Exam Questions Ch9 The Nucleus, Radioactivity, and Nuclear

General, Organic, and Biochemistry, 10e (Denniston)

Chapter 9 The Nucleus, Radioactivity, and Nuclear Medicine

1) A substance is described as being radioactive. What does this indicate about the substance?

A) The substance was formed as a result of the decay of an unstable nucleus.

B) The substance has been exposed to radiation from a decaying nucleus.

C) The substance emits high energy particles or rays from its unstable nucleus.

D) The substance readily absorbs radiation from the radiofrequency region of the electromagnetic spectrum.

E) The substance is extremely small; special radio microscopes are necessary to view it.

2) Which type of radiation is negatively charged?

A) alpha particle

B) beta particle

C) positron

D) gamma ray

E) All radiation types are negatively charged.

3) Which type of radiation emitted by radioactive nuclei has no mass and no charge?

A) alpha particle

B) beta particle

C) positron

D) gamma ray

E) All radiation types have a mass and charge.

4) Which type of radiation has the greatest penetrating power?

A) alpha particle

B) beta particle

C) positron

D) gamma ray

E) All radiation types are equally penetrating.

5) When a molecule is hit by gamma radiation, which of the following is likely to occur?

A) increase in mass

B) decrease in mass

C) ionization

D) swelling

E) replication

6) What product nucleus results from the alpha decay of radium-226?

A) radium-226m

B) thorium-230

C) radon-222

D) radium-230

E) thorium-222

7) The isotope Tc decays to Tc by emitting radiation. What type of radiation is emitted?

A) alpha particle

B) beta particle

C) positron

D) gamma ray

E) neutron

8) What is the nuclear symbol for the isotope formed when N undergoes beta decay?

A) e

B) O

C) C

D) B

E) N

9) What is the correct nuclear symbol for the unknown product "X" in the nuclear equation shown below?

U → X + He

A) Th

B) Ra

C) U

D) Pu

E) Pu

10) Which phrase best describes a metastable isotope?

A) an isotope that is only partially stable

B) an isotope that decays by emitting only a gamma ray

C) an isotope that decays only when prompted by neutron bombardment

D) an isotope that is man-made

E) any isotope of an element that is radioactive

11) What is the name given to the energy that is responsible for holding the protons and neutrons together in the nucleus?

A) nuclear energy

B) kinetic energy

C) static energy

D) binding energy

E) activation energy

12) Unstable nuclei become more stable by spontaneously undergoing a change in their nucleus and emitting radiation. What is the term used to describe this process?

A) stabilization

B) nuclear dissociation

C) radioactive decay

D) nuclear fusion

E) ionization

13) What nuclear process is used in commercial nuclear power plants to produce energy?

A) fusion

B) fission

C) metastable induction

D) radiocarbon dating

E) positron emission tomography

14) Control rods made of cadmium or boron moderate the fission reactions in nuclear power plants. Which of the following best describes how control rods function?

A) Control rods absorb the high heat that is produced from the fission reactions, preventing overheating from occurring.

B) Control rods absorb some of the fast moving neutrons that are produced in the fission reactions, preventing their initiation of other fission reactions.

C) Control rods absorb the steam produced when the water is heated to a high temperature, preventing the generation of electricity.

D) Control rods absorb gamma rays that are responsible for initiating a chain reaction.

E) Control rods act as a catalyst for the reverse of the fission reaction, preventing the fission reaction from continuing.

15) Which radioactive isotope is involved in radiocarbon dating?

A) C-6

B) C-12

C) C-13

D) C-14

E) C-6 and C-12.

16) Why are cancer cells more sensitive to radiation than normal cells?

A) The cells most sensitive to radiation are the ones undergoing rapid cellular division; cancer cells are an example of rapidly dividing cells.

B) The cells most sensitive to radiation are the ones undergoing slow cellular division; cancer cells are an example of slowly dividing cells.

C) The cells most sensitive to radiation are the ones that do not undergo cellular division; cancer cells are an example of cells that do not divide.

D) Cancer cells generally form on top of normal cells; they are therefore the cells closest to the applied radiation.

E) Cancer cells are shielded from radiation by their thick cellular membrane; normal cells lack this cellular membrane.

17) What term is used to describe radioactive substances that are used as probes to study internal organs?

