Term test #1 (50 points)
Friday, May 27, 2011
You have 50 minutes to complete this test and 7 questions.
A calculator and periodic table may be used as required.
For all questions where an image or diagram would be useful, add a drawing, image or diagram.
Name:____________________________________
Student ID________________________________
2
Chem 222 Intro to Inorganic Chemistry
Question
Total Mark
1
5
2
6
3
9
4
10
5
7
6
10
7
3
Total
50
Grade
Chem 222 Intro to Inorganic Chemistry
3
1. a (2 points) On the following schematic of a periodic table, place a single arrow (head of the arrow being
the larger absolute value) representing the general trends in:
a) anion radius (assume all elements can form anions)
b) Zeff
c) metallic character
d) ionization energy
1. b (3 points) Sketch a figure that shows the SPECIFIC trends in the first ionisation energy across the
second row of the periodic table (Li, Be, B, C, N, O, F, Ne)
Chem 222 Intro to Inorganic Chemistry
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2. (4 points) For each of these pairs of compounds, circle the one with the greatest dipole (difference in
electronegativity between the two atoms). Briefly justify your answers and include a drawing to depict the
difference in electronegativity. Note that both H2O and H2S have a bent geometry and include that in your
drawing.
(a)
HF
HCl
(b)
H2O
H2S
2.(c) (2 points) What are the differences between JJ Thompson’s Plum Pudding model and the Rutherford
model of the atom?
Chem 222 Intro to Inorganic Chemistry
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3. (9 points) (a) Label the orbitals and add the electrons to the following energy level diagrams to show the
ground state electron configuration of carbon and fluorine and fluoride (C, F, F-).
(b) Identify the orbital that has n = 3 and l = 1. Identify the element, assuming that there is 1 electron in the
orbital and the species is neutral.
(c) Identity the orbital that has n = 3 and l = 2 and identify the element, assuming there are 2 electron in the
orbital and the species has a +1 charge.
(d) Sketch the 3px and 3dxy orbitals. You may use any orientation for the axis, but they must be clearly
labeled.
Chem 222 Intro to Inorganic Chemistry
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4. (a) (4 marks) For a 3s orbital, fill in the following axes and label any nodes.
4 (b) (6 marks) Use Slater’s rules to calculate the effective nuclear charge felt by a 3p electron in Fe. Would
this be greater or less (actual values not required) than the charge felt by the 2s electron of Fe?
7
Chem 222 Intro to Inorganic Chemistry
5a (2 marks) For the following series of atoms or ions, circle the one with the smallest radius or state that it is
not possible to determine which is smallest.
a. Kr He
b. I
-
Ne
Ar
-
Br- F (please note that F does not have a charge)
Cl
c. Te2+
Te2-
d. Na+
Te
Mg2+
Ne
F-
O2-
5b (5 marks) Identify and name the following orbitals and list n, l, ml and ms values for them in the supplied
graph. In some cases there may be more than one possible value so select one valid value. Assume orbital a
(all three figures depict the same orbital) has one electron in it and orbital b has 2 electrons and the first
electron has a spin of +1/2. Give a ms value for the single electron in a) and the second electron in b)
Name
a)
n
l
b)
ml
ms
Chem 222 Intro to Inorganic Chemistry
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6a (6 marks) Calculate the Zeff of the outermost electron in molybdenum and in tungsten. When taking into
account the n values as well, what should this mean in terms of the expected relative atomic radius and
ionisation energy of the two elements?
6b (4 marks) The covalent radius of molybdenum is actually almost identical to that of tungsten. Discuss two
reasons why this is the case.
This corresponds to a contraction in radius that is observed for elements in the sixth period (relative to that
predicted by Schrödinger’s wave equation). For these heavier atoms, relativistic effects on the innermost
core electrons result in a decreased orbital size, particularly for the s and p orbitals.
In addition to this relativistic phenomenon, the 6th period transition metals experience the “lanthanoid
contraction”: the electrons in W’s filled 4f orbitals are extremely poor at shielding the 6s and 5d electrons,
so the Zeff felt by these electrons is large enough to reduce the covalent radius of W to approximately the
same value as that of Mo.
Chem 222 Intro to Inorganic Chemistry
7 (3marks) Classify the following bonds as ionic, covalent or polar covalent.
NaF
MgO
CH
CCl
CF
OH
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