Ch.19 - Nuclear ChemistryWorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Radioactive reactions deal with the chemical instability of the nucleus in an atom. 

Nuclear Reactions

Heavy (large atomic mass) elements undergo radioactive reactions in order to increase the stability of their nuclei. 

Concept #1: Understanding Nuclear Reactions. 

In a typical stoichiometric reaction we begin with elements as reactants and end with the same elements in different forms as products. 

In a nuclear reaction the number of protons in an element are affected and so the identity of the element changes. 

The three most common types of radioactive reactions are alpha decay or capture, beta decay or capture and gamma emission

Concept #2: Types of Nuclear Reactions. 

In a radioactive decay or emission reaction the radioactive particle is ejected from the nucleus and forms a product.  

In a radioactive capture or absorption reaction the radioactive particle is taken into the element and so is seen as a reactant. 

Alpha Decay

An alpha particle is comprised of 2 protons and 2 neutrons. 

Concept #3: Understanding Alpha Decay or Emission.

An alpha decay or alpha emission occurs when an unstable nucleus ejects an alpha particle to create a new element. 

Concept #4: The Alpha Particle. 

The alpha particle is one of the largest radioactive particles with the highest ionizing power, but lowest penetrating power. 

Example #1: Write balanced nuclear equations for each of the following alpha emissions.

a) Curium (Cm) – 248

b) Bismuth (Bi) – 207 

Beta Decay

A beta particle has no atomic mass and is represented by an electron. 

Concept #5: Understanding Beta Decay or Emission. 

A beta decay or beta emission occurs when an unstable nucleus ejects a beta particle to create a new element. 

Concept #6: The Beta Particle. 

Beta particles are smaller in size, and therefore have more penetrating power. Luckily, they are less radioactively damaging because of their lower ionizing power. 

Example #2: Write balanced nuclear equations for each of the following beta emissions.

a) Magnesium (Mg) – 25

b) Ruthenium (Ru) – 102 

Example #3: Pb – 208 is formed from Th -232. How many alpha and beta decays have occurred?

  1. 6, 2
  2. 6, 6
  3. 6, 4
  4. 4, 6
  5. 8, 2
Gamma Emission

A gamma particle has no atomic mass and no atomic number and is represented by the sign gamma. 

Concept #7: Understanding Gamma Radiation. 

Gamma radiation is involved in the electromagnetic spectrum. Gamma rays possess the highest energy, while radio waves have lowest energy in terms of the spectrum.  

Concept #8: The Gamma Particle.

The gamma particle does not create a new element like the other radioactive particles, but instead causes the excitation of electrons within an element. 

Gamma Particles have lowest ionizing power, but are the most dangerous because of their highest penetrating power. 

Example #4: Which of the following represents an element that has experienced a gamma emission?

  1. Cl: 1s22s22p63s23p5
  2. Be: 1s22s2
  3. Na: 1s22s22p63p1
  4. N: 1s22s22p3
Electron Capture

Concept #9: Understanding Electron Capture. 

In an electron capture or electron absorption reaction our electron particle is a reactant and not a product. 

Example #5: Write balanced nuclear equations for each of the following elements after undergoing electron capture.

 

a) Rutherfordium (Rf) – 263

b) Nobelium (No) – 260

c) Lead (Pb) – 207

Positron Emission

A positron particle is referred to as the anti-electron particle because it looks like a positively charged electron. 

Concept #10: Understanding Positron Emission. 

A positron decay or positron emission occurs when an unstable nucleus ejects a positron particle to create a new element. 

Example #6: Write balanced nuclear equations for each of the following positron emissions.

a) Uranium (U) – 235

b) Radon (Rn) – 222 

Example #7: A nuclide of Th-225 undergoes 3 alpha decays, 4 beta decays, and a gamma emission. What is the product?

