Question 1

A newly synthesized element is found to have a half-life of 3.82 minutes. How long after its formation will the activity be only 10% of original activity?

Accepted Answer

A)  12.1 min 
B)  6.03 min 
C)  0.603 min 
D)  12.7 min 
E)  1.27 min 
A)  12.1 min 
B)  6.03 min 
C)  0.603 min 
D)  12.7 min 
E)  1.27 min

Question 2

Which of the following statements concerning alpha decay is INCORRECT?

Accepted Answer

A)  It involves nuclides with atomic number larger than 83 and mass number larger than 200. 
B)  It has great penetrating power, but little ionizing power. 
C)  It often leaves the nucleus in an excited state. 
D)  The atomic number decreases by two. 
E)  The alpha particle is made up of two protons and two neutrons. 
A)  It involves nuclides with atomic number larger than 83 and mass number larger than 200. 
B)  It has great penetrating power, but little ionizing power. 
C)  It often leaves the nucleus in an excited state. 
D)  The atomic number decreases by two. 
E)  The alpha particle is made up of two protons and two neutrons.

Question 3

Choose the correct word to describe the nuclear stability of the following isotope. If it is radioactive, choose the most likely mode of decay. 238U

Accepted Answer

A)  radioactive, beta 
B)  radioactive, fission 
C)  radioactive, alpha 
D)  radioactive, neutron 
E)  stable 
A)  radioactive, beta 
B)  radioactive, fission 
C)  radioactive, alpha 
D)  radioactive, neutron 
E)  stable

Question 4

Fission is the process of combining small nuclei into larger nuclei.

Accepted Answer

A) True 
 B)False

Question 5

Radioactive decay is:

Accepted Answer

A)  temperature independent 
B)  a second-order process 
C)  a zero-order process 
D)  a process with a large activation energy 
A)  temperature independent 
B)  a second-order process 
C)  a zero-order process 
D)  a process with a large activation energy

Question 6

Choose the INCORRECT statement.

Accepted Answer

A)  Radioactive 32P as a phosphate can be used to trace the uptake of phosphorus in plants. 
B)  The thyroid gland can be studied by the use of radioactive iodine. 
C)  There is no difference in physical properties between isotopes. 
D)  The mechanism of a chemical reaction can be followed by a radioactive tracer such as 35S. 
E)  Industrial catalysts can be followed by a tracer such as 192Ir. 
A)  Radioactive 32P as a phosphate can be used to trace the uptake of phosphorus in plants. 
B)  The thyroid gland can be studied by the use of radioactive iodine. 
C)  There is no difference in physical properties between isotopes. 
D)  The mechanism of a chemical reaction can be followed by a radioactive tracer such as 35S. 
E)  Industrial catalysts can be followed by a tracer such as 192Ir.

Question 7

Which of the following are true for alpha particles? I) α particles are equivalent to 2   + 2   .
II) α decay decreases the atomic number by four.
III) α particles are deflected more strongly than e- by magnetic fields, but in the opposite direction.
IV) α particles are easily stopped as they strike matter.

Accepted Answer

A)  I and II 
B)  I, II, III 
C)  I and III 
D)  I and IV 
E)  I, II, III, and IV 
A)  I and II 
B)  I, II, III 
C)  I and III 
D)  I and IV 
E)  I, II, III, and IV

Question 8

The charcoal from ashes found in a cave gave 7.4 14C counts per gram per minute. Wood from the outer portion of a growing tree gives a comparable count of 15.3. The half-life of 14C is 5700 years. How old are the ashes?

Accepted Answer

A)  5700 y 
B)  5437 y 
C)  3245 y 
D)  9220 y 
E)  5970 y 
A)  5700 y 
B)  5437 y 
C)  3245 y 
D)  9220 y 
E)  5970 y

Question 9

210Pb → 4He + ________

Accepted Answer

A)  214Pb 
B)  206Hg 
C)  214Hg 
D)  206Pb 
E)  206Br 
A)  214Pb 
B)  206Hg 
C)  214Hg 
D)  206Pb 
E)  206Br

Question 10

Choose the correct statement.

