Radioactivity and Nuclear Chemistry

Introductory Chemistry, 3rd EditionNivaldo Tro : Roy Kennedy Massachusetts Bay Community College Wellesley Hills, MA Introductory Chemistry, 3rd EditionNivaldo Tro Chapter 17 Radioactivity and Nuclear Chemistry 2009, Prentice Hall

The Discovery of Radioactivity : Tro's Introductory Chemistry, Chapter 17 2 The Discovery of Radioactivity Antoine-Henri Becquerel designed an experiment to determine if phosphorescent minerals also gave off x-rays.

The Discovery of Radioactivity, Continued : Tro's Introductory Chemistry, Chapter 17 3 The Discovery of Radioactivity, Continued Bequerel discovered that certain minerals were constantly producing penetrating energy rays he called uranic rays. Like x-rays. But not related to fluorescence. Bequerel determined that: All the minerals that produced these rays contained uranium. The rays were produced even though the mineral was not exposed to outside energy. Energy apparently being produced from nothing?

The Curies : Tro's Introductory Chemistry, Chapter 17 4 The Curies Marie Curie used an electroscope to detect the radiation of uranic rays in samples. By carefully separating minerals into their components, she discovered new elements by detecting the radiation they emitted. Radium named for its green phosphorescence. Polonium named for her homeland. Since the radiation was no longer just emitted from of uranium, she renamed it radioactivity.

Electroscope : Tro's Introductory Chemistry, Chapter 17 5 Electroscope

Properties of Radioactivity : Tro's Introductory Chemistry, Chapter 17 6 Properties of Radioactivity Radioactive rays can ionize matter. Cause uncharged matter to become charged. Basis of Geiger counter and electroscope. Radioactive rays have high energy. Radioactive rays can penetrate matter. Radioactive rays cause phosphorescent chemicals to glow. Basis of scintillation counter.

What Is Radioactivity? : Tro's Introductory Chemistry, Chapter 17 7 What Is Radioactivity? Release of tiny, high-energy particles from an atom. Particles are ejected from the nucleus.

Types of Radioactive Rays : Tro's Introductory Chemistry, Chapter 17 8 Types of Radioactive Rays Rutherford discovered there were three types of radioactivity: 1. Alpha rays (a): Have a charge of +2 c.u. and a mass of 4 amu. What we now know to be helium nucleus. 2. Beta rays (b): Have a charge of -1 c.u. and negligible mass. Electron-like. 3. Gamma rays (g): Form of light energy (not particle like a and b).

Rutherford’s Experiment : Tro's Introductory Chemistry, Chapter 17 9 Rutherford’s Experiment ++++++++++++ --------------

Penetrating Ability of Radioactive Rays : Tro's Introductory Chemistry, Chapter 17 10 Penetrating Ability of Radioactive Rays 0.01 mm 1 mm 100 mm Pieces of lead

Order of Strength of Ionizing and Penetrating Ability : Tro's Introductory Chemistry, Chapter 17 11 Order of Strength of Ionizing and Penetrating Ability Ionizing ability = a > b > g. Penetrating ability = a < b < g.

Facts About the Nucleus : Tro's Introductory Chemistry, Chapter 17 12 Facts About the Nucleus Very small volume compared to volume of the atom. Essentially entire mass of atom. Very dense. Composed of protons and neutrons that are tightly held together. Nucleons.

Facts About the Nucleus, Continued : Tro's Introductory Chemistry, Chapter 17 13 Facts About the Nucleus, Continued Every atom of an element has the same number of protons; equal to the atomic number (Z). Atoms of the same elements can have different numbers of neutrons. Isotopes. Different atomic masses. Isotopes are identified by their mass number (A). Mass number = number of protons + neutrons.

Facts About the Nucleus, Continued : Tro's Introductory Chemistry, Chapter 17 14 Facts About the Nucleus, Continued The number of neutrons is calculated by subtracting the atomic number from the mass number. The nucleus of an isotope is called a nuclide. Less than 10% of the known nuclides are non-radioactive, most are radionuclides. Each nuclide is identified by a symbol. Element − mass number = X − A.

Important Atomic Symbols : 15 Important Atomic Symbols

Radioactivity : Tro's Introductory Chemistry, Chapter 17 16 Radioactivity Radioactive nuclei spontaneously decompose into smaller nuclei. Radioactive decay. We say that radioactive nuclei are unstable. The parent nuclide is the nucleus that is undergoing radioactive decay; the daughter nuclide are the new nuclei that are made. Decomposing involves the nuclide emitting a particle and/or energy. All nuclides with 84 or more protons are radioactive.

