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Name:
1. Base your answer to the following question on the information below.
Two isotopes of potassium are K-37 and K-42.
What is the total number of neutrons in the nucleus of a K-37 atom?
2. Base your answer to the following question on the table below.
On the same grid, plot the data from the table. Circle and connect the points.
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3. Base your answer to the following question on
the information and diagram below.
One model of the atom states that atoms are
tiny particles composed of a uniform mixture of
positive and negative charges. Scientists
conducted an experiment where alpha particles
were aimed at a thin layer of gold atoms.
Most of the alpha particles passed directly
through the gold atoms. A few alpha particles
were deflected from their straight-line paths. An
illustration of the experiment is shown below.
A few of the alpha particles were deflected.
What does this evidence suggest about the
structure of the gold atoms?
4. Base your answer to the following question on
the information below.
The accepted values for the atomic
mass and percent natural abundance of
each naturally occurring isotope of
silicon are given in the data table below.
Determine the total number of neutrons in an
atom of Si-29.
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5. Naturally occurring boron is composed of two isotopes. The percent abundance and the mass of each isotope are
listed below.
• 19.9% of the boron atoms have a mass of 10.013 atomic mass units.
• 80.1% of the boron atoms have a mass of 11.009 atomic mass units.
Calculate the atomic mass of boron. Your response must include both a correct numerical setup and the
calculated result.
__________________ atomic mass units
6. What is the total number of neutrons in an atom
of aluminum-27?
7. Describe the electrons in an atom of carbon in the ground state. Your response must include:
• the charge of an electron
• the location of electrons based on the wave-mechanical model
• the total number of electrons in a carbon atom
8. 40% of the isotopes of an element have a mass
of 16 amu. 60% of the isotopes have a mass of
18 amu. Calculate the average atomic mass.
Show all work.
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9. The table below shows the electronegativity of selected elements of the Periodic Table.
a On the grid set up a scale for electronegativity on the y-axis. Plot the data by drawing a best-fit line.
b Using the graph, predict the electronegativity of nitrogen. _________________
c For these elements, state the trend in electronegativity in terms of atomic number.
10. Base your answer to the following question on the information below.
State, in terms of the number of subatomic particles, one similarity and one difference between the atoms of
these isotopes of sulfur.
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11. Base your answer to the following question on the data table provided.
Record the electronegativity for the elements with atomic numbers 11 through 17.
12. Base your answer to the following question on
the information below.
Elements with atomic numbers 112 and
114 have been produced and their
IUPAC names are pending approval.
However, an element that would be put
between these two elements on the
Periodic Table has not yet been
produced. If produced, this element will
be identified by the symbol Uut until an
IUPAC name is approved.
Identify one element that would be chemically
similar to Uut.
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13. Base your answer to the following question on the information below.
Arsenic is often obtained by heating the ore arsenopyrite, FeAsS. The decomposition of FeAsS is
represented by the balanced equation below.
In the solid phase, arsenic occurs in two forms. One form, yellow arsenic, has a density of 1.97 g/cm3 at
STP. The other form, gray arsenic, has a density of 5.78 g/cm3 at STP. When arsenic is heated rapidly in air,
arsenic(III) oxide is formed.
Although arsenic is toxic, it is needed by the human body in very small amounts. The body of a healthy
human adult contains approximately 5 milligrams of arsenic.
Convert the mass of arsenic found in the body of a healthy human adult to grams.
14. A knowledge of the ionization energies of elements can be very useful in predicting the activity and type of
reaction an element will have.
a What does the ionization energy quantitatively measure about an atom?
b Why do ionization energies decrease from the top to the bottom of a group on the periodic table of elements?
c Why do ionization energies increase from left to right across any period?
15. Base your answer to the following question on
the information below.
A metal, M, was obtained from a
compound in a rock sample.
Experiments have determined that the
element is a member of Group 2 on the
Periodic Table of the Elements.
Explain, in terms of electrons, why element M is
a good conductor of electricity.
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16. Base your answer to the following question on the Reference Tables for Physical Setting/Chemistry.
a Complete the data table provided for the following Group 18 elements: He, Ne, Ar, Kr, Xe
b Using information from your data table in part a, construct a line graph on the grid provided, following the
directions below.