Accepted Answer

A)  Instability leading to decay by alpha particle emission is found mostly in nuclides of very large mass number. 
B)  Decay by beta emission is confined to nuclides of very low mass number. 
C)  Ejection of an electron by a nuclide results in a nuclide of next lower mass number. 
D)  All radiations emitted by radioactive nuclides consist of charged, high energy particles. 
E)  Many alpha and beta emissions are followed by gamma emissions. 
A)  Instability leading to decay by alpha particle emission is found mostly in nuclides of very large mass number. 
B)  Decay by beta emission is confined to nuclides of very low mass number. 
C)  Ejection of an electron by a nuclide results in a nuclide of next lower mass number. 
D)  All radiations emitted by radioactive nuclides consist of charged, high energy particles. 
E)  Many alpha and beta emissions are followed by gamma emissions.

Question 11

Choose the INCORRECT statement.

Accepted Answer

A)  Geiger-Müller counters detect radiation by the ionization caused in the gas in the counter. 
B)  Bubble chambers detect radiation by the ionization trail left by the radiation. 
C)  Radiation causes no harm to the human body. 
D)  Radiation kills cancer cells more easily than normal cells. 
E)  Alpha particles are less penetrating than beta particles. 
A)  Geiger-Müller counters detect radiation by the ionization caused in the gas in the counter. 
B)  Bubble chambers detect radiation by the ionization trail left by the radiation. 
C)  Radiation causes no harm to the human body. 
D)  Radiation kills cancer cells more easily than normal cells. 
E)  Alpha particles are less penetrating than beta particles.

Question 12

Which of the following would have the greatest penetrating power through matter?

Accepted Answer

A)  gamma rays 
B)  alpha particles 
C)  protons 
D)  beta particles 
E)  positron particles 
A)  gamma rays 
B)  alpha particles 
C)  protons 
D)  beta particles 
E)  positron particles

Question 13

The initial decay rate of a nuclide is 1.77 × 1012/m. After 7.63 d, the decay rate is 1.82 × 1011/m. What is the half-life of the isotope?

Accepted Answer

A)  139 d 
B)  0.298 d 
C)  0.207 d 
D)  2.32 d 
E)  2.50 d 
A)  139 d 
B)  0.298 d 
C)  0.207 d 
D)  2.32 d 
E)  2.50 d

Question 14

The half-life of 238U, which decomposes to 206Pb, is 4.51 × 109 y. A rock contains equal masses of these two isotopes. How old is this rock?

Accepted Answer

A)  4.07 × 109 y 
B)  4.06 × 109 y 
C)  9.02 × 109 y 
D)  4.51 × 109 y 
E)  5.00 × 109 y 
A)  4.07 × 109 y 
B)  4.06 × 109 y 
C)  9.02 × 109 y 
D)  4.51 × 109 y 
E)  5.00 × 109 y

Question 15

If the decay constant for 131I is 9.98 x 10-7 s-1, calculate the activity of a 1.00 mg sample.

Accepted Answer

A)  4.59 x 1012 atoms/s 
B)  4.73 x 1012 atoms/s 
C)  4.61 x 1024 atoms/s 
D)  9.98 x 10-4 atoms/s 
A)  4.59 x 1012 atoms/s 
B)  4.73 x 1012 atoms/s 
C)  4.61 x 1024 atoms/s 
D)  9.98 x 10-4 atoms/s

Question 16

Radioactive decay series decay by alpha and positron emission.

Accepted Answer

A) True 
 B)False

Question 17

Choose the INCORRECT statement.

Accepted Answer

A)  An isotope that will fission when hit by a neutron is said to be fertile. 
B)  A moderator slows down neutrons. 
C)  Control rods absorb energy to control the fission reaction. 
D)  Electrons dislodged from an atom or molecule by alpha or beta particles are called primary electrons. 
E)  Radiation exposes photographic film the same as light. 
A)  An isotope that will fission when hit by a neutron is said to be fertile. 
B)  A moderator slows down neutrons. 
C)  Control rods absorb energy to control the fission reaction. 
D)  Electrons dislodged from an atom or molecule by alpha or beta particles are called primary electrons. 
E)  Radiation exposes photographic film the same as light.