a.  Radium

b.  Radon

c.   Actinium

d.  Cadmium

e.   Antimony 

Additional Problems
The outcome of positron emission and electron capture is the same; i.e., the atomic number is reduced by one. 1. False 2. True
Uranium-238 decays spontaneously by consecutive emissions into what is believed to be a different uranium isotope. What series of emissions has most likely occurred? (a) alpha, beta, alpha (b) alpha, beta, beta (c) beta, beta, beta (d) alpha, beta, gamma (e) it is not possible for one uranium isotope to decay into another
Which one of the following forms of radiation can penetrate the deepest into body tissue? a) alpha (b) beta (c) gamma (d) positron (e) proton
Americium-241 is used in a number of smoke detectors; as this radioisotope decays it causes particles to ionize, conduct an electric current and thereby cause the alarm to buzz. The complete decay of Am 241 involves (successively) α, α, β, α, α, β, α, α, α, β, α and β production.    1. The isotope that undergoes the first β particle emission is: a) U-233   b) Pa-233 c) Pa-239 d) Am-241       2. The isotope obtained when Am-241 has completed this decay sequence is: a) Pb-208 b) Re-205 c) Bi-209 d) Au-209  
In the 232Th decay series, there are six α particles and four β particles lost. What is the final product?   a) 207Pb b) 208Pb c) 210Po d) 206Pb e) 210Bi
Technetium-97 can be produced by absorption of 2H and emission of two neutrons. What is the starting nuclide?   a) 97Mo b) 98Ru c) 97Ru d) 96Nb e) 96Mo 
What particle is emitted when a neon-19 nucleus decays to fluorine-19? (a) alpha (b) beta (c) neutron (d) positron (e) proton
The thorium-232 decay series begins with the emission of an alpha particle. If the daughter decays by beta emission, what is the resulting nuclide?
Relative penetrating abilities of alpha, beta, and gamma radiation.Why are alpha rays much more dangerous when the source of radiation is located inside the body?
Identical amounts of two different nuclides, an alpha emitter and a gamma emitter, with roughly equal half-lives are spilled in a building adjacent to your bedroom.Which of the two nuclides poses the greater health threat to you while you sleep in your bed?
Identical amounts of two different nuclides, an alpha emitter and a gamma emitter, with roughly equal half-lives are spilled in a building adjacent to your bedroom.If you accidentally wander into the building and ingest equal amounts of the two nuclides, which of the two is likely to pose the greater health threat?
Which type of radioactive decay converts a neutron into a proton?
The steps below show three of the steps in the radioactive decay chain for 90232Th. The half-life of each isotope is shown below the symbol of the isotope. Identify the type of radioactive decay for the step (i).
Badge dosimeters monitor the extent to which the individual has been exposed to high-energy radiation. The radiation dose is determined from the extent of darkening of the film in the dosimeter. Which type of radiation-alpha, beta, or gamma-is likely to fog a film that is sensitive to X rays?
The steps below show three of the steps in the radioactive decay chain for 90232Th. The half-life of each isotope is shown below the symbol of the isotope. Which of the isotopes shown has the highest activity?
The steps below show three of the steps in the radioactive decay chain for 90232Th. The half-life of each isotope is shown below the symbol of the isotope. Which of the isotopes shown has the lowest activity?
The steps below show three of the steps in the radioactive decay chain for 90232Th. The half-life of each isotope is shown below the symbol of the isotope. Identify the type of radioactive decay for the step (ii).
The steps below show three of the steps in the radioactive decay chain for 90232Th. The half-life of each isotope is shown below the symbol of the isotope. Identify the type of radioactive decay for the step (iii).
Describe the process of each radioactive decay and a description of how the atomic and mass numbers change.
Consider the graphical representation of a series of decays shown here. The arrow labeled x and the arrow labeled y each correspond to what kind of decay?
Choose symbols for a proton, a neutron, and an electron.
Rank alpha particles, beta particles, positrons, and gamma rays in terms of increasing ionizing power.
Rank alpha particles, beta particles, positrons, and gamma rays in terms of increasing penetrating power.
Explain the significance of the biological effectiveness factor in measuring radiation exposure. What types of radiation would you expect to have the highest biological effectiveness factor?
Which of the following statements best explains why alpha emission is relatively common, but proton emission is extremely rare?
What do all nuclear reactions have in common and how do they differ from each other?
Two students are discussing whether or not the total mass changes during a nuclear reaction. The first student insists that mass is conserved. The second student says that mass is converted into energy.Explain the context in which each student is correct and how that fact is applied to solve problems.
