1. Which equation represents the radioactive decay

of 22688 Ra?

1) 22688 Ra - 22286 Rn +

42He

2) 22688 Ra - 22689 Ac +

01e

3) 22688 Ra - 22687 Fr +

0+1e

4) 22688 Ra - 22588 Ra +

10n

2. The chart below shows the spontaneous nuclear

decay of U-238 to Th-234 to Pa-234 to U-234.

What is the correct order of nuclear decay

modes for the change from U-238 to U-234?

1) decay, decay, decay2) decay, decay, decay3) decay, decay, decay4) decay, decay, decay

3. Which product of nuclear decay has mass but no

charge?

1) alpha particles 3) gamma rays

2) neutrons 4) beta positrons

4. In the equation:

23940 Th

234 91 Pa + X

The symbol X represents

1) 0+1e

2) 01e

3) 10n

4) 11H

5. In the equation:

23491 Pa

234 92U + X

The X represents a

1) helium nucleus 3) proton

2) beta particle 4) neutron

6. According to the equation:

X 20882 Pb +

42He

The nucleus correctly represented by X is

1) 20480 Hg

2) 21284 Po

3) 20480 Bi

4) 21284 Pb

7. In the equation:

23490 Th

23491 Pa + X

Which particle is represented by X?

1) 01e

2) 42He

3) 11H

4) 0+1e

8. In the equation:

226 88Ra

222 86Rn + X

X represents

1) a neutron 3) a beta particle

2) a proton 4) an alpha particle

9. Given the reaction:

23491 Pa X +

01e

When the equation is correctly balanced the

nucleus represented by X is

1) 23492 U

2) 23592 U

3) 23090 Th

4) 23290 Th

10. Given the equation:

18 9F

18 8O + X

Which symbol, when substituted for X, correctly

balances the equation?

1) 11H

2) 10n

3) 01e

4) 0+1e

11. In the equation:

X 226 88Ra +

42He

The symbol X represents

1) 222 86Th

2) 230 90Th

3) 222 86Rn

4) 230 90Rn

12. A neutron has approximately the same mass as

1) an alpha particle 3) an electron

2) a beta particle 4) a proton

13. What is the half-life of sodium-25 if 1.00 gram

of a 16.00-gram sample of sodium-25 remains

unchanged after 237 seconds?

1) 47.4 s 3) 79.0 s

2) 59.3 s 4) 118 s

14. Based on Reference Table N, what is the

fraction of a sample of potassium-42 that will

remain unchanged after 62.0 hours?

15. What is the half-life and decay mode of Rn-222?

1) 1.91 days and alpha decay

2) 1.91 days and beta decay

3) 3.82 days and alpha decay

4) 3.82 days and beta decay

16. Based on Reference Table N, what fraction of a

radioactive 90Sr sample would remain

unchanged after 56.2 years?

1) 1212

2) 1414

3) 1818

4) 116116

17. How many days are required for 200. grams of

radon-222 to decay to 50.0 grams?

1) 1.91 days 3) 7.64 days

2) 3.82 days 4) 11.5 days

18. Which radioisotope undergoes beta decay and

has a half-life of less than 1 minute?

1) Fr-220 3) N-16

2) K-42 4) P-32

19. Based on Reference Table N, what fraction of a

sample of gold-198 remains radioactive after

2.69 days?

1) 1414

2) 1212

3) 3434

4) 7878

20. After 32 days, 5 milligrams of an 80-milligram

sample of a radioactive isotope remains

unchanged. What is the half-life of this element?

1) 8 days 3) 16 days

2) 2 days 4) 4 days

21. According to Reference Table N, which

radioactive isotope will retain only one-eighth (1818

) its original radioactive atoms after

approximately 43 days?

1) gold-198 3) phosphorus-32

2) iodine-131 4) radon-222

22. According to Table N, which radioactive isotope

is best for determining the actual age of Earth?

1) 238U

2) 90Sr

3) 60Co

4) 14C

Base your answers to questions 23 through 26 on on

the graph below. The graph represents the decay of

radioactive material X into a stable decay product.

23. If radioactive material X were heated, the length

of its half-life period would

1) decrease 3) remain the same

2) increase

24. Each of the objects below has different amounts

remaining of the original radioactive material X.

Which object is most likely the oldest?

1)

2)

3)

4)

25. Which graph best represents the relative

percentages of radioactive material X and its

stable decay product after 15,000 years?(The

shaded region represents radioactive material

while the non-shaded region represents stable

decay products.)