Transmutation : 17 Transmutation Rutherford discovered that during the radioactive process, atoms of one element are changed into atoms of a different element—transmutation. Dalton’s atomic theory Statement 3. In order for one element to change into another, the number of protons in the nucleus must change.

Chemical Processes vs. Nuclear Processes : Tro's Introductory Chemistry, Chapter 17 18 Chemical Processes vs. Nuclear Processes Chemical reactions involve changes in the electronic structure of the atom. Atoms gain, lose, or share electrons. No change in the nuclei occurs. Nuclear reactions involve changes in the structure of the nucleus. When the number of protons in the nucleus changes, the atom becomes a different element.

Nuclear Equations : Tro's Introductory Chemistry, Chapter 17 19 Nuclear Equations We describe nuclear processes using nuclear equations. Use the symbol of the nuclide to represent the nucleus. Atomic numbers and mass numbers are conserved. Use this fact to predict the daughter nuclide if you know parent and emitted particle.

Alpha Emission : Tro's Introductory Chemistry, Chapter 17 20 Alpha Emission An  particle contains 2 protons and 2 neutrons. Helium nucleus. Loss of an alpha particle means: Atomic number decreases by 2. Mass number decreases by 4.

a Decay : Tro's Introductory Chemistry, Chapter 17 21 a Decay

Beta Emission : Tro's Introductory Chemistry, Chapter 17 22 Beta Emission A  particle is like an electron. Moving much faster. Produced from the nucleus. When an atom loses a  particle, its: Atomic number increases by 1. Mass number remains the same. In beta decay, a neutron changes into a proton.

b Decay : Tro's Introductory Chemistry, Chapter 17 23 b Decay

Gamma Emission : Tro's Introductory Chemistry, Chapter 17 24 Gamma Emission Gamma (g) rays are high-energy photons of light. No loss of particles from the nucleus. No change in the composition of the nucleus, however, the arrangement of the nucleons changes. Same atomic number and mass number. Generally occurs after the nucleus undergoes some other type of decay and the remaining particles rearrange.

Positron Emission : Tro's Introductory Chemistry, Chapter 17 25 Positron Emission Positron has a charge of 1+ c.u. and negligible mass. Anti-electron. When an atom loses a positron from the nucleus, its: Mass number remains the same. Atomic number decreases by 1. Positrons appear to result from a proton changing into a neutron.

b+ Decay : Tro's Introductory Chemistry, Chapter 17 26 b+ Decay

Particle Changes : Tro's Introductory Chemistry, Chapter 17 27 Particle Changes

What Kind of Decay and How Many Protons and Neutrons Are in the Daughter? : Tro's Introductory Chemistry, Chapter 17 28 What Kind of Decay and How Many Protons and Neutrons Are in the Daughter? Alpha emission giving a daughter nuclide with 9 protons and 7 neutrons. 11 p+ 9 n0

What Kind of Decay and How Many Protons and Neutrons Are in the Daughter?, Continued : Tro's Introductory Chemistry, Chapter 17 29 What Kind of Decay and How Many Protons and Neutrons Are in the Daughter?, Continued Beta emission giving a daughter nuclide with 10 protons and 11 neutrons. 9 p+ 12 n0

What Kind of Decay and How Many Protons and Neutrons Are in the Daughter?, Continued : Tro's Introductory Chemistry, Chapter 17 30 What Kind of Decay and How Many Protons and Neutrons Are in the Daughter?, Continued Positron emission giving a daughter nuclide with 4 protons and 5 neutrons. 5 p+ 4 n0

Nuclear Equations : Tro's Introductory Chemistry, Chapter 17 31 Nuclear Equations In the nuclear equation, mass numbers and atomic numbers are conserved. We can use this fact to determine the identity of a daughter nuclide if we know the parent and mode of decay.

Example—Write the Nuclear Equation for Positron Emission from C-11. : Tro's Introductory Chemistry, Chapter 17 32 Example—Write the Nuclear Equation for Positron Emission from C-11. 1. Write the nuclide symbols for both the starting radionuclide and the particle.

Example—Write the Nuclear Equation for Positron Emission from C-11, Continued. : Tro's Introductory Chemistry, Chapter 17 33 Example—Write the Nuclear Equation for Positron Emission from C-11, Continued. 2. Set up the equation. Emitted particles are products. Captured particles are reactants.

