All isotopes of an element have the same number of protons. Isotopes are forms of an element that have different numbers of neutrons. Isotopes are named by writing the element name followed by the mass number, which is the number of protons plus neutrons. The average atomic mass shown for an element on the periodic table takes into account the relative abundance of all its isotopes.
3. Atomic Structure Graphic Organizer
+
+
Proton
Electron
Nucleus
-
-
Energy
Levels
Neutron
-
-
Helium Atom
Electron
Cloud
+ 1 (positive) 0 (no charge neutral)
- 1 (negative)
1 AMU 1 AMU
0 AMU Electrons swirl around
the nucleus at high
speeds forming a cloud.
Far from the nucleus
Number of protons
nucleus nucleus
Number
Atomic
Average
Mass
Atomic
protons + neutrons
Study
7. 10. What is the reference point?
CST Review Questions
21
8. How are electrons, protons and neutrons arranged in the atom?
A. Protons and neutrons are in the center of the atom.
Bohr Atom
protons
neutrons
9. How are electrons, protons and neutrons arranged in the atom?
Bohr Atom
protons
neutrons
nucleus
1. The center of the atom is called the nucleus.
10. How are electrons, protons and neutrons arranged in the atom?
B. Electrons swirl around the nucleus at high speeds,
forming a cloud.
Bohr Atom
electrons
Electron Cloud
11. How are electrons, protons and neutrons arranged in the atom?
protons
neutrons
nucleus
Copy This Diagram in Your Notes.
electrons
12. 10. What is the reference point?
CST Review Questions
21
13. 10. What is the reference point?
CST Review Questions
21
20. How are isotopes written?
Carbon-13
X. Isotope names contain the name of the
element and the mass number of the
isotope.
Isotope name
element mass number
21. How many neutrons do atoms have?
protons
neutrons
Carbon-14
6 protons
8 neutrons
14 total
Carbon-13
6 protons
7 neutrons
13 total
Carbon-12
6 protons
6 neutrons
12 total
IX. Forms of an element with different
numbers of neutrons are called isotopes.
3 isotopes of carbon
22. How many neutrons do atoms have?
Carbon-14
6 protons
8 neutrons
14 total
Carbon-13
6 protons
7 neutrons
13 total
Carbon-12
6 protons
6 neutrons
12 total
A. Isotopes are named by the element’s
name and mass number (the number of
protons + neutrons.)
isotopes of carbon
25. Think-Group-Share
1. THINK: Read the question and THINK
about the answer.
2. GROUP: Discuss the answer with your
teammates and agree on the correct
answer.
3. SHARE your answers by writing them on
the magnetic slate and holding them up.
28. What are the smallest particles of an element?
I. Atoms are the smallest particles of an
element (building blocks of matter).
Nickel Atoms
Nickel
Coin
Nickel Metal Foil
31. What subatomic particles are in the atom?
II. Scientists discovered that atoms contain
three subatomic particles :
- protons
- neutrons
- electrons.
An Oxygen Atom
proton
neutron
electron
The Element Oxygen
40. How are electrons, protons and neutrons arranged in the atom?
B. Electrons are in different energy levels
depending on their energy.
Bohr Atom
Electron Cloud
electrons
electron orbitals
electron shells
electrons
Electrons move in
different energy
levels
41. Think-Group-Share
How do electrons move in the
atom?
A. They do not move.
B. They move slowly in the nucleus
of the atom.
C. They swirl around the nucleus at
high speeds.
42. Think-Group-Share
How do electrons move in the
atom?
A. They do not move.
B. They move slowly in the nucleus
of the atom.
C. They swirl around the nucleus at
high speeds.
43. How are electrons, protons and neutrons arranged in the atom?
Electrons swirl around the nucleus at high
speeds
Bohr Atom
electrons
High Speeds
46. How are electrons, protons and neutrons arranged in the atom?
Electrons move so fast they form a blur called
an electron cloud.
Bohr Atom
electrons
Electron Cloud
58. What are the charges of the subatomic particles?
IV. Scientists discovered that:
- protons have a positive (+1) charge
- electrons have a negative (-1) charge
- neutrons have no (0) charge
Atom
proton: + charge
neutron: no charge
electron: - charge
59. Think-Group-Share
How do the sizes of protons and
neutrons compare?
A. They are the same size.
B. Protons are smaller than
neutrons.
C. Neutrons are smaller than
protons.
60. Think-Group-Share
How do the sizes of protons and
neutrons compare?
A. They are the same size.
B. Protons are smaller than
neutrons.
C. Neutrons are smaller than
protons.
61. What are the masses of electrons, protons and neutrons?
V. Protons and neutrons are the same size
and mass.
protons
neutrons
62. Think-Group-Share
How do the sizes of protons and
electrons compare?
A. They are the same size.
B. Electrons are MUCH smaller than
protons.
C. Protons are MUCH smaller than
electrons.
63. Think-Group-Share
How do the sizes of protons and
electrons compare?
A. They are the same size.
B. Electrons are MUCH smaller than
protons.
C. Protons are MUCH smaller than
electrons.
