TEST A Page 2
Questions 51 – 57: Match each word with the BEST definition below.
51. metallic bond 52. lattice energy 53. octet rule 54. resonance
55. double bond 56. polar covalent bond 57. nonpolar covalent bond
A. A covalent bond produced by sharing one pair of electrons.
B. Atoms form bonds so they have 8 valence electrons.
C. When more than one Lewis structure can be drawn.
D. Bonded atoms share all their valence electrons in common.
E. the difference in electronegativity between the two bonded atoms is less than 0.3
AB. A covalent bond produced by sharing two pairs of electrons.
AC. Results from the attraction between positive and negative ions.
AD. A covalent bond in which the electrons are not shared equally.
AE. The energy needed to break an ionic bond.
58. How many unpaired electrons are in the Lewis dot symbol for a nitrogen atom?
a) 0; b) 1; c) 2; d) 3; e) 4
59. How many unpaired electrons are in the Lewis dot symbol for an oxygen ion (O2-)?
a) 0; b) 1; c) 2; d) 3; e) 4
60. Based on electron configuration, which ion would phosphorus most likely form?
a) P5+; b) P5-; c) P3+; d) P3-; e) P4-
61. How many electrons appear in the Lewis dot symbol for an oxygen atom?
a) 4 paired and 2 unpaired; b) 2 paired and 4 unpaired;
c) 5 paired and 1 unpaired; d) 1 paired and 3 unpaired
62. Which ion below has a noble gas electron configuration?
a) Ne-; b) I+; c) As3-; d) K2+; e) N2-
63. The oxide of which of the following metals should have the greatest lattice energy?
a) Na; b) Mg; c) Ca; d) Rb
64. Lattice energy _____ as ionic radius increases and ______as ionic charge increases.
a) decreases, increases b) increases, decreases
c) increases, increases d) decreases, decreases
65. Which of the following electron configurations corresponds to a N3- ion?
a) [He]; b) [He]2s2; c) [He]2s22p6; d) [He]2s22p3
66. What type of covalent bond is the shortest?
a) single; b) double; c) triple; d) they are all the same length
67. How many hydrogen atoms must bond to phosphorus to give it an octet of valence electron?
a) 2; b) 3; c) 4; d) 5; e) 8
68. Which atom below has the greatest electronegativity? a) Se; b) Br; c) S; d) Cl
Questions 69 –71: Using the electronegativities listed below, determine whether the bonds in the following substances are: (a) ionic; (b) polar covalent; or (c) nonpolar covalent.
Electronegativities: C 2.6 Se 2.5 Na 0.9 F 4.0 O 3.5
69. CSe2 70. NaF 71. CO2
72. The carbonate ion, CO32-, has how many total valence electrons?
a) 10; b) 12; c) 20; d) 22; e) 24
73. Of the following, which cannot accommodate more than an octet?
a) P; b) As; c) O; d) S
74. For the resonance forms of a molecule or ion:
a) one always corresponds to the actual observed structure;
b) all always correspond to the actual observed structure;
c) the actual observed structure is an average of the forms;
d) the same atoms need not be bonded to each other in all forms.
75. Which bond would be the strongest? a) single; b) double; c) triple
76. As the number of covalent bonds between two atoms increases, the distance between the atoms ______and the strength of the bond between them ______.
a) increases, increases; b) decreases, decreases
c) increases, decreases; d) decreases, increases
77. How many valence electrons do the halogens, the alkali metals, and the alkaline earth metals each have, respectively?
a) 2, 4, 6; b) 1, 5, 7; c) 8, 2, 3; d) 7, 1, 2; e) 2, 7, 4
78. A nonpolar covalent bond is unlikely when two different atoms join because the the atoms are
likely to differ in: a) polarity; b) mass; c) electronegativity; d) radius; e) atomic number.
79. An ionic bond results from the attraction between:
a) two nuclei; b) shared electrons; c) dipoles; d) oppositely charged ions; e) protons.
80. A covalent bond results from the mutual attraction of the bonded nuclei for:
a) the other nucleus; b) shared electrons; c) dipoles; d) ions; e) protons.
81. The atoms in a molecule are held together by: a) ionic bonds;
b) intermolecular forces; c) covalent bonds; d) dipole-dipole forces.
82. Which of the following is NOT true about ionic compounds:
a)they have high melting points; b) they conduct electricity when dissolved in water;
c) they are brittle; d) they are ductile.
83. Ionic compounds are ____ at room temperature.
a) solid; b) liquid; c) gas; d) can be all of the above.
84. Molecular (covalent) compounds are ____ at room temperature.
a) solid; b) liquid; c) gas; d) can be all of the above.
DRAW CORRECT LEWIS STRUCTURES FOR:
1. SCl2 2. SiO2 3. BCl3
4. PF3 5. ClF3 6. CO
7. DRAW THE THREE POSSIBLE RESONANCE STRUCTURES FOR NO3-