1)

3)

2)

4)

26. What is the approximate half-life of radioactive

material X?

1) 5,000 yr 3) 50,000 yr

2) 10,000 yr 4) 100,000 yr

27. Exactly how much time must elapse before 16

grams of potassium-42 decays, leaving 2 grams

of the original isotope?

1) 8 12.4 hours 3) 3 12.4 hours

2) 2 12.4 hours 4) 4 12.4 hours

28. As a sample of the radioactive isotope 131I

decays, its half-life

1) decreases 3) remains the same

2) increases

29. The half-life of a radioactive substance is 2.5

minutes. What fraction of the original

radioactive substance remains after 10 minutes?

1) 1

2

2) 1

4

3) 1

8

4) 1

16

30. Approximately what fraction of an original

Co60 sample remains after 21 years?

1) 1

2

2) 1

4

3) 1

8

4) 1

16

31. The half-life of 131I is 8.07 days. What fraction

of a sample of 131I remains after 24.21 days?

1) 1

2

2) 1

4

3) 1

8

4) 1

16

32. What was the original mass of a radioactive

sample that decayed to 25 grams in four half-life

periods?

1) 50 g 3) 200 g

2) 100 g 4) 400 g

33. What is the total number of grams of a 32-gram

sample of 32P remaining after 71.5 days of

decay?

1) 1.0 g 3) 8.0 g

2) 2.0 g 4) 4.0 g

34. In how many days will a 12-gram sample of 13153 I

decay, leaving a total of 1.5 grams of the

original isotope?

1) 8.0 3) 20.

2) 16 4) 24

35. What mass of a 60.0-gram sample of 16N will

remain unchanged after 28.8 seconds?

1) 3.75 g 3) 15.0 g

2) 7.50 g 4) 30.0 g

36. The half-life of 146 C is 5,730 years. What fraction

of a 1 gram sample of 146 C would remain after

17,190 years?

1) 1

2

2) 1

4

3) 1

8

4) 1

16

37. What is the number of half-life periods required

for a sample of a radioactive material to decay to

one-sixteenth its original mass?

1) 8 3) 3

2) 16 4) 4

38. A sample of 131I decays to 1.0 gram in 40. days.

What was the mass of the original sample?

1) 8.0 g 3) 32 g

2) 16 g 4) 4.0 g

39. Compared to 37K, the isotope 42K has a

1) shorter half-life and the same decay mode

2) shorter half-life and a different decay mode

3) longer half-life and the same decay mode

4) longer half-life and a different decay mode

40. What total mass of a 16 gram sample of 60Co

will remain unchanged after 15.9 years?

1) 1.0 g 3) 8.0 g

2) 2.0 g 4) 4.0 g

41. A 40.0 milligram sample of 33P decays to 10.0

milligrams in 50.0 days. What is the half-life of 33P?

1) 12.5 days 3) 37.5 days

2) 25.0 days 4) 75.0 days

42. If 8.0 grams of a sample of 60Co existed in 1990,

in which year will the remaining amount of 60Co

in the sample be 0.50 gram?

1) 1995 3) 2006

2) 2000 4) 2011

43. If 3.0 grams of 90Sr in a rock sample remained in

1989, approximately how many grams of 90Sr

were present in the original rock sample in 1933?

1) 9.0 g 3) 3.0 g

2) 6.0 g 4) 12. g

44. As a sample of a radioactive element decays, its

half-life

1) decreases 3) remains the same

2) increases

45. If 80 milligrams of a radioactive element decays

to 10 milligrams in 30 minutes, what is the

element's half-life in minutes?

1) 10 3) 30

2) 20 4) 40

46. An 80 milligram sample of a radioactive isotope

decays to 5 milligrams in 32 days. What is the

half-life of this element?

1) 8 days 3) 16 days

2) 2 days 4) 4 days

47. If a radioactive substance has a half-life of 9

days what fraction of its original mass would

remain after 27 days?

1) 1

8

2) 1

4

3) 1

2

4) 3

4

48. The graph below represents the decay of a

radioactive isotope.

Based on Reference Table H, which

radioisotope is best represented by the graph?

1) 32P

2) 131I

3) 198Au

4) 222Rn

49. Which sample will decay least over a period of

30 days?

1) 10 g of Au-198 3) 10 g of P-32

2) 10 g of I-131 4) 10 g of Rn-222

50. As the temperature of a sample of a radioactive

element decreases, the half-life of the element

1) decreases 3) remains the same

2) increases

51. Which radioactive sample would contain the

greatest remaining mass of the radioactive

isotope after 10 years?