64. What are the masses of electrons, protons and neutrons?
C. Electrons are MUCH smaller than protons
and neutrons.
protons
neutrons
electrons
65. What are the masses of electrons, protons and neutrons?
1. Electrons are almost 2000 times lighter than
protons and neutrons.
protons
neutrons
electrons
2000 2000
71. What are the masses of electrons, protons and neutrons?
2. Electrons are so small that their mass is
almost nothing (0 AMU).
protons
neutrons
electrons
0 AMU
74. What are the masses of electrons, protons and neutrons?
B. The mass of a neutron is 1 AMU (atomic
mass unit).
neutron:
1 AMU
1 AMU
75. Think-Group-Share
What is atomic number?
A. The number of protons + neutrons.
B. The number of protons.
C. The number of neutrons.
76. Think-Group-Share
What is atomic number?
A. The number of protons + neutrons.
B. The number of protons.
C. The number of neutrons.
77. How many protons do atoms have?
B. The number of protons of an
element is called the atomic number.
Carbon
Oxygen
6 protons
Atomic Number = 6
8 protons
Atomic Number = 8
Hydrogen
1 proton
Atomic Number = 1
78. Think-Group-Share
What is the arrow in the diagram
pointing to?
C
6
Carbon
12.01
Average Atomic
Mass
Atomic Number
Mass Number
79. Think-Group-Share
What is the arrow in the diagram
pointing to?
Atomic Mass
Atomic Number
Mass Number of
the most common
isotope.
C
6
Carbon
12.01
89. Think-Group-Share
What is mass number?
A. The number of protons + neutrons.
B. The number of protons.
C. The number of neutrons.
90. Think-Group-Share
What is mass number?
A. The number of protons + neutrons.
B. The number of protons.
C. The number of neutrons.
91. How many neutrons do atoms have?
A. The sum of neutrons + protons in an
element is called the mass number.
protons
neutrons
Carbon-14
6 protons
8 neutrons
14 total
(Mass Number)
Carbon-13
6 protons
7 neutrons
13 total
(Mass Number)
Carbon-12
6 protons
6 neutrons
12 total
(Mass Number)
92. How are isotopes written?
Carbon-13
III. Isotope names contain the name of the
element and the mass number of the
isotope.
Isotope name
element mass number
Draw this
95. Think-Group-Share
What is average atomic mass?
A. The number of protons + neutrons.
B. The number of neutrons.
C. The average mass of all of the
isotopes.
96. Think-Group-Share
What is average atomic mass?
A. The number of protons + neutrons.
B. The number of neutrons.
C. The average mass of all of the
isotopes.
97. How are mass numbers shown on the periodic table?
A. The average atomic mass is the average
mass of all of the isotopes of that element.
C
6
Carbon
12.01 Average Atomic Mass
(larger number on the chart)
Atomic Number
(smaller number on the chart)
protons
98. Think-Group-Share
What is the arrow in the diagram
pointing to?
C
6
Carbon
12.01
Average Atomic
Mass
Atomic Number
Mass Number
99. Think-Group-Share
What is the arrow in the diagram
pointing to?
C
6
Carbon
12.01
Average Atomic
Mass
Atomic Number
Mass Number of
the most common
isotope.
100. How are mass numbers shown on the periodic table?
IV. The average atomic mass of an element
is shown on the periodic square (larger
number).
C
6
Carbon
12.01 Average Atomic Mass
(larger number on the chart)
Atomic Number
(smaller number on the chart)
protons
101. Think-Group-Share
What is the same about all isotopes
of an element?
A. They have the same number of
neutrons.
B. They have the same number of
protons.
C. They have the same atomic mass.
102. Think-Group-Share
What is the same about all isotopes
of an element?
A. They have the same number of
neutrons.
B. They have the same number of
protons.
C. They have the same atomic mass.
103. How many neutrons do atoms have?
I. An element can have different
numbers of neutrons.
protons
neutrons
Carbon-14
6 protons
8 neutrons
14 total
Carbon-13
6 protons
7 neutrons
13 total
Carbon-12
6 protons
6 neutrons
12 total
104. Think-Group-Share
What is different about the isotopes
of an element?
A. They have different numbers of
neutrons.
B. They have different numbers of
electrons.
C. They have different numbers of
protons.
105. Think-Group-Share
What is different about the isotopes
of an element?
A. They have different numbers of
neutrons.
B. They have different numbers of
electrons.
C. They have different numbers of
protons.
106. What is an isotope of an element?
protons
neutrons
Carbon-14
6 protons
8 neutrons
14 total
Carbon-13
6 protons
7 neutrons
13 total
Carbon-12
6 protons
6 neutrons
12 total
II. The same element with different
numbers of neutrons is called an isotope.
3 isotopes of carbon
110. Think-Group-Share
What is the isotope name of the atom
with 3 protons and 4 neutrons?
Lithium-7
Mass Number = 3 protons + 4 neutrons
111. How are isotopes written?
Carbon-13
Review
Isotope name
element mass number
112. How are isotopes written?
C-13
Review
Isotope Symbol
chemical
symbol
mass number
113. Where are the most common mass numbers shown?
Review
C
6
Carbon
12.01 Avg Atomic Mass
(larger number on the chart)
Atomic Number
(smaller number on the chart)
protons
114. Where are the most common mass numbers shown?
Review
C
6
Carbon
12.01 Atomic Mass
(larger number on the chart)
Atomic Number
(smaller number on the chart)
protons