Example—Write the Nuclear Equation for Positron Emission from C-11, Continued. : Tro's Introductory Chemistry, Chapter 17 34 Example—Write the Nuclear Equation for Positron Emission from C-11, Continued. 3. Determine the mass number and atomic number of the missing nuclide. Mass and atomic numbers are conserved.

Example—Write the Nuclear Equation for Positron Emission from C-11, Continued. : Tro's Introductory Chemistry, Chapter 17 35 Example—Write the Nuclear Equation for Positron Emission from C-11, Continued. 4. Determine the element from the atomic number.

Practice—Write a Nuclear Equation for Each of the Following: : Tro's Introductory Chemistry, Chapter 17 36 Practice—Write a Nuclear Equation for Each of the Following: Alpha emission from Th-238. Beta emission from Ne-24. Positron emission from N-13.

Practice—Write a Nuclear Equation for Each of the Following, Continued: : Tro's Introductory Chemistry, Chapter 17 37 Alpha emission from Th-238. Beta emission from Ne-24. Positron emission from N-13. Practice—Write a Nuclear Equation for Each of the Following, Continued:

Detecting Radioactivity : Tro's Introductory Chemistry, Chapter 17 38 Detecting Radioactivity To detect when a phenomenon is present, you need to identify what it does: Radioactive rays can expose light-protected photographic film. Use photographic film to detect the presence of radioactive rays—film badges.

Detecting Radioactivity, Continued : Tro's Introductory Chemistry, Chapter 17 39 Detecting Radioactivity, Continued 2. Radioactive rays cause air to become ionized. An electroscope detects radiation by its ability to penetrate the flask and ionize the air inside. Geiger-Müller counter works by counting electrons generated when Ar gas atoms are ionized by radioactive rays.

Detecting Radioactivity, Continued : Tro's Introductory Chemistry, Chapter 17 40 Detecting Radioactivity, Continued 3. Radioactive rays cause certain chemicals to give off a flash of light when they strike the chemical. A scintillation counter is able to count the number of flashes per minute.

Natural Radioactivity : Tro's Introductory Chemistry, Chapter 17 41 Natural Radioactivity There are small amounts of radioactive minerals in the air, ground, and water. It’s even in the food you eat! The radiation you are exposed to from natural sources is called background radiation.

Half-Life : Tro's Introductory Chemistry, Chapter 17 42 Half-Life Each radioactive isotope decays at a unique rate. Some fast, some slow. Not all the atoms of an isotope change simultaneously. Rate is a measure of how many of them change in a given period of time. Measured in counts per minute, or grams per time. The length of time it takes for half of the parent nuclides in a sample to undergo radioactive decay is called the half-life.

Half-Lives of Various Nuclides : Tro's Introductory Chemistry, Chapter 17 43 Half-Lives of Various Nuclides

How “Hot” Is It? : Tro's Introductory Chemistry, Chapter 17 44 How “Hot” Is It? When we speak of a sample being hot, we are referring to the number of decays we get per minute. For samples with equal numbers of radioactive atoms, the sample with the shorter half-life will be hotter. That is, more atoms will change in a given period of time.

Half-Life : 45 Half-Life Half of the radioactive atoms decay each half-life.

Slide 46 : 46

How Long Is the Half-Life of this Radionuclide? : Tro's Introductory Chemistry, Chapter 17 47 How Long Is the Half-Life of this Radionuclide?

Example 17.4—How Long Does It Take for a 1.80 mol Sample of Th-228 to Decay to 0.225 mol? (Half-Life Is 1.9 Years.) : 48 Example 17.4—How Long Does It Take for a 1.80 mol Sample of Th-228 to Decay to 0.225 mol? (Half-Life Is 1.9 Years.) It is easiest to draw a table showing the amount of Th-228 as a function of the number of half-lives. It takes three half-lives, or 5.7 years, to reach 0.225 mol. To get next line in Amount of Th-238 column,  2. To get next line in Time (yrs) column, + 1 half-life.

Practice—Radon-222 Is a Gas that Is Suspected of Causing Lung Cancer as It Leaks into Houses. It Is Produced by Uranium Decay. Assuming No Loss or Gain from Leakage, if There Is 1024 g of Rn-222 in the House Today, How Much Will There be in 5.4 Weeks? ( Rn-222 Half-Life Is 3.8 Days.) : Tro's Introductory Chemistry, Chapter 17 49 Practice—Radon-222 Is a Gas that Is Suspected of Causing Lung Cancer as It Leaks into Houses. It Is Produced by Uranium Decay. Assuming No Loss or Gain from Leakage, if There Is 1024 g of Rn-222 in the House Today, How Much Will There be in 5.4 Weeks? ( Rn-222 Half-Life Is 3.8 Days.)