1) 2.0 grams of 198Au

2) 2.0 grams of 42K

3) 4.0 grams of 32P

4) 4.0 grams of 60Co

52. The graph below represents the decay curve of a

radioactive isotope. The half-life of this isotope

is

1) 8 years 3) 45 years

2) 30 years 4) 60 years

53. After 30 days, 5.0 grams of a radioactive isotope

remains from an original 40.-gram sample. What

is the half-life of this element?

1) 5 days 3) 15 days

2) 10 days 4) 20 days

54. Approximately how many grams of a 40-gram

sample of 13153 I will remain unchanged after 24

days?

1) 5 3) 13

2) 10 4) 20

55. The half-life of a radioactive isotope is 20.0

minutes. What is the total amount of a 1.00-

gram sample of this isotope remaining after 1.00

hour?

1) 0.500 g 3) 0.250 g

2) 0.333 g 4) 0.125 g

56. Which of the following radioisotopes has the

shortest half-life?

1) 14C

2) 3H

3) 37K

4) 32P

57. A radioactive element has a half-life of 2 days.

Which fraction represents the amount of an

original sample of this element remaining after 6

days?

1) 1

8

2) 1

2

3) 1

3

4) 1

4

58. Which of the following 10-gram samples of

radioisotope will decay to the greatest extent in

28 days?

1) 3215P

2) 8536Kr

3) 22087 Fr

4) 13153 I

59. An original sample of a radioisotope had a mass

of 10 grams. After 2 days, 5 grams of the

radioisotope remains unchanged. What is the

half-life of this radioisotope?

1) 1 day 3) 5 days

2) 2 days 4) 4 days

60. The decay of which radioisotope can be used to

estimate the age of the fossilized remains of an

insect?

1) Rn-222 3) Co-60

2) I-131 4) C-14

61. Which isotope is most commonly used in the

radioactive dating of the remains of organic

materials?

1) 14C

2) 16N

3) 32P

4) 37K

62. Which isotopic ratio needs to be determined

when the age of ancient wooden objects is

investigated?

1) uranium-235 to uranium-238

2) hydrogen-2 to hydrogen-3

3) nitrogen-16 to nitrogen-14

4) carbon-14 to carbon-12

63. Which procedure is based on the half-life of a

radioisotope?

1) accelerating to increase kinetic energy

2) radiating to kill cancer cells

3) counting to determine a level of radioactivity

4) dating to determine age

64. A radioactive-dating procedure to determine the

age of a mineral compares the mineral's

remaining amounts of isotope 238U and isotope

1) 206Pb

2) 206Bi

3) 214Pb

4) 214Bi

65. The course of a chemical reaction can be traced

by using a

1) polar molecule 3) stable isotope

2) diatomic molecule 4) radioisotope

66. The radioisotope I-131 is used to

1) control nuclear reactors

2) determine the age of fossils

3) diagnose thyroid disorders

4) trigger fussion reactors

67. Radioisotopes used for medical diagnosis must

have

1) long half-lives and be quickly eliminated by

the body

2) long half-lives and be slowly eliminated by

the body

3) short half-lives and be quickly eliminated by

the body

4) short half-lives and be slowly eliminated by

the body

68. A radioisotope which is sometimes used by

doctors to pinpoint a brain tumor is

1) carbon-12 3) technetium-99

2) lead-206 4) uranium-238

Reference Tables

Reference Tables

Reference Tables

Reference Tables

Answer KeyAnswer Key

1. 1

2. 4

3. 2

4. 2

5. 2

6. 2

7. 1

8. 4

9. 1

10. 4

11. 2

12. 4

13. 2

14. 132132 or 0.3125

15. 3

16. 2

17. 3

18. 3

19. 2

20. 1

21. 3

22. 1

23. 3

24. 1

25. 3

26. 1

27. 3

28. 3

29. 4

30. 4

31. 3

32. 4

33. 1

34. 4

35. 1

36. 3

37. 4

38. 3

39. 4

40. 2

41. 2

42. 4

43. 4

44. 3

45. 1

46. 1

47. 1

48. 2

Answer Key

49. 3

50. 3

51. 4

52. 2

53. 2

54. 1

55. 4

56. 3

57. 1

58. 3

59. 2

60. 4

61. 1

62. 4

63. 4

64. 1

65. 4

66. 3

67. 3

68. 3