• Mark an appropriate scale on the axis labeled “First Ionization Energy (kJ/mol). ”
• Plot the data from your data table. Circle each point and connect the points.
c Based on your graph in part c, describe the trend in first ionization energy of Group 18 elements as the atomic
number increases.
17. A student determines the density of zinc to be
7.56 grams per milliliter. If the accepted density
is 7.14 grams per milliliter, what is the student’s
percent error?
• Show a correct numerical setup.
• Record your answer.
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18. Base your answer to the following question on the information below.
A hydrate is a compound that has water molecules within its crystal structure. The formula for the
hydrate CuSO4•5H2O(s) shows that there are five moles of water for every one mole of CuSO4(s). When
CuSO4•5H2O(s) is heated, the water within the crystals is released, as represented by the balanced
equation below.
CuSO4•5H2O(s) —> CuSO4(s) + 5H2O(g)
A student first masses an empty crucible (a heat-resistant container). The student then masses the crucible
containing a sample of CuSO4•5H2O(s). The student repeatedly heats and masses the crucible and its
contents until the mass is constant. The student’s recorded experimental data and calculations are shown
below.
Use the student’s data to show a correct numerical setup for calculating the percent composition by mass of
water in the hydrate.
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19. Base your answer to the following question on the information below.
Archimedes (287–212 BC), a Greek inventor and mathematician, made several discoveries
important to science today. According to legend, Hiero, the king of Syracuse, commanded
Archimedes to find out if the royal crown was made of gold, only. The king suspected that the
crown consisted of a mixture of gold, tin and copper.
Archimedes measured the mass of the crown and the total amount of water displaced by the
crown when it was completely submerged. He repeated the procedure using individual samples,
one of gold, one of tin, and one of copper. Archimedes was able to determine that the crown
was not made entirely of gold without damaging it.
Determine the volume of a 75-gram sample of gold at STP.
20. Using a triple beam balance and a graduated cylinder, a student collected data on a sample of an element:
Mass of sample –
Volume of water –
Volume of water and sample –
10.9 g
30.0 ml
34.0 ml
a) Calculate the density of the sample. Show all work and use significant figures and units.
b) Based on Reference Table S, what element might the sample be?
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Answer Key
[New Exam]
1. 18.
probable location. • a
carbon atom has six
electrons.
2.
8. 17.2 amu
9.
Allow credit for plotting
all the points correctly
(±0.3 grid space). Plotted
points do not need to be
circled or connected.
3. Examples:
– Alpha particles were
deflected by the positively
charged nucleus.
– nucleus — charged
4. 15
13. 5 x 10-3 g or 0.005 g
18.
14. a) The ionization
energy is the amount of
energy needed to remove
the most loosely bound
19. 3.9 cm3
electron from an atom.
b) The electrons are
20. a) 2.7 g/ml b) Al
farther away in the lower
periods so there is less
pull from the nucleus.
Also, there is shielding
from the electrons that are
closer to the nucleus. c)
Electrons are held tighter
to an atom because of the
increase in nuclear charge.
15. Examples: – Metals
have freely moving
valence electrons. –
mobile valence electrons
– sea of mobile electrons
b The electonegativity of – Electrons are
nitrogen is 3.0 ()0.2).
delocalized.
c Example: -Atomic
number
16.
increases—electronegativit
y increases.
5. • Correct Numerical Setup
Examples:
10. Similarity: All atoms of
–– (10.013)(0.199) +
these isotopes have the
(11.009)(0.801)
same number of protons;
+ (80.1)(11.009)
–– (19.9)(10.013)
Every sulfur atom has 16
100
100
–– (10.013)(19.9%) +
protons; Difference: An S(11.009)(80.1%)
32 atom has 16 neutrons,
• Calculated Result
an S-33 atom has 17
Examples: ––10.8 atomic neutrons, an s-34 atom
mass units; ––10.81
has 18 neutrons, and an satomic mass units;
36 atom has 20 neutrons.
––10.8108 atomic mass
units
11.
6. 14
7. Answer: • an electron has a
– 7.14
17. 7.58
7.147.14
negative charge. •
Examples: 5.88 or 5.9
electrons are located in
or 6
orbitals or regions of most12. Examples: – Ti – boron