Practice—Radon-222 Is a Gas that Is Suspected of Causing Lung Cancer as It Leaks into Houses. It Is Produced by Uranium Decay. Assuming No Loss or Gain from Leakage, if There Is 1024 g of Rn-222 in the House Today, How Much Will There be in 5.4 Weeks? ( Rn-222 Half-Life Is 3.8 Days.), Continued : 50 Practice—Radon-222 Is a Gas that Is Suspected of Causing Lung Cancer as It Leaks into Houses. It Is Produced by Uranium Decay. Assuming No Loss or Gain from Leakage, if There Is 1024 g of Rn-222 in the House Today, How Much Will There be in 5.4 Weeks? ( Rn-222 Half-Life Is 3.8 Days.), Continued 5.4 weeks x 7 days/wk = 37.8  38 days

Practice—How Long Is the Half-Life of an Isotope if a Sample of the Isotope that Registers 60,000 cpm on the Geiger Counter Decays to 15,000 cpm After 150 Minutes? : Tro's Introductory Chemistry, Chapter 17 51 Practice—How Long Is the Half-Life of an Isotope if a Sample of the Isotope that Registers 60,000 cpm on the Geiger Counter Decays to 15,000 cpm After 150 Minutes?

Practice—How Long Is the Half-Life of an Isotope if a Sample of the Isotope that Registers 60,000 cpm on the Geiger Counter Decays to 15,000 cpm After 150 Minutes?, Continued : Tro's Introductory Chemistry, Chapter 17 52 Since it takes 2 half-lives, divide 150 by 2. Practice—How Long Is the Half-Life of an Isotope if a Sample of the Isotope that Registers 60,000 cpm on the Geiger Counter Decays to 15,000 cpm After 150 Minutes?, Continued Fill in the “Amount…” and “Number of half-lives” columns first, then divide the final time by the number of half-lives.

Practice—How Much of a Radioactive Isotope (with Half-Life of 10 Minutes) Did You Start with if After One Hour You Have 2 g? : Tro's Introductory Chemistry, Chapter 17 53 Practice—How Much of a Radioactive Isotope (with Half-Life of 10 Minutes) Did You Start with if After One Hour You Have 2 g?

Practice—How Much of a Radioactive Isotope (with Half-Life of 10 Minutes) Did You Start with if After One Hour You Have 2 g?, Continued : 54 Practice—How Much of a Radioactive Isotope (with Half-Life of 10 Minutes) Did You Start with if After One Hour You Have 2 g?, Continued Fill in the “Number of half-lives” and “Time…” columns first, then work backwards up the “Amount…” column.

Decay Series : Tro's Introductory Chemistry, Chapter 17 55 Decay Series In nature, often one radioactive nuclide changes in another radioactive nuclide. Daughter nuclide is also radioactive. All of the radioactive nuclides that are produced one after the other until a stable nuclide is made is called a decay series. To determine the stable nuclide at the end of the series without writing it all out: Count the number of a and b decays. From the mass nunmber, subtract 4 for each a decay. From the atomic number, subtract 2 for each a decay and add 1 for each b.

U-238 Decay Series : Tro's Introductory Chemistry, Chapter 17 56 U-238 Decay Series

Practice—Write All the Steps in the U-238 Decay Series and Identify the Stable Isotope at the End of the Series. : Tro's Introductory Chemistry, Chapter 17 57 Practice—Write All the Steps in the U-238 Decay Series and Identify the Stable Isotope at the End of the Series. a, b, b, a, a, a, a, b, a, b, a, b, b, a

Practice—Write All the Steps in the U-238 Decay Series and Identify the Stable Isotope at the End of the Series, Continued. : Tro's Introductory Chemistry, Chapter 17 58 Practice—Write All the Steps in the U-238 Decay Series and Identify the Stable Isotope at the End of the Series, Continued. a, b, b, a, a, a, a, b, a, b, a, b, b, a Daughter Granddaughter Great granddaughter Great great granddaughter

Practice—Determine the Stable Isotope at the End of the U-238 Decay Series. : Tro's Introductory Chemistry, Chapter 17 59 Practice—Determine the Stable Isotope at the End of the U-238 Decay Series. a, b, b, a, a, a, a, b, a, b, a, b, b, a

