Chemistry 122
Exam 1
Winter 2010
January 28, 2010
Oregon State University
Dr. Robertha Howell
Dr. Richard Nafshun
Instructions: You should have with you several number two pencils, an eraser, your 3" x 5" note card, a
calculator, and your University ID Card. If you have notes with you, place them in a sealed backpack
and place the backpack OUT OF SIGHT or place the notes directly on the table at the front of the room.
Fill in the front page of the Scantron answer sheet with your last name, first name, middle initial, and
student identification number. Leave the class section number and the test form number blank.
This exam consists of 25 multiple-choice questions. Each question has four points associated with it.
Select the best multiple-choice answer by filling in the corresponding circle on the rear page of the
answer sheet. If you have any questions before the exam, please ask. If you have any questions during
the exam, please ask the proctor. Open and start this exam when instructed. When finished, place your
Scantron form in the appropriate stack and present your University ID Card to the proctor. You may
keep the exam packet, so please show your work and mark the answers you selected on it.
Please read each exam question carefully. Terms such as correct, false, unpaired, pairs, H-C-F bond angle,
H-C-H angle, greatest, and smallest are used.
1.
There are ___ unpaired electrons in a ground-state calcium ion (Ca2+).
(A)
(B)
(C)
(D)
(E)
2.
The ground-state electron configuration of a nitride ion (N3-) is:
(A)
(B)
(C)
(D)
(E)
3.
0
1
2
3
4
1s22s23s23p2
1s22s23s1
1s22s22p6
1s22s22p63s23p2
1s22s22p4
Consider the structures of NH3 and CH4 pictured below. Identify which of the following
statements is correct.
H
N
H
H
H
Ammonia
(A)
(B)
(C)
(D)
(E)
C
H
H
H
Methane
The H-N-H bond angle in ammonia is larger than H-C-H bond angle in methane
Ammonia and Methane both have tetrahedral electron geometry
The molecular geometry of ammonia is trigonal planar
The H-N-H bond angle in ammonia is equal to 109.5 ˚
Ammonia and methane are polar molecules
4.
Consider the following elements: C, N, O, F, Cl. Which of the following statements is correct?
(A) Carbon is smaller than oxygen because the carbon atom has a smaller nuclear charge
(B) Fluorine is larger than chlorine because the fluorine atom has less electron-electron repulsion
(C) Oxide ion ( O 2  ) is larger than the fluoride ( F  ) ion because F  has more protons
(D) The nitride ion has an electron configuration similar to the helium atom
(E) The oxygen molecule ( O2 ) has an oxygen-oxygen triple bond
5.
Consider Mg, Mg2+, O, and O2-. Which of the following statements is correct?
(A)
(B)
(C)
(D)
6.
Mg is smaller than Mg2+.
O2- is smaller than O.
Mg2+ is smaller than O2-.
This question is ambiguous and cannot be answered without a data table.
Consider F, O, N, C, and Mg. The atom with the greatest electronegativity is:
(A)
(B)
(C)
(D)
(E)
F
O
N
C
Mg
7.
Which one of the following equations represents the reaction between lithium and fluorine?
Li + F
Li F
Li + F
Li F
Li + F
Li + F
Li + F
Li + F
(A)
(B)
(C)
(D)
(E)
8.
Li + F
+
+
Li F
Consider a phosphorus atom in the ground-state. Which of the following statements is false?
(A)
(B)
(C)
(D)
A phosphorus atom has 15 total electrons; 5 are core electrons and 10 are valence
electrons.
The Lewis Dot Structure for a phosphorus atom has 5 electrons (dots).
There are three unpaired electrons in the phosphorus atom.
The arsenic atom is larger than the phosphorus atom.
9.
The Lewis Dot Structure of ammonia, NH3, depicts:
(A)
(B)
(C)
(D)
(E)
10.
Consider one oxygen-oxygen bond in the ozone molecule (O3). The oxygen-oxygen bond order
in the ozone molecule is:
(A)
(B)
(C)
(D)
(E)
11.
There are no lone pairs of electrons.
There is one lone pair of electrons.
There are two lone pairs of electrons.
There are three lone pairs of electrons.
There are four lone pairs of electrons.
