atomic mass and isotopes
Name:
1.
Date:
Which two particles have approximately the same mass?
A.
neutron and electron
B.
neutron an deutron
C.
proton and neutron
D. proton and electron
2.
The mass number of an atom is equal to the number of
A.
neutrons, only
B.
protons, only
C.
neutrons plus protons
D. electrons plus protons
3.
An atom of
226
Rn
88
contains
A.
88 protons and 138 neutrons
B.
88 protons and 138 electrons
C.
88 electrons and 226 neutrons
D. 88 electrons and 226 protons
page 1
4.
If the nucleus of an atom is represented as
A.
Na
B.
Al
C.
Mg
24 X,
11
the atom is
D. Br
5.
Which of the following particles has the least mass?
A.
alpha particle
B.
beta particle
C.
proton
D. neutron
6.
The nucleus is the part of the atom that
A.
consist mostly of empty space
B.
has a negative charge
C.
occupies most of the atom's total volume
D. contains most of the atom's total mass
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atomic mass and isotopes
7.
The total number of protons and neutrons in the nuclide
A.
54
B.
37
C.
20
37
Cl
17
is
D. 17
8.
Experimental evidence indicates that the nucleus of an atom
A.
contains most of the mass of the atom
B.
contains a small percentage of the mass of the atom
C.
has no charge
D. has a negative charge
9.
What is the mass number of an atom which contains 21 electrons, 21 protons, and 24 neutrons?
A.
21
B.
42
C.
45
D. 66
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atomic mass and isotopes
10.
What is the mass number of an ion that has 83 protons, 80 electrons, and 126 neutrons?
A.
83
B.
206
C.
209
D. 289
11.
The nucleus of an atom of
127 I
53
contains
A.
53 neutrons and 127 protons
B.
53 protons and 127 neutrons
C.
53 protons and 74 neutrons
D. 53 protons and 74 electrons
12.
What is the mass number of an atom which contains 28 protons, 28 electrons, and 34 neutrons?
A.
28
B.
56
C.
62
D. 90
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atomic mass and isotopes
13.
The mass number of an atom is always equal to the total number of its
A.
electrons, only
B.
protons, only
C.
electrons plus protons
D. protons plus neutrons
14.
What is the mass number of an atom that contains 19 protons, 19 electrons, and 20 neutrons?
A.
19
B.
20
C.
39
D. 58
15.
The atomic mass of an element is de ned as the weighted average mass of that element's
A.
most abundant isotope
B.
least abundant isotope
C.
naturally occurring isotopes
D. radioactive isotopes
page 5
atomic mass and isotopes
16.
An atom of uorine has a mass of 19 atomic mass units. The total number of protons and neutrons in its nucleus is
A.
9
B.
10
C.
19
D. 28
17.
In which list are the elements arranged in order of increasing atomic mass?
A.
Cl, K, Ar
B.
Fe, Co, Ni
C.
Te, I, Xe
D. Ne, F, Na
18.
An atom of carbon-12 and an atom of carbon-14 di er in
A.
atomic number
B.
mass number
C.
nuclear charge
D. number of electrons
page 6
atomic mass and isotopes
19.
The atomic mass of an element is calculated using the
A.
atomic number and the ratios of its naturally occurring isotopes
B.
atomic number and the half-lives of each of its isotopes
C.
masses and the ratios of its naturally occurring isotopes
D. masses and the half-lives of each of its isotopes
20.
Base your answer(s) to the following question(s) on the data table below, which shows three isotopes of neon.
Isotope
20Ne
21Ne
22Ne
Atomic Mass
(atomic mass units)
Percent Natural
Abundance
20.99
0.3%
19.99
21.99
90.9%
8.8%
In terms of atomic particles, state one di erence between these three isotopes of neon.
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atomic mass and isotopes
21.
Which diagram represents the nucleus of an atom of
27 Al ?
13
A.
B.
C.
D.
22.
Compared to an atom of phosphorus-31, an atom of sulfur-32 contains
A.
one less neutron
B.
one less proton
C.
one more neutron
D. one more proton
page 8
atomic mass and isotopes
23.
What is the mass number of an atom that has six protons, six electrons, and eight neutrons?
A.
6
B.
12
C.
14
D. 20
24.
25.
Which isotopic notation identi es a metalloid that is matched with the corresponding number of protons in each of
its atoms?
A.
24 Mg
B.
28 Si
C.
75 As
and 75 protons
D.
80 Br
and 80 protons
and 12 protons
and 14 protons
What is the mass number of an alpha particle?
A.
1
B.
2
C.
0
D. 4
page 9
atomic mass and isotopes
26.
Base your answer(s) to the following question(s) on the information below.
Atomic Diagrams of Magnesium and Aluminum
Key
= electron
Element
magnesium
Lewis Electron-Dot
Diagram
Electron-Shell
Diagram
aluminum
Determine the mass number of the magnesium atom represented by the electron-shell diagram.
27.
Base your answer(s) to the following question(s) on the information below.
Naturally Occurring Isotopes of Copper
Isotope
Notation
Percent Natural
Abundance (%)
Atomic Mass
(atomic mass units, u)
Cu-65
30.83
64.928
Cu-63
69.17
62.930
In the space below, show a correct numerical setup for calculating the atomic mass of copper.
page 10
atomic mass and isotopes
28.
29.
The most common isotope of chromium has a mass number of 52. Which notation represents a di erent isotope of
chromium?
A.
52
Cr
24
B.
54
Cr
24
C.
24 Cr
52
D.
24 Cr
54
The notation for the nuclide
137
Cs
55
gives information about
A.
mass number, only
B.
atomic number, only
C.
both mass number and atomic number
D. neither mass number nor atomic number
30.
Which particles have approximately the same mass?
A.
alpha particle and beta particle
B.
alpha particle and proton
C.
neutron and positron
D. neutron and proton
page 11
atomic mass and isotopes
31.
Which phrase describes an atom?
A.
a negatively charged nucleus surrounded by positively charged protons
B.
a negatively charged nucleus surrounded by positively charged electrons
C.
a positively charged nucleus surrounded by negatively charged protons
D. a positively charged nucleus surrounded by negatively charged electrons
32.
The atomic mass of magnesium is the weighted average of the atomic masses of
A.
all of the arti cially produced isotopes of Mg
B.
all of the naturally occurring isotopes of Mg
C.
the two most abundant arti cially produced isotopes of Mg
D. the two most abundant naturally occurring isotopes of Mg
page 12
atomic mass and isotopes
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atomic mass and isotopes
01/22/2016
20.
Answer:
1.
Answer:
C
2.
Answer:
C
3.
Answer:
A
21.
Answer:
B
4.
Answer:
A
22.
Answer:
D
5.
Answer:
B
23.
Answer:
C
6.
Answer:
D
24.
Answer:
B
7.
Answer:
B
25.
Answer:
D
8.
Answer:
A
26.
Answer:
23
9.
Answer:
C
27.
Answer:
10.
Answer:
C
11.
Answer:
C
28.
Answer:
B
12.
Answer:
C
29.
Answer:
C
13.
Answer:
D
30.
Answer:
D
14.
Answer:
C
31.
Answer:
D
15.
Answer:
C
32.
Answer:
B
16.
Answer:
C
17.
Answer:
A
18.
Answer:
B
19.
Answer:
C
Each isotope has a di erent number of
neutrons or di erent number of neutrons
or Ne-22 has two more neutrons than
Ne-20 and one more neutron than Ne-21.
(0:6917)(62:930u) + (0:3083)(64:928u)
(69:17)(62:930) + (30:83)(64:928)
100