What is radioactivity? Who discovered it? How was it discovered?
Explain the concept of half-life with respect to radioactive nuclides. What rate law is characteristic of radioactivity?
The products of a nuclear reaction usually have a different mass than the reactants. Why?
How does radiation affect living organisms?
Explain why different kinds of radiation affect biological tissues differently, even though the amount of radiation exposure may be the same.
Describe some of the medical uses, both in diagnosis and in treatment of disease, of radioactivity.
The steps below show three of the steps in the radioactive decay chain for 90232Th. The half-life of each isotope is shown below the symbol of the isotope. The next step in the decay chain is an alpha emission. What is the next isotope in the chain?
Write all the balanced nuclear equation for each step of the nuclear decay sequence that starts with U-238 and ends with U-234.Complete the second step. 23490 Th  →  23491 Pa + ?
The naturally occurring radioactive decay series that begins with 92235 U stops with formation of the stable 82207 Pb nucleus. The decays proceed through a series of alpha-particle and beta-particle emissions.How many of alpha-particle emissions are involved in this series?
The naturally occurring radioactive decay series that begins with 92235 U stops with formation of the stable 82207 Pb nucleus. The decays proceed through a series of alpha-particle and beta-particle emissions.How many of beta-particle emissions are involved in this series?
Fill in the missing particles in each of the following nuclear equations. 94241 Pu  →  95241 Am + ____
Fill in the missing particles in each of the following nuclear equations.1119 Na →  1019 Ne + ____
Fill in the missing particles in each of the following nuclear equations.3475 Se + _____ →  3375 As
A breeder nuclear reactor is a reactor in which nonfissile U-238 is converted into fissile Pu-239. The process involves bombardment of U-238 by neutrons to form U-239 which then undergoes two sequential beta decays.Write nuclear equations to represent this process.
Radon-222 decays to a stable nucleus by a series of three alpha emissions and two beta emissions.What is the stable nucleus that is formed?
A 25.0-mL sample of 0.050 M barium nitrate solution was mixed with 25.0 mL of 0.050 M sodium sulfate solution labeled with radioactive sulfur-35. The activity of the initial sodium sulfate solution was 1.22 106 Bq/mL. After the resultant precipitate was removed by filtration, the remaining filtrate was found to have an activity of 250 Bq/mL.Write a balanced chemical equation for the reaction that occurred.
In addition to the natural radioactive decay series that begins with U-238 and ends with Pb-206, there are natural radioactive decay series that begin with U-235 and with Th-232. Both of these series end with nuclides of Pb. Predict the likely end product of each series and the number of alpha decay steps that occur.Predict the likely end product of U-235 series.
In addition to the natural radioactive decay series that begins with U-238 and ends with Pb-206, there are natural radioactive decay series that begin with U-235 and with Th-232. Both of these series end with nuclides of Pb. Predict the likely end product of each series and the number of alpha decay steps that occur.Predict the likely end product of Th-232 series.
Balance the following nuclear reaction and identify the type of radioactive decay. 
Which is the heaviest of the common radioactive particles?1. beta2. positron3. neutron4. gamma5. alpha
Write a nuclear equation for the indicated decay of each of the following nuclides. Express your answer as a nuclear equation.Ra−210 (alpha)Sn−126 (beta)Th−234 (beta)Mn−49 (positron emission)Ar−37 (electron capture)
What is the daughter nucleus produced a. when 217(At) undergoes alpha decay?b. when 103(Mo) undergoes beta decay?c. when 188(Hg) undergoes positron emission?
Complete these nuclear reactions.
Match the characteristics with the correct type of radiation:
Write a nuclear equation for the indicated decay of each of the following nuclides. Express each as a nuclear equation.a. Po-210 (alpha)b. Ac-227 (beta)c. Th-234 (beta)d. O-15 (positron emission)e. Pd-103 (electron capture)
How does a nuclear reaction differ from a chemical reaction?a. In a nuclear reaction, the elements change identities while in a chemical reaction they do not.b.  Entropy is increased in a chemical reaction while it is decreased in a nuclear reaction.c. There is no actual difference between the two reactions except that a nuclear reaction emits radiation while a chemical reaction emits heat.d. Entropy is increased in a nuclear reaction while it is decreased in a chemical reaction.e. In a chemical reaction, elements are created and destroyed while all elements are conserved in a nuclear reaction.
Many nuclides with atomic numbers greater than 83 decay by processes such as electron emission. Explain the observation that the emissions from these unstable nuclides also normally include α particles.
Give the symbol for the following.a proton