A) isotopes

B) tracers

C) metastable nuclides

D) Geiger counter

E) roentgens

18) Because iodine tends to concentrate in one particular organ of the body, radioactive iodine is often used as a diagnostic tool to determine how this organ is functioning. In which organ does iodine tend to concentrate?

A) liver

B) kidneys

C) brain

D) pancreas

E) thyroid

19) Which is the most widely used radioactive isotope in nuclear medicine?

A) technetium-99m

B) hydrogen-3

C) uranium-235

D) carbon-14

E) plutonium-244

20) A high degree of stability is predicted for nuclei with which of the following characteristics?

A) high neutron/proton ratio (>2)

B) more protons than neutrons

C) even number of protons or neutrons

D) odd number of protons

E) large number of protons (84 or more)

21) What statement concerning the half-life of a radioactive isotope is FALSE?

A) The half-life of a radioactive isotope is the amount of time it takes for one half of the sample to undergo radioactive decay.

B) The stability of a radioactive isotope is indicated by its half-life; isotopes with shorter half-lives are very unstable.

C) A radioactive isotope with a short half-life emits its radiation quickly.

D) The half-life of a particular radioactive isotope decreases as the amount of the radioactive material decreases.

E) Different radioactive isotopes have different decay rates, and therefore have different half-lives.

22) Which statement concerning nuclear reactions and chemical reactions is FALSE?

A) Nuclear reactions involve changes in the protons or neutrons in the nucleus of an atom.

B) Chemical reactions involve changes in the valence electrons of an atom.

C) Nuclear reactions usually result in a change in the identity of the radioactive isotope.

D) Nuclear reactions are capable of producing more energy than chemical reactions.

E) Chemical reactions always occur much faster than nuclear reactions.

23) Why do radiation workers wear a film badge?

A) to measure their cumulative level of exposure to radiation

B) to measure the amount of time they spend in close proximity to radiation

C) to monitor the different types of radiation to which they are being exposed

D) to measure the radioactivity in their blood

E) to quickly determine the amount of radiation given off by a piece of radioactive material with which they are working

24) Which radioactive element is sometimes found in indoor air in such places as basements?

A) polonium

B) thallium

C) uranium

D) radon

E) plutonium

25) The term LD50 represents which of the following?

A) the dosage of toxic material needed to kill 50% of the exposed population in 30 days

B) the number of people killed by 1 mg of a toxic material in one day

C) the number of people killed by 1 mg of a toxic material in 30 days

D) the percentage of people that will die when exposed to 50 mg of a toxic substance

E) the amount of radiation absorbed by the body when standing 50 m from a radioactive substance

26) In the general symbol X for a nucleus, how is the number of neutrons calculated?

A) A + Z

B) A - Z

C) Z - A

D) 2Z - A

E) 2Z + A

27) What is the charge of an alpha particle?

A) 0

B) -1

C) 1

D) 2

E) 4

28) What is the charge of a beta particle?

A) 0

B) -1

C) 1

D) -2

E) 2

29) Which type of radiation emitted by radioactive nuclei is similar in mass to a helium atom?

A) alpha

B) beta

C) gamma

D) delta

E) positron

30) Which of the following best describes the sequence with which nuclear power plants generate energy?

A) nuclear energy → mechanical energy → electrical energy → heat energy

B) nuclear energy → heat energy → mechanical energy → electrical energy

C) electrical energy → mechanical energy → heat energy → nuclear energy

D) mechanical energy → nuclear energy → heat energy → electrical energy

E) heat energy → mechanical energy → electrical energy → nuclear energy

31) Which type of radiation emitted by radioactive nuclei is the slowest moving and least penetrating?

A) alpha

B) beta

C) gamma

D) positron

E) None of the choices are correct.

32) The isotope Ra decays to Rn by emitting radiation. What type of radiation is emitted?

A) alpha

B) beta

C) gamma

D) positron

E) None of the choices are correct.

33) The isotope Ni decays to Cu by emitting radiation. What type of radiation is emitted?

A) alpha

B) beta

C) gamma

D) positron

E) None of the choices are correct.

34) What is the complete nuclear symbol for X in the equation for radioactive decay shown below?

C → N + X

A) e

B) e

C) β

D) γ

E) None of the choices are correct.