Question 18

In the case of radioactive element X, which decays by electron emission with a half-life of 4 days to a stable nuclide of element Z:

Accepted Answer

A)  2 g of element X is required to produce 1.5 g of element Z after 8 days 
B)  element Z will weigh considerably less than element X after decay is complete because of the loss of electrons 
C)  element Z will weigh more than element X when decay is complete since Z has the higher atomic number 
D)  after 8 days the sample will consist of one-fourth element Z and three-fourths element X 
E)  after 8 days element X will be all element Z 
A)  2 g of element X is required to produce 1.5 g of element Z after 8 days 
B)  element Z will weigh considerably less than element X after decay is complete because of the loss of electrons 
C)  element Z will weigh more than element X when decay is complete since Z has the higher atomic number 
D)  after 8 days the sample will consist of one-fourth element Z and three-fourths element X 
E)  after 8 days element X will be all element Z

Question 19

Find the INCORRECT nuclear reaction.

Accepted Answer

A)    +
  →
  +
  + 3
  
B)    +
  →
  +
  
C)    +
  →
  +
  
D)    +
  →
  +
  +
  
E)    +
  →
  
A)    +
  →
  +
  + 3
  
B)    +
  →
  +
  
C)    +
  →
  +
  
D)    +
  →
  +
  +
  
E)    +
  →

Question 20

Choose the correct word to describe the nuclear stability of the following isotope. If it is radioactive, choose the most likely mode of decay. 197Au

Accepted Answer

A)  radioactive, beta 
B)  radioactive, fission 
C)  radioactive, alpha 
D)  radioactive, neutron 
E)  stable 
A)  radioactive, beta 
B)  radioactive, fission 
C)  radioactive, alpha 
D)  radioactive, neutron 
E)  stable

Exam 25: Nuclear Chemistry 1-41

A newly synthesized element is found to have a half-life of 3.82 minutes. How long after its formation will the activity be only 10% of original activity?

Which of the following statements concerning alpha decay is INCORRECT?

Choose the correct word to describe the nuclear stability of the following isotope. If it is radioactive, choose the most likely mode of decay. 238U

Fission is the process of combining small nuclei into larger nuclei.

Radioactive decay is:

Choose the INCORRECT statement.

The charcoal from ashes found in a cave gave 7.4 14C counts per gram per minute. Wood from the outer portion of a growing tree gives a comparable count of 15.3. The half-life of 14C is 5700 years. How old are the ashes?

210Pb → 4He + ________

Choose the correct statement.

Choose the INCORRECT statement.

Which of the following would have the greatest penetrating power through matter?

The initial decay rate of a nuclide is 1.77 × 1012/m. After 7.63 d, the decay rate is 1.82 × 1011/m. What is the half-life of the isotope?

The half-life of 238U, which decomposes to 206Pb, is 4.51 × 109 y. A rock contains equal masses of these two isotopes. How old is this rock?

If the decay constant for 131I is 9.98 x 10-7 s-1, calculate the activity of a 1.00 mg sample.

Radioactive decay series decay by alpha and positron emission.

Choose the INCORRECT statement.

In the case of radioactive element X, which decays by electron emission with a half-life of 4 days to a stable nuclide of element Z:

Find the INCORRECT nuclear reaction.

Choose the correct word to describe the nuclear stability of the following isotope. If it is radioactive, choose the most likely mode of decay. 197Au

Matter - Its Properties and Measurement

Atoms and the Atomic Theory

Chemical Compounds

Chemical Reactions

Introduction to Reactions in Aqueous Solutions

Gases

Thermochemistry

Electrons in Atoms

The Periodic Table and Some Atomic Properties

Chemical Bonding I: Basic Concepts

Chemical Bonding II: Additional Aspects

Intermolecular Forces: Liquids and Solids

Solutions and Their Physical Properties

Chemical Kinetics

Principles of Chemical Equilibrium

Acids and Bases

Additional Aspects of Acid-Base Equilibria

Solubility and Complex-Ion Equilibria

Spontaneous Change: Entropy and Free Energy

Electrochemistry

Main Group Elements I: Groups 1, 2, 13, and 14

Main Group Elements II: Groups 18, 17, 16, 15, and Hydrogen

The Transition Elements

Complex Ions and Coordination Compounds

Structures of Organic Compounds

Reactions of Organic Compounds

Chemistry of the Living State

Filters

The initial decay rate of a nuclide is 1.77 × 10¹²/m. After 7.63 d, the decay rate is 1.82 × 10¹¹/m. What is the half-life of the isotope?

The half-life of 238U, which decomposes to 206Pb, is 4.51 × 10⁹ y. A rock contains equal masses of these two isotopes. How old is this rock?

If the decay constant for 131I is 9.98 x 10^-7 s-1, calculate the activity of a 1.00 mg sample.