CHAPTER 10 CONCURRENT ENROLLMENT CHEMISTRY

RADIOACTIVE NUCLEI Nuclei that undergo spontaneous changes and emit energy in the form of radiation Nuclei that undergo spontaneous changes and emit energy in the form of radiation Henri Becquerel Henri Becquerel Radioactive decay Radioactive decay A process in which an unstable nucleus changes energy states and in the process emits radiation A process in which an unstable nucleus changes energy states and in the process emits radiation

RADITATION Three types of radiation Three types of radiation Alpha particles 4 2 α or 4 2 He 2+ Alpha particles 4 2 α or 4 2 He 2+ Identical to the helium nucleus, has two protons and two neutrons Identical to the helium nucleus, has two protons and two neutrons Beta particles Beta particles -1 0 β or -1 0 e β or -1 0 e- Identical to an electron but is produced when a nucleus becomes unstable, a neutron changes into a proton by releasing an electron Identical to an electron but is produced when a nucleus becomes unstable, a neutron changes into a proton by releasing an electron Gamma rays Gamma rays 0 0 γ 0 0 γ A high-energy ray that is like an X ray, but is not a particle A high-energy ray that is like an X ray, but is not a particle

Positron and electron capture Daughter nuclei Daughter nuclei radioactive decay The new nuclei produced when unstable nuclei undergo radioactive decay The new nuclei produced when unstable nuclei undergo Positron Positron Positively charged electron, 1 0 e + Positively charged electron, 1 0 e + This is used in PET scans of the brain This is used in PET scans of the brain Proton changes into a neutron Proton changes into a neutron Electron capture Electron capture When an electron from outside the nucleus is drawn into the nucleus, where it combines with a proton to form a neutron When an electron from outside the nucleus is drawn into the nucleus, where it combines with a proton to form a neutron

ISOTOPE HALF-LIFE The time required for one-half the unstable nuclei in a sample to undergo radioactive decay The time required for one-half the unstable nuclei in a sample to undergo radioactive decay Free radical Free radical An electron-deficient particle that is very reactive An electron-deficient particle that is very reactive Radiation sickness Radiation sickness The condition associated with and following short-term exposure to intense radiation The condition associated with and following short-term exposure to intense radiation

MEASUREMENTS Curie Curie Unit of radiation measurement corresponding to 3.7 X nuclear disintegrations per second Unit of radiation measurement corresponding to 3.7 X nuclear disintegrations per second Becquerel Becquerel Unit of radiation measurement corresponding to one nuclear disintegration per second Unit of radiation measurement corresponding to one nuclear disintegration per second Roentgen Roentgen A biological unit of radiation measurement used with X rays and gamma rays; the quantity of radiation that generates 2.1 X 10 9 ion pairs per 1 cm 3 of dry air or 1.8 X ion pairs per 1 g of tissue A biological unit of radiation measurement used with X rays and gamma rays; the quantity of radiation that generates 2.1 X 10 9 ion pairs per 1 cm 3 of dry air or 1.8 X ion pairs per 1 g of tissue Rad Rad A biological unit of radiation measurement corresponding to the transfer of 2.1 X cal of energy to 1 kg of tissue A biological unit of radiation measurement corresponding to the transfer of 2.1 X cal of energy to 1 kg of tissue

CONTINUED Gray Gray A biological unit of radiation measurement corresponding to the transfer of 1 J of energy to 1 kg of tissue A biological unit of radiation measurement corresponding to the transfer of 1 J of energy to 1 kg of tissue Rem Rem A biological unit of radiation measurement corresponding to the health effect produced by 1 roentgen of gamma or X-ray regardless of the type of radiation involved A biological unit of radiation measurement corresponding to the health effect produced by 1 roentgen of gamma or X-ray regardless of the type of radiation involved Geiger-Müller tube or counter Geiger-Müller tube or counter A radiation-detection device operating on the principle that ions form when radiation passes through a tube filled with low-pressure gas A radiation-detection device operating on the principle that ions form when radiation passes through a tube filled with low-pressure gas

MEDICAL USES OR RADIOISOTOPES Tracer Tracer A radioisotope used medically because its progress through the body or localization in specific organs can be followed. A radioisotope used medically because its progress through the body or localization in specific organs can be followed. Tracers should have short half-lives Tracers should have short half-lives Daughter produced from decaying isotope should be nontoxic Daughter produced from decaying isotope should be nontoxic Radioisotope should have a long enough half-life to be prepared and administered Radioisotope should have a long enough half-life to be prepared and administered Radiation given off by the isotope should be penetrating gamma rays, so they can be detected Radiation given off by the isotope should be penetrating gamma rays, so they can be detected Hot spot Hot spot Tissue in which a radioactive tracer concentrates Tissue in which a radioactive tracer concentrates Cold spot Cold spot Tissue form which a radioactive tracer is excluded or rejected Tissue form which a radioactive tracer is excluded or rejected

CONTINUED Radioisotopes administered internally for therapeutic use should ideally Radioisotopes administered internally for therapeutic use should ideally Emit less penetrating alpha or beta radiation to restrict the extent of damage Emit less penetrating alpha or beta radiation to restrict the extent of damage Half-life should be long enough to allow sufficient time for the desired therapy Half-life should be long enough to allow sufficient time for the desired therapy Decay products should be nontoxic and give off little or no radiation Decay products should be nontoxic and give off little or no radiation Target tissue should concentrate the radioisotope to restrict the radiation damage Target tissue should concentrate the radioisotope to restrict the radiation damage

NONMEDICAL USES Radioactive dating Radioactive dating A process for determining the age of artifacts and rocks, based on the amount and half-life of radioisotopes contained in the object A process for determining the age of artifacts and rocks, based on the amount and half-life of radioisotopes contained in the object Nuclear fission Nuclear fission A process in which large nuclei split into smaller, approximately equal-sized nuclei when bombarded by neutrons A process in which large nuclei split into smaller, approximately equal-sized nuclei when bombarded by neutrons Chain reaction Chain reaction A nuclear reaction in which the products of one reaction cause a repeat of the reaction to take place. In the case of uranium fission, neutrons from fission reactions cause other fission reaction to occur A nuclear reaction in which the products of one reaction cause a repeat of the reaction to take place. In the case of uranium fission, neutrons from fission reactions cause other fission reaction to occur

CONTINUED Branching chain reaction Branching chain reaction A reaction in which the products of one reaction cause more than one more reaction to occur A reaction in which the products of one reaction cause more than one more reaction to occur Critical reaction Critical reaction A constant-rate chain reaction A constant-rate chain reaction Supercritical reaction Supercritical reaction A branching chain reaction A branching chain reaction Critical mass Critical mass The minimum amount of fissionable material needed to sustain a critical chain reaction at a constant rate The minimum amount of fissionable material needed to sustain a critical chain reaction at a constant rate Supercritical mass Supercritical mass The minimum amount of fissionable material that must be present to cause a branching chain reaction to occur The minimum amount of fissionable material that must be present to cause a branching chain reaction to occur

LAST PAGE Breeding reactions Breeding reactions A nuclear reaction in which isotopes that will not undergo spontaneous fission are changed into isotopes that will A nuclear reaction in which isotopes that will not undergo spontaneous fission are changed into isotopes that will Thermonuclear reactions Thermonuclear reactions Nuclear fusion reactions that require a very high temperature to start them Nuclear fusion reactions that require a very high temperature to start them Nuclear fusion Nuclear fusion A process in which small nuclei combine or fuse to form larger nuclei A process in which small nuclei combine or fuse to form larger nuclei