Which of the various particles (α particles, β particles, and so on) that may be produced in a nuclear reaction are actually nuclei?
The two most common isotopes of uranium are 235U and 238U. 238U undergoes radioactive decay to 234Th. How many protons, electrons, and neutrons are gained or lost by the 238U atom during this process?
Which form of radioactive decay would you be most likely to detect if it was happening in the room next to the one you are currently in?a) alphab) betac) gammad) positron emission
You may want to reference (Pages 930 - 933)Section 21.9 while completing this problem.Which are classified as ionizing radiation: X rays, alpha particles, microwaves from a cell phone, and gamma rays?
It has been suggested that strontium-90 (generated by nuclear testing) deposited in the hot desert will undergo radioactive decay more rapidly because it will be exposed to much higher average temperatures.Does the process of radioactive decay have an activation energy, like the Arrhenius behavior of many chemical reactions?
Strontium-90 and radon-222 both pose serious health risks. 90Sr decays by β-particle production and has a relatively long half-life (28.9 years). Radon-222 decays by α-particle production and has a relatively short half-life (3.82 days). Explain why each decay process poses health risks.
Were organisms a billion years ago exposed to more or less ionizing radiation than similar organisms today? Explain.
What are the two principal differences between nuclear reactions and ordinary chemical changes?
Write a brief description or definition of the following:(a) nucleon
Write a brief description or definition of the following:(f) nuclide
Drugstores in many areas now carry tablets, under such trade names as Iosat and NoRad, designed to be taken in the event of an accident at a nuclear power plant or a terrorist attack that releases radioactive material. These tablets contain potassium iodide (KI). Can you explain the nature of the protection that they provide?
What are the types of radiation emitted by the nuclei of radioactive elements?
Fill in the missing particles in each of the following nuclear equations.95241 Am  →   93237 Np + _____
The radioactive decay of thorium-232 occurs in multiple steps, called a radioactive decay chain. The second product produced in this chain is actinium-228. Which of the following processes could lead to this product starting with thorium-232?(a) Alpha decay followed by beta emission(b) Beta emission followed by electron capture(c) Positron emission followed by alpha decay(d) Electron capture followed by positron emission(e) More than one of the above is consistent with the observed transformation.
237Np is the parent nuclide of a decay series that starts with α emission, followed by β− emission, and then two more α emissions. Write a balanced nuclear equation for each step.
Why is helium found in deposits of uranium and thorium ores? What kind of radioactive emission produces it?
In a natural decay series, how many α and β− emissions per atom of uranium-235 result in an atom of lead-207?  
Write three nuclear equations to represent the nuclear decay sequence that begins with the alpha decay of U-235 followed by a beta decay of the daughter nuclide and then another alpha decay. Write the first nuclear equation from this sequence.
Write an equation describing the radioactive decay of the following nuclide. (The particle produced is shown in parentheses, except for electron capture, where an electron is a reactant.)b. 83Li (β followed by α)
In the following radioactive decay process, supply the missing particle.a. 60Co → 60Ni + ?
In the following radioactive decay process, supply the missing particle.b. 97Tc + ? → 97Mo
In the following radioactive decay process, supply the missing particle.c. 99Tc → 99Ru + ?
In the following radioactive decay process, supply the missing particle.d. 239Pu → 235U + ?
Supply the missing particle, and state the type of decay for the following nuclear process.
Write a nuclear reaction for each step in the formation of  21884 Po from 23898 U, which proceeds by a series of decay reactions involving the step-wise emission of α, β, β, α, α, α particles, in that order.
Write a nuclear reaction for each step in the formation of   20882 Pb from  22890 Th, which proceeds by a series of decay reactions involving the step-wise emission of α, α, α, α, β, β, α particles, in that order.
In the following radioactive decay process, supply the missing particle.a. 73Ga → 73Ge + ?
In the following radioactive decay process, supply the missing particle.b. 192Pt → 188Os + ?
In the following radioactive decay process, supply the missing particle.c. 205Bi → 205Pb + ?
In the following radioactive decay process, supply the missing particle.d. 241Cm + ? → 241Am
Uranium-235 undergoes a series of α-particle and β-particle productions to end up as lead-207. How many α particles and β particles are produced in the complete decay series?
Some 24395Am was present when Earth formed, but it all decayed in the next billion years. The first three steps in this decay series are emissions of an α particle, a β− particle, and another α particle. What other isotopes were present on the young Earth in a rock that contained some 24395Am?