35) What percentage of the initial amount of a radioactive isotope will remain after ten half-lives?

A) 0.50%

B) 0.78%

C) 0.36%

D) 0.11%

E) 0.098%

36) The half-life of tritium (H) is 12 years. How long does it take for 16.0 ng of tritium to decay to the point where 2.0 ng remains?

A) 12 years

B) 24 years

C) 36 years

D) 48 years

E) 52 years

37) Phosphorus-31 is a non-radioactive isotope of phosphorus, and phosphorus-32 is a radioactive isotope of phosphorus used in nuclear medicine.  Which statement concerning these two isotopes is TRUE?

A) Both isotopes emit high energy particles or rays known as radiation.

B) The radioactive isotope has one more proton than the non-radioactive isotope.

C) The non-radioactive isotope has 31 neutrons and the radioactive isotope has 32 neutrons.

D) Both isotopes have the same number of protons and neutrons.

E) The non-radioactive isotope has 16 neutrons and the radioactive isotope has 17 neutrons.

38) Which of the following isotopes has no neutrons?

A) H-1

B) H-2

C) H-3

D) He-4

E) C-12

39) Which nuclear particle is identical to an He2+ ion?

A) alpha

B) beta

C) gamma

D) proton

E) electron

40) How many protons are contained in one alpha particle?

A) 0

B) 1

C) 2

D) 4

E) 6

41) How many electrons are contained in an alpha particle?

A) 0

B) 1

C) 2

D) 4

E) 6

42) What does the symbol He represent?

A) an alpha particle

B) a beta particle

C) a gamma ray

D) a positron

E) a deuteron

43) Which radioactive emission can be stopped by a few sheets of paper?

A) alpha

B) beta

C) gamma

D) proton

E) electron

44) What does the symbol e represent?

A) an alpha particle

B) a beta particle

C) a gamma ray

D) a positron

E) a deuteron

45) Which of the following particles or rays requires barriers of lead and/or concrete for adequate protection?

A) alpha

B) beta

C) gamma

D) proton

E) electron

46) What particle or nucleus X is needed to complete the following equation?

Rn → Po + X

A) proton

B) uranium-235

C) alpha

D) beta

E) gamma

47) What particle or nucleus X is needed to complete the following equation?

K → e + X

A) argon-20

B) calcium-20

C) argon-18

D) potassium-40

E) calcium-40

48) When the isotope Bi undergoes alpha decay, what isotope is formed?

A) Ti

B) Au

C) Po

D) Ti

E) Bi

49) When the isotope Bi undergoes beta decay, what isotope is formed?

A) Po

B) Au

C) Po

D) Ti

E) Bi

50) What information is conveyed by the "m" in 99mTc?

A) The mass of the isotope is 99.

B) The isotope is metastable.

C) The isotope is man-made.

D) There are multiple isotopes for this element.

E) This is the most abundant isotope for this element.

51) How many half-lives are needed for a 400.0 ng sample of a radioactive isotope to decay to 12.5 ng?

A) 4

B) 5

C) 10

D) 16

E) 32

52) What fraction of the initial amount of an isotope remains after five half-lives?

A) 0.200

B) 0.969

C) 0.0100

D) 0.0313

E) 1.00 × 10-10

53) A 50-mg sample of iodine-131 was placed in a container 32.4 days ago. If its half-life is 8.1 days, how many milligrams of iodine-131 are now present?

A) 47.3 mg

B) 3.1 mg

C) 3.24 mg

D) 0.81 mg

E) 6.2 mg

54) What nuclear process involves heavy nuclei splitting into lighter nuclei?

A) gamma decay

B) beta decay

C) breeding

D) fission

E) fusion

55) What is the process responsible for energy production in the sun?

A) chemical combustion

B) fission oxidation-reduction

C) decomposition

D) fission

E) fusion

56) What fissionable isotope or element is produced from uranium-238 in a breeder reactor?

A) uranium-235

B) uranium-238m

C) plutonium-239

D) carbon-14

E) hydrogen-3

57) Bombardment of which isotope with high speed neutrons (cosmic radiation) forms carbon-14 in the upper atmosphere? 

A) Li-5

B) U-238

C) O-16

D) O-18

E) N-14

58) Which one of the following radioactive isotopes is used to diagnose coronary disease?