Practice—Determine the Stable Isotope at the End of the U-238 Decay Series, Continued. : Tro's Introductory Chemistry, Chapter 17 60 Practice—Determine the Stable Isotope at the End of the U-238 Decay Series, Continued. a, b, b, a, a, a, a, b, a, b, a, b, b, a

Object Dating : Tro's Introductory Chemistry, Chapter 17 61 Object Dating Mineral (geological). Compare the amount of U-238 to Pb-206. Compare amount of K-40 to Ar-40. Archeological (once living materials). Compare the amount of C-14 to C-12. C-14 radioactive with half-life = 5730 years. While substance is living, C-14/C-12 is fairly constant. CO2 in air is ultimate source of all C in body. Atmospheric chemistry keeps producing C-14 at the same rate it decays. Once dies, C-14/C-12 ratio decreases. Limit up to 50,000 years.

Radiocarbon DatingC-14 Half-Life = 5730 Years : 62 Radiocarbon DatingC-14 Half-Life = 5730 Years

Radiocarbon Dating : 63 Radiocarbon Dating

Example 17.5—A Skull Believed to Belong to an Early Human Being Is Found to Have a C-14 Content 3.125% of that Found in Living Organisms. How Old Is the Skull? : Tro's Introductory Chemistry, Chapter 17 64 Example 17.5—A Skull Believed to Belong to an Early Human Being Is Found to Have a C-14 Content 3.125% of that Found in Living Organisms. How Old Is the Skull? From Table 17.2, when the concentration of C-14 is 3.125% of that found in living organisms, the age of the object is 28,560 years.

Nonradioactive Nuclear Changes : Tro's Introductory Chemistry, Chapter 17 65 Nonradioactive Nuclear Changes A few nuclei are so unstable, that if their nuclei are hit just right by a neutron, the large nucleus splits into two smaller nuclei. This is called fission. Small nuclei can be accelerated to such a degree that they overcome their charge repulsion and smash together to make a larger nucleus. This is called fusion. Both fission and fusion release enormous amounts of energy. Fusion releases more energy per gram than fission.

Fission : Tro's Introductory Chemistry, Chapter 17 66 Fission

Fission Chain Reaction : Tro's Introductory Chemistry, Chapter 17 67 Fission Chain Reaction A chain reaction occurs when a reactant in the process is also a product of the process. In the fission process it is the neutrons. So you only need a small amount of neutrons to start the chain. Many of the neutrons produced in the fission are either ejected from the uranium before they hit another U-235 or are absorbed by the surrounding U-238. Minimum amount of fissionable isotope needed to sustain the chain reaction is called the critical mass.

Fission Chain Reaction, Continued : Tro's Introductory Chemistry, Chapter 17 68 Fission Chain Reaction, Continued

Fissionable Material : Tro's Introductory Chemistry, Chapter 17 69 Fissionable Material Fissionable isotopes include U-235, Pu-239, and Pu-240. Natural uranium is less than 1% U-235. The rest is mostly U-238. Not enough U-235 to sustain chain reaction. To produce fissionable uranium the natural uranium must be enriched in U-235: To about 7% for “weapons grade.” To about 3% for “reactor grade.”

Nuclear Power : Tro's Introductory Chemistry, Chapter 17 70 Nuclear Power Nuclear reactors use fission to generate electricity. About 20% of U.S. electricity. The fission of U-235 produces heat. The heat boils water, turning it to steam. The steam turns a turbine, generating electricity.

Nuclear Power Plants vs. Coal-Burning Power Plants : Tro's Introductory Chemistry, Chapter 17 71 Nuclear Power Plants vs. Coal-Burning Power Plants Use about 50 kg of fuel to generate enough electricity for 1 million people. No air pollution. Use about 2 million kg of fuel to generate enough electricity for 1 million people. Produces NO2 and SOx that add to acid rain. Produces CO2 that adds to the greenhouse effect.

Nuclear Power Plants—Core : Tro's Introductory Chemistry, Chapter 17 72 Nuclear Power Plants—Core The fissionable material is stored in long tubes, called fuel rods, arranged in a matrix. Subcritical. Between the fuel rods are control rods made of neutron absorbing material. B and/or Cd. Neutrons needed to sustain the chain reaction. The rods are placed in a material to slow down the ejected neutrons, called a moderator. Allows chain reaction to occur below critical mass.

Pressurized Light Water Reactor (PLWR) : Tro's Introductory Chemistry, Chapter 17 73 Pressurized Light Water Reactor (PLWR) Design used in U.S. (GE, Westinghouse). Water is both the coolant and moderator. Water in core kept under pressure to keep it from boiling. Fuel is enriched uranium. Subcritical. Containment dome of concrete.