The radioactive isotope 247Bk decays by a series of α-particle and β-particle productions, taking 247Bk through many transformations to end up as  207Pb. In the complete decay series, how many α particles and β particles are produced?
One type of commercial smoke detector contains a minute amount of radioactive americium-241 (241Am), which decays by α-particle production. The α particles ionize molecules in the air, allowing it to conduct an electric current. When smoke particles enter, the conductivity of the air is changed and the alarm buzz.b. The complete decay of 241Am involves successively α, α, β, α, α, β, α, α, α, β, α, and β production. What is the final stable nucleus produced in this decay series?
One type of commercial smoke detector contains a minute amount of radioactive americium-241 (241Am), which decays by α-particle production. The α particles ionize molecules in the air, allowing it to conduct an electric current. When smoke particles enter, the conductivity of the air is changed and the alarm buzz.a. Write the equation for the decay of 24195Am by α-particle production.b. The complete decay of 241Am involves successively α, α, β, α, α, β, α, α, α, β, α, and β production. What is thefinal stable nucleus produced in this decay series?c. Identify the 11 intermediate nuclides.
Potassium-40 can decay to produce Ar-40. What is the method of decay?
Thorium-232 is known to undergo a progressive decay series until it reaches stability at lead-208. For each step of the series indicated in the table below, which nuclear particle is emitted?
Potassium-40 can decay to produce Ar-40. Enter the nuclear equation for this decay.
Isotope such as  26Al (half-life: 7.2 × 10 5 years) are believed to have been present in our solar system as it formed, but have since decayed and are now called extinct nuclide.(a) 26Al decays by β+ emission or electron capture. Write the equations for these two nuclear transformations.
Write a balanced equation for the following nuclear reaction:(a) bismuth-212 decays into polonium-212
Write a balanced equation for the following nuclear reaction:(c) neptunium-239 forms from the reaction of uranium-238 with a neutron and then spontaneously converts into plutonium-239
Write a balanced equation for the following nuclear reaction:(d) strontium-90 decays into yttrium-90
In the naturally occurring thorium-232 decay series, the steps emit this sequence of particles: α, β−, β−, α, α, α, α, β−, β−  and α. Write a balanced equation for each step.
Write a balanced equation for the following nuclear reaction:(a) mercury-180 decays into platinum-176
Write a balanced equation for the following nuclear reaction:(c) thorium-232 decays and produces an alpha particle and a radium-228 nucleus, which decays into actinium-228 by beta decay
Write a balanced equation for the following nuclear reaction:(d) neon-19 decays into fluorine-19
Enter balanced nuclear equations for the following transformations.Gold-201 decays to a mercury isotope.
You may want to reference (Pages 903 - 905) Section 21.1 while completing this problem.What particle is produced during the following decay processes?(a) sodium-24 decays to magnesium-24;
A radioactive decay series that begins with 90232Th ends with the formation of the stable nuclide 82208Pb.How many alpha-particle emissions are involved in the sequence of radioactive decays (assuming only alpha decay and beta decay will take place)?
A radioactive decay series that begins with 90232Th ends with the formation of the stable nuclide 82208Pb.How many beta-particle emissions are involved in the sequence of radioactive decays?
Write the balanced nuclear equation for the reaction represented by the diagram shown here.
Write a partial decay series for Th-232 undergoing the following sequential decays: alphaα, β, β, α
Complete the following table with the nuclear particle that is produced in each nuclear reaction.
Complete the following equation by adding the missing specie:(c) 147 N + 42He  ⟶ ? + 11 H
Complete the following equation:(b) 146 C ⟶ 147 N + ?
Technetium-99 is prepared from  98Mo. Molybdenum-98 combines with a neutron to give molybdenum-99, an unstable isotope that emits a β particle to yield an excited form of technetium-99, represented as  99 Tc*. This excited nucleus relaxes to the ground state, represented as 99 Tc, by emitting a γ ray. The ground state of  99 Tc then emits a β particle. Write the equations for each of these nuclear reactions.
Write a partial decay series for Rn-220 undergoing the following sequential decays: alphaα, α, β, β
Identify the product of radioactive decay and classify the given nuclear reaction accordingly (α decay, β decay or γ decay).
Fill in the blanks in the partial decay series. Express your answers as a chemical expression.Part A24194Pu → 24195Am +                 Part B24195Am → 23793Np +                  
Complete and balance the following nuclear equations. Express your answer as a nuclear equation.
What is the activity of a 45.9 mu Ci sample of carbon-14 in becquerels?
Complete these nuclear reactions.