AP CHEMISTRY Scoring Guide
1.6 Photoelectron Spectroscopy Quiz
1.
The photoelectron spectra above show 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.
Electrons in the p subshell of oxygen atoms provide more shielding than electrons in the p subshell of
(C)
nitrogen atoms.
(D) Nitrogen atoms have a smaller nuclear charge than oxygen atoms.
The complete photoelectron spectrum of a pure element is shown in the diagram above.
2. According to the complete photoelectron spectrum, which of the following is the identity of the element?
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Scoring Guide
1.6 Photoelectron Spectroscopy Quiz
(A) Be
(B) C
(C) O
(D) Ne
Answer D
Correct. Peak corresponds to the most tightly bound electrons, which are in the innermost shell (the
two electrons). Peak corresponds to the next most tightly bound electrons, the two electrons.
Peak corresponds to the next most tightly bound electrons, the electrons. There are three times as
many electrons associated with peak than with either peak or ; thus, the configuration must be
, which is the configuration of .
3. If peaks and represent sublevels, which of the following sublevels is represented by peak ?
(A)
(B)
(C)
(D)
Answer B
Correct. The list of sublevels in order of increasing energy is . Peak corresponds to the
electrons, peak corresponds to the electrons, and peak corresponds to the electrons.
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Scoring Guide
1.6 Photoelectron Spectroscopy Quiz
4. For parts of the free response question that require calculations, clearly show the method used and the steps
involved in arriving at your answers. You must show your work to receive credit for your answer. Examples and
equations may be included in your answers where appropriate.
The photoelectron spectrum for an unknown element is shown above.
(a) Based on the photoelectron spectrum, identify the unknown element and write its electron configuration.
(b) Consider the element in the periodic table that is directly to the right of the element identified in part (a).
Would the peak of this element appear to the left of, the right of, or in the same position as the peak of the
element in part (a)? Explain your reasoning.
Part (a)
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0 1 2
The response includes both of the following criteria:
The element is phosphorus, .
The electron configuration of is .
Part (b)
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Scoring Guide
1.6 Photoelectron Spectroscopy Quiz
0 1 2
The response meets both of the criteria below:
The response indicates that the peak would be to the left of the peak in the spectrum shown.
The response indicates that the electron is in a lower energy state (and thus has a larger binding
energy) because the nucleus of the element that is directly to the right in the periodic table would have
more protons (16) than the number of protons (15) in the element corresponding to the given spectrum.
5.
The photoelectron spectra for and are represented above. Which of the following statements best accounts
for the fact that the peak on the spectrum is farther to the left and higher than the peak on the spectrum?
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Scoring Guide
1.6 Photoelectron Spectroscopy Quiz
(A) has an additional valence electron in a higher energy level than the valence electron in .
(B) has a greater nuclear charge than and an additional electron in the same energy level.
has a completely filled valence shell in which the electrons are a greater distance from the nucleus
(C)
than the distance between the nucleus and its electron.
(D) It takes longer for the electrons in to be removed due to the higher nuclear mass of .
Answer B
Correct. The nucleus has two protons. The greater nuclear charge of increases the attraction of its
two electrons to the nucleus, increasing their binding energy, which moves the peak to the left. The peak
is twice the height of the peak for because there are twice as many electrons in the orbital of the He
atom than in the orbital of the atom.
6.
The complete photoelectron spectrum of an element is given above. Which of the following electron configurations
is consistent with the spectrum?
(A)
(B)
(C)
(D)
Answer B
Correct. The leftmost peak in the spectrum has the highest energy and contains two electrons; this is the
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Scoring Guide
1.6 Photoelectron Spectroscopy Quiz
peak that corresponds to the electrons. Moving to the right, the next peak is the peak, then the
peak, and then the peak. The last peak is the peak, which contains only 3 electrons. The correct
electron configuration .
7.
The photoelectron spectra of the 1s electrons of two isoelectronic species, Ca2+ and Ar, are shown above. Which of
the following correctly identifies the species associated with peak X and provides a valid justification?