Nuclear Power Plant : 74 Nuclear Power Plant

PLWR : 75 PLWR Core Containment building Turbine Condenser Cold water Boiler

PLWR—Core : 76 PLWR—Core Cold water Fuel rods Hot water

Concerns About Nuclear Power : Tro's Introductory Chemistry, Chapter 17 77 Concerns About Nuclear Power Core melt-down. Water loss from core, heat melts core. China syndrome. Chernobyl. Waste disposal. Waste highly radioactive. Reprocessing, underground storage? Federal High Level Radioactive Waste Storage Facility at Yucca Mountain, Nevada. Delay in opening, 2017? Transporting waste. How do we deal with nuclear power plants that are no longer safe to operate?

Nuclear Fusion : Tro's Introductory Chemistry, Chapter 17 78 Nuclear Fusion Fusion is the combining of light nuclei to make a heavier one. The sun uses the fusion of hydrogen isotopes to make helium as a power source. Requires high input of energy to initiate the process. Because need to overcome repulsion of positive nuclei. Produces 10x the energy per gram as fission. No radioactive byproducts. Unfortunately, the only currently working application is the H-bomb.

Fusion : Tro's Introductory Chemistry, Chapter 17 79 Fusion

Biological Effects of Radiation : Tro's Introductory Chemistry, Chapter 17 80 Biological Effects of Radiation Radiation is high energy, energy enough to knock electrons from molecules and break bonds. Ionizing radiation. Energy transferred to cells can damage biological molecules and cause malfunction of the cell.

Acute Effects of Radiation : Tro's Introductory Chemistry, Chapter 17 81 Acute Effects of Radiation High levels of radiation over a short period of time kill large numbers of cells. From a nuclear blast or exposed reactor core. Causes weakened immune system and lower ability to absorb nutrients from food. May result in death, usually from infection.

Chronic Effects : Tro's Introductory Chemistry, Chapter 17 82 Chronic Effects Low doses of radiation over a period of time show an increased risk for the development of cancer. Radiation damages DNA that may not get repaired properly. Low doses over time may damage reproductive organs, which may lead to sterilization. Damage to reproductive cells may lead to a genetic defect in offspring.

Factors that Determine Biological Effects of Radiation : Tro's Introductory Chemistry, Chapter 17 83 Factors that Determine Biological Effects of Radiation The more energy the radiation has, the larger its effect. The better the radiation penetrates human tissue, the deeper the potential effect. Gamma >> beta > alpha. The more ionizing the radiation, the greater the effect of the radiation. Alpha > beta > gamma. The radioactive half-life of the radionuclide. The biological half-life of the element. The physical state of the radioactive material.

Biological Effects of Radiation : Tro's Introductory Chemistry, Chapter 17 84 Biological Effects of Radiation The amount of danger to humans of radiation is measured in the unit rems.

Radiation Exposure : Tro's Introductory Chemistry, Chapter 17 85 Radiation Exposure

Medical Uses of Radioisotopes,Diagnosis : Tro's Introductory Chemistry, Chapter 17 86 Medical Uses of Radioisotopes,Diagnosis Isotope scanners. Certain organs absorb most or all of a particular element. Can measure the amount absorbed by using tagged isotopes of the element and a Geiger counter, film, or a scintillation counter. Use radioisotope with short half-life. Use radioisotope low ionizing. Beta or gamma.

Radioisotopes Used for Diagnosis : Tro's Introductory Chemistry, Chapter 17 87 Radioisotopes Used for Diagnosis

Medical Uses of Radioisotopes:Diagnosis : Tro's Introductory Chemistry, Chapter 17 88 Medical Uses of Radioisotopes:Diagnosis PET scan. Positron emission tomography. Brain scan and function.

Medical Uses of Radioisotopes:Treatment—Radiotherapy : Tro's Introductory Chemistry, Chapter 17 89 Medical Uses of Radioisotopes:Treatment—Radiotherapy Cancer treatment. Cancer cells are more sensitive to radiation than healthy cells. Brachytherapy. Place radioisotope directly at site of cancer. Teletherapy. Use gamma radiation from Co-60 outside to penetrate inside. Radiopharmaceutical therapy. Use radioisotopes that concentrate in one area of the body.

Gamma Ray Treatment : Tro's Introductory Chemistry, Chapter 17 90 Gamma Ray Treatment