chem 1 test 5

95. Which response includes all of the molecules listed that have the same molecular geometry as electronic geometry, and only those molecules? BCl3, AsF5, NF3, H2S

a

9. A police officer is measuring traffic speed with radar operating at 1.0 × 109 Hz. What is the wavelength of this electromagnetic energy?

a 0.30 m

113. What is the bond order for HF-?

a 0.5

11. What is the wavelength in Ångstroms of radiation used by an x-ray technician, with a frequency of 6.00 × 1018 s−1?

a 0.50 Å

4. An atom of the 40Ar isotope contains ____ protons.

a 18

14. An alpha particle of mass 4.0026 amu has a velocity of 10.0% of the speed of light. What is its de Broglie wavelength (in m)?

a 3.32 × 10−15 m

108. Which response lists all the following diatomic ions that are diamagnetic? B+2, B22+, C22+, C22-, O2-, O22-

a B22+, C22-, and O22-

96. Which species is incorrectly matched with bond angles?

a NCl3 120°

110. Which response lists only the species that have zero bond order? Li2, Ne2, C2+, He2, F22-

a Ne2, He2, and F22-

98. Which of the following statements about Molecular Orbital theory is not true?

a Pi molecular orbitals are always antibonding orbitals.

99. Which statement is false? A sigma molecular orbital

a may result from side-on overlap of p atomic orbitals.

81. For AsF3, the electronic geometry is ____ and the molecular geometry is ____.

a tetrahedral, trigonal pyramid

12. Radio waves are very low energy forms of electromagnetic radiation. What is the energy of a photon of radio waves with a wavelength of 150. m?

b 1.33 × 10−27 J

104. Draw the molecular orbital diagram for O2. The number of unpaired electrons is ____.

b 2

5. Consider the 40Ar isotope. An atom of this isotope contains ____ neutrons.

b 22

111. What is the bond order for each of the following species and which one would be predicted to have the shortest bond length? N2, N2−, N2+

b 3 2.5 2.5 N2

76. Which of the following is a false statement about BF3?

b BF3 has trigonal pyramidal electronic geometry.

114. What is the most stable heteronuclear diatomic species?

b CN-

91. What is the hybridization of a carbon atom involved in a double bond?

b sp2

115. If a species that is represented by valence bond theory as two or more resonance structures, the molecular orbital description involves

b the simultaneous overlap and mixing of the pz atomic orbitals.

100. The in-phase overlap of the 2p orbitals forms ____ sigma molecular orbitals and ____ pi molecular orbitals.

c 1, 2

2. The atomic number of a certain element is 19, and its atomic weight is 39. An atom of the element contains ____ protons, ____ neutrons, and the chemical symbol for the element is ____

c 19, 20, K

112. What is the bond order for NO-?

c 2

105. What is the bond order for N2?

c 3

13. One of the spectral lines in the emission spectrum of mercury has a wavelength of 6.234 × 10−7 m. What is the frequency of the line?

c 4.81 × 1014 s−1

75. Which one of the following molecules has only 120° bond angles?

c BI3

102. The molecular orbital electron configuration given below is for what neutral homonuclear diatomic molecule?

c C2

40. Arrange the following elements in order of decreasing first ionization energy. F, Be, O, N, C

c F > N > O > C > Be

107. What diatomic molecule and/or ion(s) would have the molecular orbital electron configuration given below?

c F2 and O22-

85. Which of the following molecules has the smallest bond angle(s)?

c H2O

84. Which one of the following is a nonpolar molecule with polar bonds?

c PF5

77. Consider the following statements about BCl3 molecules. Which statement is false?

c The Cl-B-Cl bond angles are 109.5°.

90. Which of the following statements about molecules with octahedral electronic geometry is false?

c The bond angles are 90o, 120o or 180o.

86. What is the hybridization of the oxygen atom in H3O+?

c sp3

82. The electronic geometry of the central atom in PCl3 is ____.

c tetrahedral

3. Give the number of protons, neutrons, and electrons in the ion.

d 16 p, 18 n, 18 e

92. Chose the following false statement.

d A triple bond may consist of one sigma bond and two pi bonds or of two sigma bonds and one pi bond.

71. Which one of the following statements about compounds or polyatomic ions of the A group elements is false?

d All molecules in which the central element is sp3d2 hybridized have octahedral molecular geometry.

74. Which of the following molecules has 120° bond angles?

d BCl3

80. Which one of the following molecules is polar?

d CH2F2

10. The amount of energy possessed by a photon is all of the following except?

d Is inversely proportional to frequency.

79. Which one of the following molecules is polar?

d NCl3

87. Which of the following molecules is sp3 hybridized at the central atom and has bent molecular geometry?

d OF2

83. Which of the following statements about PI3 is false?

d The bond angles are slightly larger than 109.5o.

88. Which of the following molecules has three lone pairs of electrons on the central atom?

d XeF2

106. What is the bond order for Ne2?

d zero

8. What is the frequency of light of wavelength 7000 Å?

e 4.29 × 1014 s−1

94. Choose the species that is incorrectly matched with the electronic geometry about the central atom.

e BH4- trigonal bipyramidal

101. Which statement is false?

e No two molecular orbitals for any molecule ever have the same energy.

93. Choose the species that is incorrectly matched with the electronic geometry about the central atom.

e PF3 pyramidal

78. Which statement concerning the ion, SO42-,is true?

e The hybridization of the S atom is sp3.

44. Which ion has the smallest radius?

e Tl

89. Which one of the following is a polar molecule with nonpolar bonds?

e none of these

1. The difference between the mass number of an atom and the atomic number of the atom is always equal to ____.

e the number of neutrons in the nucleus

109. What is the bond order for B22+?

e zero