NAME:____________________________
Summer 2006
Chemistry 1000 Practice Test #2
INSTRUCTIONS:
1.
Student Number:______________________
____/ 50 marks
1) Please read over the test carefully before beginning. You should have
4 pages of questions, and a periodic table (5 pages total).
2) If your work is not legible, it will be given a mark of zero.
3) You may use a calculator.
4) You have 50 minutes to complete this test.
(a)
For each of the questions below, show both the atomic orbitals (pre-overlap) and the
resulting molecular orbitals.
[6 marks]
Draw the π and π* orbitals formed when two p orbitals overlap.
(b)
Draw the σ and σ* orbitals formed when two p orbitals overlap.
(c)
How many planar nodes does each of these molecular orbitals have?
π has ____ nodes
σ has ____ nodes,
π* has ____ nodes
σ* has ____ nodes
NAME:____________________________
2.
Student Number:______________________
Complete the following table. Where charge(s) are necessary, place them on the
appropriate atom(s) in the Lewis electron dot structure.
[10 marks]
Formula
CO32-
SeF2
SeF6
Lewis Electron Dot Structure
Molecular Shape
Predicted
Bond Angle
NAME:____________________________
Student Number:______________________
3.
(a)
[8 marks]
Draw a valid Lewis dot structure for SO2.
(b)
What is the average S-O bond order for SO2?
(c)
Calculate the partial charge on the sulfur atom in SO2, and the average partial charge on
an oxygen atom in SO2. (χS = 2.6, χO = 3.5)
4.
Is the molecule BCl3 polar or nonpolar? Provide evidence by showing the shape, dipoles
and the approximate direction of the net dipole.
[4 marks]
5.
The structural formula of glycine is shown below. Name the hybrid orbital set used by
each ‘central’ atom.
[4 marks]
H
H
O
N
C
C
H
H
O
H
NAME:____________________________
6.
Student Number:______________________
The structural formula of formaldehyde (CH2O) is shown below.
[8 marks]
H
O
C
H
(a)
Name the hybrid orbital set used by C.
(b)
Name the hybrid orbital set used by O.
(c)
Consider the C–O bond according to valence bond theory. Use the pictures below as
skeletons on which to draw the atomic orbitals involved in bonding and the bonding
molecular orbitals formed for the C–O bond only.
(Choose whichever view will give the clearest picture of the orbitals. Please use a
different picture for each molecular orbital – you may draw another copy of a view if
necessary.)
atomic orbital(s)
molecular orbital(s)
H
O
C
H
O
C
H
O
(d)
C
H
H
top view
H
O
C
H
H
Label each molecular orbital drawn in part (c) to indicate the type of bond.
side view
NAME:____________________________
7.
(a)
Student Number:______________________
[10 marks]
Draw a molecular orbital correlation diagram for the valence orbitals of B2.
Be sure to: (i) label each orbital (with its name),
(ii) show the relative energies of the orbitals, and
(iii) include the valence electrons on your diagram.
(b)
Calculate the bond order for the B-B bond in B2 according to molecular orbital theory.
(c)
Give the complete electron configuration for B2 (including core and valence electrons).
(d)
Is B2 paramagnetic or diamagnetic? Briefly, justify your answer.
Chem 1000 Standard Periodic Table
1
18
4.0026
1.0079
He
H
2
2
13
14
15
16
17
6.941
9.0122
10.811
12.011
14.0067
15.9994
18.9984
Li
Be
B
C
N
O
F
Ne
3
22.9898
4
24.3050
5
26.9815
6
28.0855
7
30.9738
8
32.066
9
35.4527
10
39.948
1
20.1797
Na
Mg
11
39.0983
12
40.078
3
4
5
6
7
8
9
10
11
12
44.9559
47.88
50.9415
51.9961
54.9380
55.847
58.9332
58.693
63.546
65.39
K
Ca
Sc
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
Ga
Ge
As
Se
Br
Kr
19
85.4678
20
87.62
21
88.9059
22
91.224
23
92.9064
24
95.94
26
101.07
27
102.906
28
106.42
29
107.868
30
112.411
31
114.82
32
118.710
33
121.757
34
127.60
35
126.905
36
131.29
Rb
Sr
37
132.905
38
137.327
Cs
Ba
55
(223)
56
226.025
Fr
87
Ra
Y
39
La-Lu
Ac-Lr
88
P
S
Cl
Ar
15
74.9216
16
78.96
17
79.904
18
83.80
Zr
Nb
Mo
Tc
Ru
Rh
Pd
Ag
Cd
In
Sn
Sb
Te
I
Xe
41
180.948
42
183.85
43
186.207
44
190.2
45
192.22
46
195.08
47
196.967
48
200.59
49
204.383
50
207.19
51
208.980
52
(210)
53
(210)
54
(222)
Hf
Ta
W
Re
Os
Ir
Pt
Au
72
(261)
73
(262)
74
(263)
75
(262)
76
(265)
77
(266)
78
(281)
79
(283)
Rf
Db
Sg
105
106
138.906
140.115
140.908
144.24
La
Ce
Pr
Nd
57
227.028
58
232.038
59
231.036
60
238.029
Ac
Si
14
72.61
40
178.49
104
89
25
(98)
Al
13
69.723
Th
90
Pa
91
U
92
Bh
107
Hs
Mt
Dt
Hg
Tl
Pb
Bi
Po
At
80
81
82
83
84
85
174.967
Rg
108
109
110
111
(145)
150.36
151.965
157.25
158.925
162.50
164.930
167.26
168.934
173.04
Pm
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu
61
237.048
62
(240)
63
(243)
64
(247)
65
(247)
66
(251)
67
(252)
68
(257)
69
(258)
70
(259)
71
(260)
Np
93
Pu
94
Am
95
Cm
96
Rn
86
Bk
97
Cf
98
Es
99
Fm
100
Md
101
No
102
Lr
103
Developed by Prof. R. T. Boeré