Conversation overheard between a cation and an anion…

DR. KATHY BURKE
FALL 2009-2 nd half
THIS EXAM CONSISTS OF
24 QUESTIONS ON 8 PAGES
CHEM 50 Section 7
HOUR EXAM 2
November 6, 2009
NAME___________________________
(Please Print, Last Name First)
QUESTIONS
Pages 3 & 4
Page 5
GRADING
POINTS
50 pts
30 pts
SCORE
________
________
I agree to waive the Buckley amendment and have my exam
returned to me during a lecture or help session.
Signed_________________________
(If not signed, an appointment will have to be made to receive
your paper privately.)
Page 6
Page 7
TOTAL
20 pts
ec 5 pts
105 pts
________
________
REMINDER! Final exam is on Wednesday, December
16, 2:15-4:15 p.m. Please make your travel plans
accordingly.
________
THE ANSWER KEY TO THIS EXAM WILL BE POSTED ON
BULLETIN BOARD #6 IN THE HALLWAY EAST OF
ROOM 1002 GILMAN AND ON THE CHEM 50 WEBSITE.
+
-
Conversation overheard between a
cation and an anion…
Cation to Anion: Yes, I gave you my electron!
Anion to Cation: Are you sure
Cation to Anion: Yes, I’m positive!

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1.
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2

Part 1. (50 pts) The first part of this exam is multiple choice. Each question 1-20 is worth 2.5 points. Please use a #2
pencil to mark your answer for questions 1-20 of the following on the bubble sheet that has been provided to you. The
bubble sheets will not be returned to you. You should also indicate your answers on pages 3 and 4 for your own reference
so that you know which answers you chose. Only the bubble sheet will be graded not pages 3 and 4 of the test booklet.
1. Elements are arranged on the periodic table in order of increasing __________________.
a. atomic mass b. atomic number c. number of neutrons
2. An ____________ is ____________ than the neutral atom from which it is formed.
a. anion, larger b. anion, smaller
3. What is the charge on a gallium ion that contains 28 electrons
a. 3+ b. 28- c. 5- d. 1+ e. none of the above
Use the following table to answer questions #4 and #5.
Protons Electrons neutrons
I. 7 7 7
II. 10 7 10
III. 7 10 7
IV. 7 7 8
4. Isotopes of one another.
a. I, II b. I, III c. I, IV d. II, III e. II, IV
5. One is the ion of the other.
a. I, II b. I, III c. I, IV d. II, IV e. III, IV
6. Which of the following elements is a metalloid
a. B b. C c. Ga d. Se e. In
7. Which is NOT a neutral atom Please circle the letter of your answer.
# protons # electrons # neutrons
a. 6 6 8
b. 9 10 10
c. 8 8 7
d. 10 10 10
8. Which is larger between the two below, a or b ____________
a. #p=12, #e - =10; #n=12 b. #p=12, #e - =12; #n=12
9. An electron in which energy level has the highest energy
a. n=3 b. n=5 c. n=2 d. n=4
10. An electron in which energy sublevel has the highest energy
3

a. 3s b. 3p c. 3d d. 4s
11. Which sublevel can hold a maximum of ten electrons
a. s b. p c. d d. f
12. Which orbital has a dumbbell shape
a. s b. p c. d d. f
13. Which one of the following should have 2 significant figures in the answer
a. 0.1579 x 0.000236 x 157.76 = _____ s.f. b. 950 x 4.120 x 788 = _____ s.f.
4.53 x 0.01 0.00712
14. Energy levels within the atom are arranged like rungs of a ladder. Looking at the energy level “ladder” shown below,
for which change in levels would the least energy be required
a. n=2—>n=3 b. n=4—>n=5 c. n=1—>n=2
15. One molecule of ____ contains the largest total number of atoms.
a. S 8 b. C 10 H 8 c. Al 2 (SO 4 ) 3 d. Na 3 PO 4 e. Cl 2
16. Which is the largest atom
a. Sr b. Al c. N
17. Which atom has the highest ionization energy
a. Sr b. Al c. N
18. Which element is the most reactive
a. Al b. Mg c. Ca
19. Which element is most metallic
a. Si b. P c. Ga
4

20. Which ion is smaller
a. Ga +3 b. P -3
21. (4 pts) a. Please underline the zero(s) that is/are significant in the following number.
0.0099959010
b. Round to 3 significant figures. 0.0099959010 cm __________________
22. (5 pts) Fill in the 4 blank boxes in the following table. For the box marked with the (*), please put both the mass
number and the chemical symbol for the atom/ion. Please print your answers.
*
32 P -3
Protons 40
Electrons 38
Neutrons 51
23. (10 pts)
a. What is the complete electron configuration for As ________________________________
b. Circle the valence electrons for As in the electron configuration that you have written.
c, Write the electron configuration for the arsenic (As) ion. __________________________________
d. To which noble gas is the As ion isoelectronic __________
e. Which element has the electron configuration 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 3 ____________
24. (7 pts)
a. How many oxygen (O) atoms are in one molecule of calcium acetate Ca(C 2 H 3 O 2 ) 2 _________
b. Write the chemical formula for a molecule of penicillin that has 16 atoms carbon (C), 18 atoms hydrogen (H), 2 atoms
nitrogen (N), and 5 atoms oxygen (O), and 1 atom of sulfur (S) ___________________________
c. Seven elements are found in nature as diatomic elements. (Remember, a diatomic element must have how many
atoms) Write the chemical formula for one of the diatomic elements. _________
25. (4 pts)
a. What is the charge on an ion of calcium, Ca Include both the sign and the number. _____
b. What is the charge on an ion of nitrogen, N Include both the sign and the number. _____
c. What is the chemical formula for the ionic compound that you expect to form between an ion of calcium and nitrogen
For example, as we saw in class, the chemical formula for the ionic compound between an ion of sodium and chlorine is
NaCl.
5