1.00
1.33
1.50
2.00
2.66
A student (
) proposes the following two Lewis Dot Structures, shown below, for the cyanate
ion, [OCN]-. By calculating the formal charges on the atoms in both structures and considering
the electronegativity of Oxygen and Nitrogen determine which structure is the more likely
representation of the cyanate ion.
O C N
O C N
(A)
(B)
(C)
Structure 1 is the more likely configuration
Structure 2 is the more likely configuration
Both structures are equally likely.
Structure 1
Structure 2
12.
The O-C-O bond angle in the carbonate ion, CO32-, is:
(A)
(B)
(C)
(D)
(E)
13.
Silane (pictured below), also known as silicon tetrahydride and monosilane, is SiH4. The H-Si-H
bond angle is is:
(A)
(B)
(C)
(D)
(E)
14.
90
120
109.5
A little greater than 109.5
A little less than 109.5
The molecular geometry of SF6 is:
(A)
(B)
(C)
(D)
(E)
15.
90
120
109.5
A little greater than 109.5
A little less than 109.5
bent
trigonal planar
trigonal pyramidal
linear
octahedral
Consider phosphorus pentachloride, PCl5. The geometry of is PCl5:
(A)
(B)
(C)
(D)
(E)
linear
trigonal planar
trigonal pyramidal
trigonal bipyramidal
octahedral
16.
Consider the 1st ionization energy of Mg. Which of the following equations correctly represents
the 1st ionization of Mg.
(A)
(B)
17.
+
Mg
Mg + e
Mg
Mg + e
(C)
Mg + e
+
ΔH > 0
ΔH < 0
Mg
ΔH > 0
(D)
Mg
Mg + 2e
ΔH < 0
(E)
Mg
Mg + 2e
2+
2+
ΔH > 0
Consider the H2O molecule. Which one of the following statements is false?
(A)
(B)
(C)
(D)
(E)
The H2O molecule is polar
The molecular geometry of the water molecule is linear
The Lewis Dot structure of the H2O molecule has 2 lone pairs of electron on the oxygen
The Lewis Dot diagram of a hydrogen atom has 1 dot (electron)
Oxygen is more electronegative than hydrogen
18. Consider the molecule below.
There are ______ carbons that have a sp hybridization schemes and _______ carbons that have a sp2
hybridization schemes.
(A)
(B)
(C)
(D)
(E)
19.
zero, seven
zero, five
two, four
three, four
three, five
There are ________ resonance forms for the nitrate ion (NO3-).
(A)
(B)
(C)
(D)
(E)
0
1
2
3
4
20. Consider the molecule below and identify the correct statement.
(A)
(B)
(C)
(D)
(E)
21.
Consider C2H2, C2H4, and C2H6. Which of these has the strongest carbon-carbon bond?
(A)
(B)
(C)
22.
There are 15 sigma-bonds and 4 pi-bonds
There are 11 sigma-bonds and 4 pi-bonds
There are 15 sigma-bonds and 5 pi-bonds
There are 11 sigma-bonds and 5 pi-bonds
There are 7 sigma-bonds and 4 pi-bonds
C2H6 because single bonds are longer than both double and triple bonds
C2H4 because the two carbons share 4 electrons to form a double bond
C2H2 because triple bonds are stronger than single and double bonds
Consider MO (Molecular Orbital Theory). For the F2 molecule, there are ___________ electrons
in the π2p* anti-bonding orbitals?
(A)
(B)
(C)
(D)
(E)
0
1
2
3
4
23.
Consider MO (Molecular Orbital Theory). The N2+ (a positive one charge) ion is:
(A)
(B)
(C)
(D)
(E)
24.
Molecular orbital theory predicts that nitic oxide, NO, has a bond order of:
(A)
(B)
(C)
(D)
(E)
25.
paramagnetic
diamagnetic
tetramagnetic
penta-magnetic
tiger-magnetic
1.0
1.5
2.0
2.5
3.0
Because of Chemistry 122...
(A)
(B)
(C)
(D)
(E)
I have become very popular
I have laughed more times in the past four weeks than I have in the previous four years
I have an awesome Facebook page
I have begun questioning authority
I have milked more money out of my parents than ever before
[Any response will receive full credit; even no response.]