Chapter 24

List the different types of radiation and their charges.

Explain how you know whether the reaction is chemical or nuclear when an atom undergoes a reaction and attains a more-stable form.

Write a balanced nuclear equation for the reaction in which oxygen-15 undergoes positron emission.

Thorium- 229 is used to increase the lifetime of fluorescent bulbs. What type of decay occurs when thorium-229 decays to form radium-225?

Bandages can be sterilized by exposure to gamma radiation from cobalt--60, which has a half-life of 5.27 y. How much of a 10.0 -mg sample of cobalt--60 is left after one half-life? Two half-lives? Three half-lives?

If the passing of five half-lives leaves 25.0 \(\mathrm{mg}\) of a strontium-90 sample, how much was present in the beginning?

Describe what happens to unstable nuclei.

Explain how you can predict whether or not an isotope is likely to be stable if you know its number of neutrons and protons.

Describe the forces acting on the particles within a nucleus and explain why neutrons are the glue holding the nucleus together.

Predict the nuclear equation for the alpha decay of radium- 226 used on the tips of older lighthing rods.

Calculate how much of a 10.0 -g sample of americium-241 remains after four half-lives. Americium- 241 is a radioisotope commonly used in smoke detectors and has a half-life of 430 y.

Calculate After 2.00 y, 1.986 g of a radioisotope remains from a sample that had an original mass of 2.000 \(\mathrm{g} .\) a. Calculate the half-life. b. How much of the radioisotope remains after 10.00 y?

Write the balanced nuclear equation for the induced transmutation of alluminum-2 7 into sodium-24 by neutron bombardment. An alpha particle is released in the reaction.

Write the balanced nuclear equation for the alpha-particle bombardment of \(^{239} \mathrm{Pu}\) One of the reaction products is a neutron.

Challenge Archeologists sometimes use a procedure called neutron activation analysis to identify elements in artifacts. The figure at right shows one type of reaction that can occur when an artifact is bombarded with neutrons. If the product of the process is cadmium-110, what was the target and unstable isotope? Write balanced nuclear equations for the process to support your answer.

Compare and contrast nuclear fission and nuclear fusion reactions. Describe the particles that are involved in each type of reaction and the changes they undergo.

Describe the process that occurs during a nuclear chain reaction and explain how to monitor a chain reaction in a nuclear reactor.

Explain how nuclear fission can be used to generate electric power.

Formulate an argument supporting or opposing nuclear power as your state's primary power source. Assume the primary source of power currently is the burning of fossil fuels.

Explain one way in which nuclear chemistry is used to diagnose or treat disease.

Describe several methods used to detect and measure radiation.

Calculate A lab worker receives an average radiation dose of 21 mrem each month. Her allowed dose is \(5,000\) mremly. On average, what fraction of her yearly dose does she receive?

Calculate A lab worker receives an average radiation dose of 21 mrem each month. Her allowed dose is \(5,000\) mremly. On average, what fraction of her yearly dose does she receive?

Compare and contrast chemical reactions and nuclear reactions in terms of energy changes and the particles involved.

\(\begin{array}{ll}{\text { Match each numbered choice on the right with the }} \\\ {\text { correct radiation type on the left. }} \\ {\text { a. alpha }} & {\text { 1. high-speed electrons }} \\ {\text { b. beta }} & {\text { 2. } 2+\text { charge, blocked easily }} \\ {\text { c. gamma }} & {\text { 3. no charge, electromagnetic radiation }}\end{array}\)

Dental crown Uranium-234 is used to make dental crowns appear brighter. The alpha decay of uranium- 234 produces what isotope?

Colored Glass Thorium \(-230\) can be used to provide coloring in glass objects. One method of producing thorium- 230 is through the radioactive decay of actinium-230. Is this an example of alpha decay or beta decay? How do you know?

What is the strong nuclear force? On which particles does it act?

Explain the difference between positron emission and electron capture.

Categorize each type of radioactive decay. a. Mass number and atomic number are unchanged. b. Mass number remains the same and atomic number decreases.

What is a radioactive decay series? When does it end?

Radioisotopes What are the factors that determine the amount of a given radioisotope in nature?

Calculate the neutron-to-proton ratio for each atom. \(\begin{array}{ll}{\text { a. } \operatorname{tin}-134} & {\text { c. carbon-12 }} \\ {\text { b. silver-107 }} & {\text { d. carbon-1 } 4}\end{array}\)

Complete the following equations. $$_{83}^{214} \mathrm{Bi} \rightarrow_{2}^{4} \mathrm{He}+? \quad \text { b. }^{239} \mathrm{Np} \rightarrow_{94}^{239} \mathrm{Pu}+?$$

Write a balanced nuclear equation for the alpha decay of americium-241.

Write a balanced nuclear equation for the beta decay of cesium-137.

Bone Formation The electron capture of strontium-85 can be used by physicians to study bone formation. Write a balanced nuclear equation for this reaction.

Nuclear mishap The half-life of tritium \(\left(3^{3} \mathrm{H}\right)\) is 12.3 \(\mathrm{y}\) . If 48.0 \(\mathrm{mg}\) of tritium is released from a nuclear power plant during the course of a mishap, what mass of the nuclide will remain after 49.2 y? After 98.4 y?

Static Charge Static charge can interfere with the production of plastic products by attracting dust and dirt. To reduce it, manufacturers expose the area to polonium- \(210,\) which has a half-life of 138 days. How much of a 25.0 -g sample will remain after one year ( 365 days)?

The half-life of polonium-218 is 3.0 \(\mathrm{min.}\) If you start with 20.0 \(\mathrm{g}\) , how long will it be before only 1.0 \(\mathrm{g}\) remains?

An unknown radioisotope exhibits 8540 decays per second. After 350.0 min, the number of decays has decreased to 1250 per second. What is the half-life?

Define transmutation. Are all nuclear reactions also transmutation reactions? Explain.

Relate binding energy per nucleon to mass number.

What is a chain reaction? Give an example of a nuclear chain reaction.

Explain the purpose of control rods in a nuclear reactor.

Why is the fuel of a nuclear reactor enriched?

Explain how it is possible that fission, the splitting of nuclei, and fusion, the combining of nuclei, both release tremendous amounts of energy.

Describe the current limitations of fusion as a power source.

Smoke Detectors Americium-241, a radioisotope used in smoke detectors, is produced by bombarding plutonium- 238 with neutrons to produce plutonium-240, which is bombarded with neutrons to produce plutonium-241. The plutonium- 241 decays to americium-241. Write the balanced nuclear equations for each reaction.

Exit signs Exit signs are coated with a paint containing phosphors. These phosphors are activated by the radio- isotope tritium \((3 \mathrm{H})\) , produced by bombarding lithium-6 with neutrons to produce lithium-7. The lithium- 7 then undergoes alpha decay to produce the tritium. Write balanced nuclear equations for both steps.