(A) Ar, because it has completely filled energy levels
(B) Ar, because its radius is smaller than the radius of Ca2+
(C) Ca2+, because its nuclear mass is greater than that of Ar
(D) Ca2+, because its nucleus has two more protons than the nucleus of Ar has
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Scoring Guide
1.6 Photoelectron Spectroscopy Quiz
8.
A sample containing atoms of C and F was analyzed using x-ray photoelectron spectroscopy. The portion of the
spectrum showing the 1s peaks for atoms of the two elements is shown above. Which of the following correctly
identifies the 1s peak for the F atoms and provides an appropriate explanation?
(A) Peak X, because F has a smaller first ionization energy than C has.
(B) Peak X, because F has a greater nuclear charge than C has.
(C) Peak Y, because F is more electronegative than C is.
(D) Peak Y, because F has a smaller atomic radius than C has.
9.
The complete photoelectron spectrum for an element is shown above. Which of the following observations would
provide evidence that the spectrum is consistent with the atomic model of the element?
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1.6 Photoelectron Spectroscopy Quiz
(A) A neutral atom of the element contains exactly two electrons.
(B) The element does not react with other elements to form compounds.
(C) In its compounds, the element tends to form ions with a charge of .
(D) In its compounds, the element tends to form ions with a charge of .
Answer C
Correct. The photoelectron spectrum indicates that the element has one valence electron, which means
that element tends to form ions with a charge.
10.
The complete photoelectron spectrum of a pure element is represented above. Which of the following correctly
identifies both the element and the atomic orbitals represented by peak X and peak Y?
Element Peak X Peak Y
A
B
C
D
(A) A
(B) B
(C) C
(D) D
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Scoring Guide
1.6 Photoelectron Spectroscopy Quiz
Answer C
Correct. The electron configuration of is . This is the unknown element because both of its
peaks have the same height, representing equal numbers of electrons in its two orbitals. The peak with
the higher binding energy, peak X, corresponds to the electrons because the electrons are closer to
the nucleus and more tightly held.
11.
The photoelectron spectrum for the element nitrogen is represented above. Which of the following best explains
how the spectrum is consistent with the electron shell model of the atom?
(A) The leftmost peak represents the valence electrons.
(B) The two peaks at the right represent a total of three electrons.
(C) The electrons in the sublevel have the smallest binding energy.
(D) The electrons in the sublevel have the smallest binding energy.
Answer D
Correct. The electrons in the sublevel have the smallest binding energy because these electrons have
the weakest attraction to the nucleus and are more easily removed from the atom.
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Scoring Guide
1.6 Photoelectron Spectroscopy Quiz
12.
The complete photoelectron spectra of neutral atoms of two unknown elements, X and Y, are shown above. Which
of the following can be inferred from the data?
(A) Element X has a greater electronegativity than element Y does.
(B) Element X has a greater ionization energy than element Y does.
(C) Element Y has a greater nuclear charge than element X does.
(D) The isotopes of element Y are approximately equal in abundance, but those of element X are not.
13. For parts of the free-response question that require calculations, clearly show the method used and the steps
involved in arriving at your answers. You must show your work to receive credit for your answer. Examples and
equations may be included in your answers where appropriate.
The complete photoelectron spectrum of an unknown element is given above.
(a) Draw an above the peak that corresponds to the orbital with electrons that are, on average, closest to the
nucleus. Justify your answer in terms of Coulomb’s law.
(b) Based on the spectrum, write the complete electron configuration of the element.
(c) On the graph, draw the peak(s) corresponding to the valence electrons of the element that has one more proton
in its nucleus than the unknown element has.
Part A
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1.6 Photoelectron Spectroscopy Quiz
0 1
The response includes both of the following criteria.
The response shows
The response includes a justification that indicates that the electrons closest to the nucleus have the
greatest binding energy because the attraction between the charges (electron and nucleus) is greatest
when the distance between them ( r ) is the least.
Part B
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0 1
The response includes the electron configuration .
Part C
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0 1 2
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Scoring Guide
1.6 Photoelectron Spectroscopy Quiz
The response meets both of the following two criteria.
A peak is drawn at the same location as that of the dashed-line peak shown below.
A peak is drawn with the same height as that of the dashed-line peak shown below.
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