Chemical formula for the compound between an ion of calcium and an ion of nitrogen: _____________________
26. (15 points) Please use the symbols for the chemical elements in the following periodic table to answer this question.
There will be only one correct answer for each of the statements a-o. Please write the symbol of the correct element best
described by the question.
1A
H
2A 3A 4A 5A 6A 7A
N
Mg Al P
Ni Ge Se
8A
Ne
Rb Y I
Ba Hg Pb
_____ a. A metal with three valence electrons.
_____ b. Has eight 3d electrons.
_____ c. Has two valence electrons.
_____ d. A nonmetal to the left of the stair step.
_____ e. A metalloid.
_____ f. A halogen.
_____ g. A noble gas.
_____ h. A period two element with five valence
electrons.
_____ i. An alkali metal.
_____ j. An alkaline earth metal in period 6.
_____ k. Has six valence electrons.
_____ l. Electron configuration ends in 4d 1 .
_____m. A metal in Group 4A.
_____ n. Has valence electron configuration 3s 2 3p 3 .
_____ o. Has ten “d” electrons.
27. (5 pts) How many megagrams are in 1.316 milligrams
You only need to show the set-up of the work for how you would calculate the answer; you do NOT need to calculate the
answer; please use the “gfu” method and show all work for full credit; include the units and number of significant figures
for your final answer.
____________ units
____________ significant figures
6

Extra credit. (5 pts) A hybrid car has both a gasoline-powered engine and an electric motor. The car has an EPA
gasoline mileage rating of 70.0 mile/gallon on the highway. What is this rating in cm/L
Helpful information: 1 in = 2.54 cm; 1.057 qt = 1L; 1 mile = 5280 feet; 4 qt = 1 gallon
You only need to show the set-up of the work for how you would calculate the answer; you do NOT need to calculate the
answer; please use the “gfu” method and show all work for full credit; include the units and number of significant figures
for your final answer.
____________ units
____________ significant figures
7

8
Periodic Table of the Elements
103
Lr
(260)
102
No
(259)
101
Md
(258)
100
Fm
(257)
99
Es
(252)
98
Cf
(251)
97
Bk
(247)
96
Cm
(247)
95
Am
(243)
94
Pu
(244)
93
Np
(237)
92
U
238
91
Pa
231
90
Th
232
71
Lu
175
70
Yb
173
69
Tm
169
68
Er
167
67
Ho
165
66
Dy
162
65
Tb
159
64
Gd
157
63
Eu
152
62
Sm
150
61
Pm
(145)
60
Nd
144
59
Pr
141
58
Ce
140
8A
18
7A
17
6A
16
5A
15
4A
14
3A
13
Lanthanides
Actinides
109
Une
(266)
108
Uno
(265)
107
Uns
(262)
106
Unh
(263)
105
Ha
(262)
104
Rf
(261)
89
Ac
227
88
Ra
226
87
Fr
(223)
83
Bi
209
82
Pb
207
81
Tl
204
80
Hg
201
79
Au
197
78
Pt
195
77
Ir
192
76
Os
190
75
Re
186
74
W
184
73
Ta
181
72
Hf
178
57
La
139
56
Ba
137
55
Cs
133
51
Sb
122
50
Sn
119
49
In
115
48
Cd
112
47
Ag
108
46
Pd
106
45
Rh
103
44
Ru
101
43
Tc
(98)
42
Mo
95.9
41
Nb
92.9
40
Zr
91.2
39
Y
88.9
38
Sr
87.6
37
Rb
85.5
86
Rn
(222)
85
At
(210)
84
Po
(209)
52
Te
128
53
I
127
54
Xe
131
36
Kr
83.8
35
Br
79.9
34
Se
79.0
33
As
74.9
32
Ge
72.6
31
Ga
69.7
30
Zn
65.4
29
Cu
63.5
28
Ni
58.7
27
Co
58.9
26
Fe
55.8
25
Mn
54.9
24
Cr
52.0
23
V
50.9
22
Ti
47.9
21
Sc
45.0
20
Ca
40.1
19
K
39.1
18
Ar
39.9
17
Cl
35.4
16
S
32.1
15
P
31.0
14
Si
28.1
13
Al
27.0
2
He
4.00
10
Ne
20.2
9
F
19.0
8
O
16.0
7
N
14.0
6
C
12.0
5
B
10.8
8B
2B
12
1B
11
10
9
8
7B
7
6B
6
5B
5
4B
4
3B
3
12
Mg
24.3
11
Na
23.0
4
Be
9.01
3
Li
6.94
2A
2
1A
1
1
H
1.01