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Chapter 7 Review Questions
Question 1 is not from a previous exam but was written based off of a recent pervious exam question.
We will go over this one in class on Tuesday!
First Ionization
Energy (kJ mol-1)
Element 1
Element 2
Element 3
Element 4
1251
496
738
1000
Second Ionization
Third Ionization
-1
Energy (kJ mol )
Energy (kJ mol-1)
2300
4560
1450
2250
3820
6910
7730
3360
1. The table above shows the first three ionization energies for atoms of four elements from the third
period of the periodic table. The elements are numbered randomly. Use the information in the table
to answer the following questions.
a.
b.
c.
d.
e.
f.
Which element is most metallic in character? Explain your reasoning.
Identify element 3. Explain your reasoning.
Write the complete electron configuration for an atom of element 3.
What is the expected oxidation state for the most common ion of element 2?
What is the chemical symbol for element 2?
A neutral atom of which of the four elements has the smallest radius?
1994
Use principles of atomic structure and/or chemical bonding to answer each of the following.
(a) The radius of the Ca atom is 0.197 nanometer; the radius of the Ca2+ ion is 0.099 nanometer.
Account for this difference.
(c) Explain the difference between Ca and K in regard to
(i) their first ionization energies,
(ii) their second ionization energies.
(d) The first ionization energy of Mg is 738 kilojoules per mole and that of Al is 578 kilojoules
per mole. Account for this difference.
1999
Answer the following questions regarding light and its interactions with molecules, atoms, and ions.
(a) The longest wavelength of light with enough energy to break the Cl-Cl bond in Cl2(g) is 495 nm.
(i) Calculate the frequency, in s-1, of the light.
(ii) Calculate the energy, in J, of a photon of the light.
(iii) Calculate the minimum energy, in kJ mol-1, of the Cl-Cl bond.
2000
Answer the following questions about the element selenium, Se (atomic number 34).
(b) Write the complete electron configuration (e.g., 1s2 2s2. . . etc.) for a selenium atom in the ground
state. Indicate the number of unpaired electrons in the ground-state atom, and explain your reasoning.
(c) In terms of atomic structure, explain why the first ionization energy of selenium is
(i) less than that of bromine (atomic number 35), and
(ii) greater than that of tellurium (atomic number 52).
2008A
5. Using principles of atomic and molecular structure and the information in the table below, answer the
following questions about atomic fluorine, oxygen, and xenon, as well as some of their compounds.
Atom
First Ionization Energy (kJ mole-1)
F
1681.0
O
1313.9
Xe
?
a)
Write the equation for the ionization of atomic fluorine that requires 1681.0 kJ mol-1.
b)
Account for the fact that the first ionization energy of atomic fluorine is greater than that of
atomic oxygen. (You must discuss both atoms in your response.)
c)
Predict whether the first ionization energy of atomic xenon is greater than, less than, or equal to
the first ionization energy of atomic fluorine. Justify your prediction.
2009A
6. Answer the following questions related to sulfur and one of its compounds.
a.
b.
Consider the two chemical species S and S2-.
i.
Write the electron configuration (e.g., 1s22s2 …) of each species.
ii.
Explain why the radius of the S2- ion is larger than the radius of the S atom.
iii.
Which of the two species would be attracted into a magnetic field? Explain.
The S2- ion is isoelectronic with the Ar atom. From which species, S2- or Ar, is it easier to remove
an electron? Explain.
2002A
6. Use the principles of atomic structure and/or chemical bonding to explain each of the following. In each
part, you answer must include references to both substances.
a.) The atomic radius of Li is larger than that of Be.
b.) The second ionization energy of K is greater than the second ionization energy of Ca.
2003B
7. Account for the following observations using principles of atomic structure and/or chemical bonding.
In each part, your answer must include specific information about both substances.
a. The Ca2+ and Cl- ions are isoelectronic, but their radii are not the same. Which ion has the
larger radius? Explain.
b. Carbon and lead are in the same group of elements, but carbon is classified as a nonmetal and
lead is classified as a metal.
c. Compounds containing Kr have been synthesized, but there are no known compounds that
contain He.
d. The first ionization energy of Be is 900 kJ mol-1, but the first ionization energy of B is 800 kJ
mol-1.
