Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
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1.
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If E
is the symbol for an element, which two of the following symbols represent isotopes of the same
element?
a. | 1 and
2 | c. | 1 and
4 | b. | 3 and
4 | d. | 2 and
3 | | | | |
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2.
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Select the correct symbol for an atom of tritium.
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3.
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Which
of the following sets of symbols represents isotopes of the same element?
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4.
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How
is the number of neutrons in the nucleus of an atom calculated? a. | Add the number
of electrons and protons together. | b. | Subtract the number of electrons from the number of
protons. | c. | Subtract the number of protons from the mass
number. | d. | Add the mass number to the number of
electrons. | | |
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5.
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In
which of the following is the number of neutrons correctly represented? a. |  F has 0 neutrons. | c. |  Mg has 24 neutrons. | b. |  As has 108
neutrons. | d. |  U has 146 neutrons. | | | | |
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6.
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How
do the isotopes hydrogen-1 and hydrogen-2 differ? a. | Hydrogen-2 has one more electron than
hydrogen-1. | b. | Hydrogen-2 has one neutron; hydrogen-1 has
none. | c. | Hydrogen-2 has two protons; hydrogen-1 has
one. | d. | Hydrogen-2 has
one proton; hydrogen-1 has none. | | |
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7.
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Which
of the following isotopes has the same number of neutrons as phosphorus-31?
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8.
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The
atomic mass of an element is the ____. a. | total number of subatomic particles in its
nucleus | b. | weighted average of the masses of the isotopes of the
element | c. | total mass of the isotopes of the
element | d. | average of the mass number and the atomic number for the
element | | |
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9.
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The
atomic mass of an element depends upon the ____. a. | mass of each electron in that element | b. | mass of each
isotope of that element | c. | relative abundance of protons in that
element | d. | mass and relative abundance of each isotope of that
element | | |
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10.
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Which
of the following is necessary to calculate the atomic mass of an element? a. | the atomic mass
of carbon-12 | b. | the atomic number of the element | c. | the relative
masses of the element’s protons and neutrons | d. | the masses of
each isotope of the element | | |
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Short Answer
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11.
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List
the number of protons, neutrons, and electrons in  C.
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12.
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Chlorine has two naturally occurring isotopes, Cl-35 and Cl-37. The atomic mass of
chlorine is 35.45. Which of these two isotopes of chlorine is more abundant?
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13.
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Consider an element Z that has two naturally occurring isotopes with the following
percent abundances: the isotope with a mass number of 19.0 is 55.0% abundant; the isotope with a mass
number of 21.0 is 45.0% abundant. What is the average atomic mass for element Z?
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14.
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A
fictitious element X is composed of 10.0 percent of the isotope  ,
20.0 percent of the isotope  , and 70.0
percent of the isotope  . Estimate the atomic mass of
element X.
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15.
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The
element chromium has four naturally occurring isotopes. Use the relative abundance of each to
calculate the average atomic mass of chromium.
 Cr = 4.34%,
 Cr = 83.79%,  Cr = 9.50%,  Cr =
2.37%.
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