Chem-Chap 10
Chemistry Chapter 10 Vocabulary
Terms
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- radioactive decay
- process where an unstable nucleus changes energy states and in the process emits radiation
- rad
- biological unit unit of radiation measurement corresponding to the transfer 1 x 10^-2 J or 2.4 x 10^-3 cal of energy to 1 kg of tissue
- radioactive nuclei
- nuclei that undergo spontaneous changes and emit energy in the form of radiation
- roentgen
- 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 1cm^3 of dry air or 1.8 x 10^12 ion pairs per 1 g of tissue
- moderators
- materials capable of slowing down neutrons that pass through them
- beta particle
- the particle that makes up beta rays; it is identical to an electron but is produced in the nucleus when a neutron is changed into a proton and an electron
- alpha particle
- particle that makes up alpha rays; it is identical to the helium nucleus and is composed of two protons and two neutrons
- linear accelerator
- particle accelerator that works b changing electrical polarities as charged particles cross gaps between segments of a long tube
- gray
- biological unit of radiation measurement corresponding to the transfer of 1 J of energy to 1 kg of tissue
- becquerel
- physical unit of radiation measurement corresponding to one nuclear disintegration per second
- breeder reaction
- nuclear reaction where isotopes that will not undergo spontaneous fission are changed into isotopes that will
- nuclear fission
- process where large nuclei split into smaller, app equal sized nuclei when bombarded by neutrons
- tracer
- radioisotope used medically because its progress through the body or localization in specific organs can be followed
- radioactive dating
- process for determining the age of artifacts and rocks based on the amount and half life of radioisotopes contained in the object
- transuranium elements
- synthetic slements with atomic numbers greater than that of uranium
- critical reaction
- constant rate chain reaction
- curie
- physical unit of radiation measurement corresponding to 3.7 x 10^10 nuclear disintegrations per second
- nuclear fusion
- process where small nuclei combine or fuse to form larger nuclei
- cold spot
- tissue from which a radioactive tracer is excluded or rejected
- physical unit of radiation
- radiation measurement unit indicating the activity of the source of the radiation; ex. number of nuclear decays per minute
- expanding or branching chain reaction
- reaction where the products of one reaction cause more than one more reaction to occur
- positron
- + charged electron
- supercritical mass
- minimum amount of fissionable material that must be present to cause a branching chain reaction to occur
- critical mass
- minimum amount of fissionable material needed to sustain a critical chain reaction at a constant rate
- biological unit of radiation
- radiation measurement unit indicating the damage caused by radiation in living tissue
- daughter nuclei
- the new nuclei produced when unstable nuclei undergo radioactive decay
- radical or free radical
- electron deficient particle that is very reactive
- chain reaction
- nuclear reaction where the products of one reaction causes a repeat of the reaction to take place; in the case of uranium fission, neutrons from fission reactions cause other fission reactions to occur
- scintillation counter
- radiation detection device operating on the principle that phosphors give off light when struck by radiation
- Geiger-Muller tube
- radiation detection device operating on the principle that ions form when radiation passes through a tube filled with low pressure gas
- hot spot
- tissue in which a radioactive tracer concentrates
- rem
- biological unit of radiation measurement corresponding to the health effect produced by 1 roentgen of gamme or X rays regardless of the type of radiation involved
- radioisotope
- an isotope of an element that emits nuclear radiation
- cyclotron
- cyclic particle accelerator that works by changing electrical polarities as charged particles cross a gap; the particles are kept moving in a spiral path by a strong magnetic field
- half life
- time required for one half the unstable nuclei in a sample to undergo radioactive decay
- inverse square law of radiation
- mathematical way of saying that the intensity of radiation is inversly proportional to the square of the distance from the source of the radiation
- acute radiation syndrome
- condition associated with and following short term exposure to intense radiation
- thermonuclear reactions
- nuclear fusion reactions that require a very high temperature to start
- supercritical reaction
- branching chain reaction
- electron capture
- mode of decay for some unstable nuclei where an electron from outside the nucleus is drawn into the nucleus, where it combbines with a proton to form a neutron
- gamma ray
- high energy ray that is like an X ray but with a higher energy