2010A
2 Al(s) + 3 Zn2+(aq)  2 Al3+(aq) + 3 Zn(s)
6. Respond to the following statements and questions that relate to the species and the reaction
represented above.
a. Write the complete electron configuration (e.g., 1s22s2…) for Zn2+
b. Which species, Zn or Zn2+, has the greater ionization energy? Justify your answer.
2007B
2.
b.
A major line in the emission spectrum of neon corresponds to a frequency of 4.34 x 1014 s-1. Calculate the
wavelength, in nanometers, of light that corresponds to this line.
c.
In the upper atmosphere, ozone molecules decompose as they absorb ultraviolet (UV) radiation, as
shown by the equation below. Ozone serves to block harmful ultraviolet radiation that comes from the
Sun.
UV
O3(g) 
O2(g) + O(g)
A molecule of O3(g) absorbs a photon with a frequency of 1.00 x 1015 s-1.
i.
How much energy, in joules, does the O3(g) molecule absorb per photon?
ii.
The minimum energy needed to break an oxygen-oxygen bond in ozone is 387 kJ mol-1. Does a
photon with a frequency of 1.00 x 1015 s-1 have enough energy to break this bond? Support your
answer with a calculation.
2009A
3. Initiating most reactions involving chlorine gas involves breaking the Cl – Cl bond, which has a bond energy
of 242 kJ mol-1.
b.)
Calculate the amount of energy, in joules, needed to break a single Cl – Cl bond.
c.)
Calculate the longest wavelength of light, in meters, than can supply the energy per photon
necessary to break the Cl – Cl bond.
Multiple Choice
1. The photoelectron spectra (PES) above shows the energy required to remove a 1s electron from a
nitrogen atom and from an oxygen atom. Which of the following statements best accounts for the
peak in the upper spectrum being to the right of the peak in the lower spectrum?
a. Nitrogen atoms have a half-filled p subshell
b. There are more electron-electron repulsions in oxygen atoms than in nitrogen atoms
c. Electrons in the p subshell of oxygen atoms provide more shielding than electrons in the p
subshell of nitrogen atoms
d. Nitrogen atoms have a smaller nuclear charge than oxygen atoms
Element
Atomic Radius
First ionization energy
Calcium
194 pm
590 kJ/mol
Potassium
2. Based on the periodic trends and the data in the table above, which of the following are the most
probable values of the atomic radius and the first ionization energy for potassium, respectively?
a.
b.
c.
d.
242 pm, 633 kJ/mol
242 pm, 419 kJ/mol
120 pm, 633 kJ/mol
120 pm, 419 kJ/mol
3. The ionization energies for element X are listed in the table above. On the basis of the data, element X
is most likely to be
A.
B.
C.
D.
E.
Na
Mg
Al
Si
P
4. In the periodic table, as the atomic number increases from 11 to 17, what happens to the atomic
radius?
A. It remains constant.
B. It increases only.
C. It increases, then decreases.
D. It decreases only.
E. It decreases, then increases.
5. In which of the following groups are the three species isoelectronic; i.e., have the same number of
electrons?
A. S2– , K+, Ca2+
B. Sc, Ti, V2+
C. O2–, S2–, Cl–
D. Mg2+, Ca2+, Sr2+
E. Cs, Ba2+, La3+
6. The effective nuclear charge experienced by the outermost electron of Na is different than the
effective nuclear charge experienced by the outermost electron of Ne. This difference best accounts
for which of the following?
A. Na has a greater density at standard conditions than Ne.
B. Na has a lower first ionization energy than Ne.
C. Na has a higher melting point than Ne.
D. Na has a higher neutron-to-proton ratio than Ne.
E. Na has fewer naturally occurring isotopes than Ne.
7. Which of the following best helps to account for the fact that the F– ion is smaller than the O2– ion?
A. F– has a larger nuclear mass than O2– has.
B. F– has a larger nuclear charge than O2– has.
C. F– has more electrons than O2– has.
D. F– is more electronegative than O2– is.
E. F– is more polarizable than O2– is.