral atoms is correct?
Ans. C
47. Which of the following Lewis structures of ions is incorrect?
Ans. C
48. Which of the following has the greatest electronegativity?
A. H B. Cl C. O D. F E. Na
Ans. D
49. Which of the following has the greatest electronegativity?
A. Si
B. P C. Cl
D. Ar
E. Br
Ans. C
50. In the compound CH3Cl the bond between carbon and chlorine is
A. intermolecular
B. ionic
C. nonpolar covalent D. polar covalent
Ans. D
51. 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
1. Which of the following pairs of atoms are least likely to form an ionic compound?
A. Ni, O
B. Na, F
C. Cu, Cl
D. Li, Mg
E. Li, F
Ans. D. Li, Mg
2. The bond in dinitrogen (N2) is a:
a. double bond. B. single bond. C. triple bond. D. lone pair. E. none of the above
Ans. C
3. Which of the following formulas are incorrect on the basis of simple Lewis dot
structures?
a. LiCl B. MgO C. Na2O D. CO2
E. none of these
Ans. E
4. Which of the following bonds is most polar?
a. H-F
B. H-Cl C. H-H
D. F-F E. H-I
Ans. H-F
56. Assuming reactions between the following pairs of elements, which pair
is most likely to form an ionic compound?
A. copper and tin
B. chlorine and oxygen
C. cesium and iodine
D. carbon and chlorine
E. fluorine and iodine
Ans. C
57. 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
58. What is the old name of Cu+?
A. cupric ion
B. cuprous ion
C. copper(I) ion
D. copper(II) ion
E. ferrous ion
Ans. B
59. Give the name of FeSO4 in the Stock system.
A. iron monosulfuric acid
B. iron(II) sulfate
C. iron(III) sulfate
D. ferrous sulfate
E. ferric sulfate
Ans. B
60. Assuming reactions between the following pairs of elements, which pair
is most likely to form a covalent compound?
A. lithium and iodine
B. sodium and oxygen
C. calcium and chlorine
D. copper and tin
E. carbon and oxygen
Ans. E
61. 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
62. What is the correct formula of phosphorus pentachloride?
A. PCl B. PCl3 C. PCl5 D. P2Cl5 E. P5Cl
Ans. C
63. What term describes the temperature at which a solid is converted into
a liquid?
A. critical point
B. flash point
C. sublimation point
D. melting point
E. boiling point
Ans. D
64. What term describes a solution of a compound in water that conducts an
electric current?
A. amorphous solution
B. an electrolyte solution
C. a nonelectrolyte solution
D. superconducting solution
E. isoelectric solution
Ans. B
65. How many bonding electrons are in CO2?
A. 1 B. 2 C. 3 D. 4 E. 8
Ans. E
66. How many nonbonding electrons are in CH4?
A. 0 B. 1 C. 2 D. 3 E. 8
4 62 62 A
67. How many valence electrons are in SO42-?
A. 2 B. 64 C. 32 D. 12 E. 16
Ans. C
68. According to VSEPR theory, if the valence electrons on a central atom
are 3 bond pairs and one nonbonding (lone) pair, the geometry (shape)
at this atom will be
A. linear
B. bent (angular)
C. trigonal planar
D. trigonal pyramidal
E. tetrahedral
Ans. D
69. T F In Lewis structures, the chemical symbol of an element represents
both the nucleus and the lower energy (nonvalence) electrons.
Ans. T
70. T F The name of SnO2 is tin(I) oxide.
Ans. F
71. T F The old name of iron(III) chloride is ferrous chloride.
Ans. F
72. T F The are three atoms of iodine represented in the formula NaIO3.
Ans. F
73. T F In solid NaCl, no molecules of NaCl exist.
Ans. T
74. T F Ionic solids are amorphous.
Ans. F
75. T F Molecular compounds usually involve ionic bonding.
Ans. F
76. T F As a rule, ionic compounds tend to have lower melting and boiling
points than covalent compounds consisting of small molecules.
Ans. F
77. T F In the water molecule, the oxygen atom is an exception to the
octet rule.
Ans. F
78. T F The NO2 molecule can never satisfy the octet rule.
4 74 74 T
79. T F Six electrons shared between two atoms corresponds to a bond
order of three.
4 75 75 T
80. T F Resonance occurs when two or more different, valid Lewis
structures can be drawn for a molecule+.
Ans. T
81. T F The existence of resonance makes a molecule less stable than
would otherwise be the case.
Ans. F
82. T F Because the C-H bond in methane is polar, the CH4 molecule will
also be polar.
Ans. F
83. T F Chemical bonds are intramolecular forces.
Ans. T
84. T F In determining properties such as solubility, melting point and
boiling point, intramolecular forces are more important than
intermolecular forces.
Ans. F
85. T F As a rule, a polar substance will be a good solvent for nonpolar
solutes, and vice versa.
Ans F
Filename:
Chapter4
Directory:
G:\public_html\chem120
Template:
C:\Documents and Settings\upali\Application
Data\Microsoft\Templates\Normal.dot
Title:
Chapter 3
Subject:
Author:
Upali Siriwardane
Keywords:
Comments:
Creation Date:
9/27/2004 1:51 PM
Change Number:
2
Last Saved On:
9/27/2004 1:51 PM
Last Saved By:
Upali Siriwardane
Total Editing Time:
2 Minutes
Last Printed On:
9/27/2004 1:56 PM
As of Last Complete Printing
Number of Pages:
31
Number of Words: 8,120 (approx.)
Number of Characters:
46,290 (approx.)