A) thallium-201

B) iodine-131

C) xenon-133

D) uranium-238

E) carbon-14

59) Americium-241 is a radioactive isotope used in smoke detectors. If the symbol for this isotope is Am, which of the following correctly describes its subatomic composition?

A) 241 protons, 241 electrons, 95 neutrons

B) 95 neutrons, 241 protons, 146 electrons

C) 95 protons, 95 electrons, 51 neutrons

D) 146 neutrons, 95 protons, 51 electrons

E) 95 protons, 95 electrons, 146 neutrons

60) Magnetic resonance imaging (MRI) depends on the presence of what type of particles in body tissue?

A) carbon atoms

B) hydrogen atoms

C) water molecules

D) radioactive isotopes

E) magnetic particles

61) Which of the following measures of radioactivity takes into account the relative biological effect (RBE) of the radiation involved?

A) rem

B) rad

C) roentgen

D) curie

E) half-life

62) Give the missing symbol to the following nuclear reaction. C → B + ?

A) α

B) γ

C) e

D) e

E) None of the choices are correct.

63) A 200.0-ng sample of sodium-24 was stored in a lead-lined cabinet for 45 hours. The half-life of sodium-24 is 15 hours. How much sodium-24 remains?

A) 100 ng

B) 75 ng

C) 50 ng

D) 25 ng

E) 13 ng

64) When a nuclear reaction is balanced, which of the following is TRUE?

A) The number of atoms of each element is the same on either side of the reaction arrow.

B) The sum of the mass numbers is the same on either side of the reaction arrow.

C) The sum of the atomic numbers is the same on either side of the reaction arrow.

D) None of the choices are true.

E) Both the sum of the mass numbers and the sum of the atomic numbers are the same on either side of the reaction.

65) Which of the following is not a method used for detecting radiation?

A) Geiger counter

B) photographic imaging

C) film badges

D) computer imaging

E) radiocarbon dating

66) What type of radioactive decay is illustrated by the following nuclear equation?

C → B + e

A) positron emission

B) alpha decay

C) beta decay

D) gamma production

E) helium emission

67) What type of radioactive decay is illustrated by the following nuclear equation?

N → O + e

A) positron emission

B) alpha decay

C) beta decay

D) gamma production

E) helium emission

68) What type of radioactive decay is illustrated by the following nuclear equation?

C → B + He

A) positron emission

B) alpha decay

C) beta decay

D) gamma production

E) helium emission

69) Which statement concerning the stability of nuclei is TRUE?

A) Light elements are stable if their ratio of protons to neutrons is 2:1.

B) Nuclei with 36 or more protons are unstable.

C) Isotopes with even numbers of protons and neutrons are more stable than those with odd numbers of protons and neutrons.

D) All isotopes with more protons than neutrons are stable.

E) Naturally occurring isotopes containing 1, 3, 5, 7, 9…protons or neutrons are stable.

70) The half-life of cobalt-60 is 5.3 years. What percent of a sample of cobalt-60 will remain after 21.2 years?

A) 50%

B) 40%

C) 12.5%

D) 10%

E) 6.25%

71) The mass number of an alpha particle is 4.

72) Beta particles are a form of electromagnetic energy.

73) Gamma rays move at the speed of light.

74) Positrons are produced when a proton is converted to a neutron in the nucleus of a radioactive isotope.

75) A metastable isotope decays by emitting a gamma ray.

76) Compared to the energy of chemical bonds, nuclear binding energy is very weak.

77) Nuclei with 84 or more protons are unstable and radioactive.

78) Isotopes with even numbers of protons and neutrons are generally more stable than those with odd numbers of these particles.

79) A radioactive sample will decay completely in two half-lives.

80) After four half-lives, the fraction of a radioactive isotope remaining is one eighth of the initial amount.

81) The sun's source of energy is nuclear fission.

82) Commercial nuclear power plants use the fusion process to generate electrical energy.

83) When a molecule is hit by gamma radiation, it may become ionized.

84) Doubling the distance from a source of radioactivity will halve the radiation intensity.

85) When the strength of a radioactive source is specified in curies, it provides no information on the biological effects of the radiation.

86) The term LD50 means the dose of toxic material that will be needed to kill 50% of the exposed population within 30 days.