Name ____________________________
School _______________________
COLLEGE IN HIGH SCHOOL
2009 - 2010
Exam III
Tuesday, March 16 2010
INSTRUCTIONS:
DO NOT TEAR ANY PAGES OFF YOUR EXAM
PRINT YOUR NAME AND SCHOOL AT THE TOP OF THIS PAGE.
The exam contains 17 questions. You must answer a total of 15 questions, as follows. You must
attempt Questions #1 – 8 and #17. For the multiple-choice Questions #9 – 16, you must attempt
any 6 and no more than 6 of these 8 questions. You must indicate clearly which 2 questions you
are omitting by entering J as the response for each of these two questions.
The multiple-choice questions are worth 6 points each and should be answered on the machinescored sheet, using a #2 pencil. Be sure to write and code in your name on this sheet. Write your
last name, then a space, then your first name. Do all your working on the exam sheets. For
question 17 (10 points), you should write your answers in the spaces provided on the exam
sheets. The last few points will be given for your written answers to the questions marked ** in
the exam.
TURN IN THE WHOLE EXAM and the MACHINE-SCORED SHEET.
USEFUL INFORMATION
c = 
c = 3.00 x 108 m/s
E = h
h = 6.63 x 10-34 J.s
RH
n2
1 Hz = 1 s-1
En = -
OR
En = RH -
RH
n2
RH = 2.179 x 10-18 J
A periodic chart is on the reverse of this sheet
GOOD LUCK!
1. A student calculated the wavelength (in m), frequency (in Hz), and photon energy (in J) of
a certain type of ultra-violet electromagnetic radiation. The teacher found three correct
answers on the sheet of paper: 1.18 x 1015, 7.83 x 10-19 and 2.54 x 10-7. Which of these values
is the wavelength, which is the frequency and which is the photon energy?
*** Show your work or give your reasoning
A)
B)
C)
D)
E)
F)
Wavelength, m
1.18 x 1015
1.18 x 1015
7.83 x 10-19
7.83 x 10-19
2.54 x 10-7
2.54 x 10-7
Frequency, Hz
7.83 x 10-19
2.54 x 10-7
1.18 x 1015
2.54 x 10-7
1.18 x 1015
7.83 x 10-19
Photon Energy, J
2.54 x 10-7
7.83 x 10-19
2.54 x 10-7
1.18 x 1015
7.83 x 10-19
1.18 x 1015
2. (i) Determine the energy difference in J between the n = 5 and n = 7 quantized levels of the
H atom. (ii) Hence or otherwise, determine the wavelength in m of light emitted when the
electron in the H atom jumps from n = 7 to n = 5.
*** Show your work
(i)
A) 5.45 x 10-19J
B) 5.45 x 10-19J
C) 9.08 x 10-20J
D) 9.08 x 10-20J
E) 1.96 x 10-2J
F) 1.96 x 10-2J
G) 4.27 x 10-20J
H) 4.27 x 10-20J
(ii)
3.65 x 10-7m
2.74 x 106m
2.72 x 10-11m
1.37 x 1014m
2.74 x 106m
6.53 x 10-11m
4.66 x 10-6m
6.44 x 1013m
3. Which one statement (A) – (D) concerning the photoelectric effect is NOT correct? If all
are correct, select response (E).
A) The photoelectric effect refers to the ejection of electrons from a metal when illuminated
with a suitable form of light.
B) Light of low intensity does not cause electron ejection, whereas light of high intensity
does cause electron ejection.
C) If, for a certain metal, red light does not cause electron ejection, and blue light does cause
electron ejection, then UV light will also cause electron ejection.
D) From the study of the photoelectric effect, it was concluded that light consists of photons,
each with an energy E = h.
E) All the statements (A) – (D) are correct.
4. Which of the following subshells contain(s) an orbital with ml = -2? Select all which
apply.
4s
3d
4d
5f
2p
2s
A) 2s and 2p
B) 3d only
C) 4s, 3d and 4d
D) 3d, 4d and 5f
E) All of them
F) None of them
5. Consider the electron configuration of the P atom: 1s2 2s2 2p6 3s2 3p3. Which one of the
following statements is completely correct?
A) The 3p orbital contains 3 electrons
B) The 3p shell contains 3 electrons
C) The 3p shell is exactly half-full of electrons
D) The 3p subshell contains 3 electrons
E) Three of the 3p orbitals are full; the other three are empty
6. Which is the correct valence electron configuration of Sn? (If a response includes any core
electrons, that response is incorrect!)
