Download 3-10 What are isotopes?

Name
Class
Date
3-10 What are isotopes?
Lesson Review
Write true if the statement is true. If the statement is false, change the underlined
term to make the statement true. Write your answers in the spaces provided.
____________________ 1. All atoms of the same element have the same atomic mass.
____________________ 2. Two important isotopes of uranium are U-235 and U-200.
____________________ 3. Atoms of the same element that have different atomic masses are called
isotopes.
____________________ 4. Three isotopes of nitrogen are protium, deuterium, and tritium.
____________________ 5. The periodic table gives the average of the atomic masses of all the isotopes
of an element.
____________________ 6. The atomic number of an element never changes.
____________________ 7. An atom of hydrogen-2 has two neutrons.
____________________ 8. On the periodic table, an element’s atomic mass is not a whole number.
____________________ 9. Isotopes of an atom of an element have the same number of neutrons.
____________________ 10. All elements have two or more isotopes.
Skill Challenge
Skills: inferring, comparing
Complete the table below with the number of each kind of atomic particle found
in the isotopes.
Isotope
Protons
Neutrons
Electrons
Hydrogen-1
1.
2.
3.
Hydrogen-2
4.
5.
6.
Hydrogen-3
7.
8.
9.
Concepts and Challenges in Physical Science, Teacher’s Resources CD-ROM
(c) by Pearson Education, Inc./Globe Fearon/Pearson Learning Group. All rights reserved.
Elements and Atoms: CHAPTER 3, page 14
Name
Class
Date
Isotopes
Enrichment Activity for Lesson 3-10
Skills: interpreting a table, applying
The table below lists isotopes of hydrogen, carbon, and oxygen. Refer to the
table to answer the questions that follow.
ISOTOPES OF HYDROGEN, CARBON, AND OXYGEN
Element/Isotope
Percentage in
Nature
Atomic Mass
(amu)
Atomic Number
Mass Number
Hydrogen-1
99.9985
1.007825
1
1
Hydrogen-2
0.0015
2.001410
1
2
Hydrogen-3
Trace
?
1
3
Carbon-12
98.89
12.00000
6
12
Carbon-13
1.11
13.003
6
13
Carbon-14
Trace
?
6
14
Oxygen-16
99.759
15.995
8
16
Oxygen-17
0.037
16.999
8
17
Oxygen-18
0.204
17.999
8
18
1. How many isotopes does hydrogen have? ____________________________________________________
2. How many isotopes do carbon and oxygen have? _____________________________________________
3. Which isotopes of the three elements are the most abundant in nature? __________________________
__________________________________________________________________________________________
4. For which isotopes have scientists not been able to determine the atomic mass? Can you think of a
reason for this? ____________________________________________________________________________
__________________________________________________________________________________________
5. According to the table, how are isotopes named? ______________________________________________
6. What is true about the atomic numbers for all the isotopes of carbon? For all the isotopes of
hydrogen and oxygen? _____________________________________________________________________
7. One of these isotopes has been used by scientists as a standard for the atomic mass unit (amu). Can
you guess which one? Why? ________________________________________________________________
8. Suppose you tested a sample of oxygen to determine its atomic mass. If the mass came out to be
16.112, would you conclude that the sample consisted of only one isotope? Why or why not?
__________________________________________________________________________________________
__________________________________________________________________________________________
Concepts and Challenges in Physical Science, Teacher’s Resources CD-ROM
(c) by Pearson Education, Inc./Globe Fearon/Pearson Learning Group. All rights reserved.
Elements and Atoms: CHAPTER 3, page 15