*** Draw an orbital diagram for the valence electrons in the Sn atom
A) 5s2 5p2
B) 4s2 3p2
C) 5s2 5d10 5p2
D) 4d12
E) [Kr] 4d10 5p2
7. In which pair does the first species have a larger atomic radius than the second?
A) Mg and Sr
B) Al and Al3+
C) I and ID) Ge and K
E) Kr and Rb
8. Which one of the following is the correct set of values for the ionization energy (in
kJ/mol), the electron affinity (in kJ/mol) and the atomic radius (in pm) of the sulfur atom?
*** Give your reasoning (i.e. some logic is involved)
A)
B)
C)
D)
E)
F)
IE (kJ/mol)
995
995
105
105
-200
-200
EA (kJ/mol)
105
-200
-200
995
995
105
Radius (pm)
-200
105
995
-200
105
995
9. A compound AB3 has polar covalent bonds, with a small positive charge, +, on atom A.
Which of the following statements is/are correct?
1. Element A is definitely a metal and B is a non-metal
2. AB3 is definitely a molecular compound
3. The electronegativity of atom B is definitely larger than that of atom A
A) 1 only
F) 2 and 3
B) 2 only
C) 3 only
D) 1 and 2
G) All of them
H) None of them
E) 1 and 3
10. Determine the total number of valence electrons in the SO32- ion, i.e. the number of
electrons used in the Lewis structure.
A) 8
G) 34
B) 14
H) 36
C) 22
D) 24
E) 26
F) 32
11. Which one statement concerning covalent bonding is NOT correct?
A) A C=C double bond is typically longer than a C-C single bond.
B) A covalent bond involves sharing of electrons between the bonding atoms
C) A covalent bond involves overlap of atomic orbitals on the bonding atoms
D) A single covalent bond contains two electrons
E) A C=C double bond has a larger bond dissociation energy than a C-C single bond
12. Determine the enthalpy change for the reaction:
C2H4(g) + Br2(g) → C2H4Br2(g), ΔH = ?
Given the following bond dissociation energies in kJ/mol: C-H: 411; C=C: 602; C-C: 346;
Br-Br: 190; C-Br: 285. Hint: C2H4 contains a double bond; C2H4Br2 contains only single
bonds.
A) +61 kJ
B) -61 kJ
C) +984 kJ
D) -984 kJ
E) +161 kJ
F) -161 kJ
G) +124 kJ
H) -124 kJ
13. Which one response gives the correct assignment of the three species?
Ca
A) Ionic
B) Ionic
C) Metallic
D) Molecular
E) Metallic
CS2
Ionic
Molecular
Ionic
Metallic
Molecular
Ca(OH)2
Metallic
Molecular
Molecular
Metallic
Ionic
14. With reference to VSEPR theory, which assignment of the electron arrangement or the
molecular geometry around the central atom is NOT correct, for the given number of single
bonds and lone pairs around the central atom?
A) 2 bonds and 2 lone pairs: molecular geometry is linear
B) 3 bonds and 1 lone pair: molecular geometry is trigonal pyramidal
C) 4 bonds and 0 lone pairs: electron arrangement is tetrahedral
D) 5 bonds and 0 lone pairs: electron arrangement is trigonal bipyramidal
E) 2 bonds and 1 lone pairs: molecular geometry is bent
15. Which of the following is/are polar molecules?
CH4
CH3F
CH2F2
CHF3
*** Give your reasoning
CF4
A) CH4 and CF4 only
B) CH3F and CHF3 only
C) CH3F, CH2F2 and CHF3
D) CH4, CH2F2 and CF4
E) All of them
F) None of them
16. Which one of the following has sp2 hybridization on the central atom? Remember that
Lewis structures do not necessarily show the correct geometry.
A) H
P
B)
H
O
C
O
C)
H
O
H
H
H
D)
O
S
E) H
O
C
H
H
17. (10 points) (a) Draw the Lewis structure of the phosphate ion, PO43-.
(b) Then, explain carefully why the phosphate ion cannot have a 1- charge, i.e. explain why a
valid Lewis structure cannot be drawn for PO4-.
c) Draw a Lewis structure of the NH4+ ion
d) Then, draw a Lewis structure of ammonium chloride, NH4Cl.
e) Here is the Lewis structure of formic acid:
H
C
O
O
H
Hence draw a Lewis structure of the formate ion, HCO2-.
2009 – 10: ANSWER KEY EXAM 2
1
E
2
G
3
B
4
D
5
D
6
A
7
B
8
B
9
F
10
E
11
A
12
H
13
E
14
A
15
C
16
D
Question #17.
a)
O
[
O
P
]3-
O
or 4 single bonds
O
b) PO4- has a total of 30 valence electrons, insufficient to put an octet of electrons around
each oxygen atom.
c, d)
H
[ H
N
H
H
]+
[ H
N
H
H
(c)
(d)
H
]+
Cl-
e) The H atom is lost from the O atom to form the formate ion.
[ H
C
O
]-
O
There is no need for the student to show the other resonance form.