Chapter 21: Radioactivity and Nuclear Chemistry Flashcards
alpha decay
The form of radioactive decay that occurs when an unstable nucleus emits a particle composed of two protons and two neutrons.
alpha particle
A low-energy particle released during alpha decay; equivalent to a He-4 nucleus.
beta decay
The form of radioactive decay that occurs when an unstable nucleus emits an electron.
beta particle
A medium-energy particle released during beta decay; equivalent to an electron.
biological effectiveness factor (RBE)
A correction factor multiplied by the dose of radiation exposure in rad to obtain the dose in rem.
chain reaction
A series of reactions in which previous reactions cause future ones; in a fission bomb, neutrons produced by the fission of one uranium nucleus induce fission in other uranium nuclei.
electron capture
The form of radioactive decay that occurs when a nucleus assimilates an electron from an inner orbital.
critical mass
The necessary amount of a radioactive isotope required to produce a self-sustaining fission reaction.
cyclotron
A particle accelerator in which a charged particle is accelerated in an evacuated ring-shaped tube by an alternating voltage applied to each semicircular half of the ring.
film-badge dosimeter
A device for monitoring exposure to radiation consisting of photographic film held in a small case that is pinned to clothing.
gamma ray
The form of electromagnetic radiation with the shortest wavelength and highest energy.
Geiger-Muller counter
A device used to detect radioactivity that uses argon atoms that become ionized in the presense of energetic particles to produce an electrical signal.
ionizing power
The ability of radiation to ionize molecules and atoms.
linear accelerator
A particle accelerator in which a charged particle is accelerated in an evacuated tube by a potential difference between the ends of the tube or by alternating charges in sections of the tube.
magic numbers
Certain numbers of nucleons (N or Z = 2, 8, 20, 28, 50, 82, and N = 126) that confer unique stability.
mass defect
The difference in mass between the nucleus of an atom and the sum of the separated particles that make up that nucleus.
nuclear equation
An equation that represents nuclear processes such as radioactivity.
nuclear binding energy
The amount of energy required to break apart the nucleus into its component nucleons.
nuclear fission
The splitting of the nucleus of an atom, which results in a tremendous release of energy.
nuclear fusion
The combination of two light nuclei to form a heavier one.
gamma ray emission
The form of radioactive decay that occurs when an unstable nucleus emits extremely high-frequencey electromagnetic radiation.
nucleons
One of the particles that compose the nucleus, which are protons and neutrons.
nuclide
A particular isotope of an atom.
penetrating power
The ability of radiation to penetrate matter.
phosphorescence
The long-lived emission of light that sometimes follows the absorption of light by certain atoms and molecules.
positron
The particle released in positron emission; equal in mass to an electron but opposite in charge.
positron emission
The form of radioactive decay that occurs when an unstable nucleus emits a positron.
positron emission tomography (PET)
A specialized imaging technique that employs positron-emitting nuclides, such as fluorine-18, as a radiotracer.
radioactive
Describes the state of unstable atoms that emit subatomic particles or high-energy electromagnetic radiation.
radioactivity
The emission of subatomic particles or high-energy electromagnetic radiation by the unstable nuclei of certain atoms.
radiocarbon dating
A form of radiometric dating based on the C-14 isotope.
radiometric dating
A technique used to estimate the age of rocks, fossils, or artifacts that depends on the presence of radioactive isotopes and the predictable decay of those isotopes over time.
radiotracer
A radiactive nuclide attached to a compound or introduced into a mixture in order to track the movement of the compound or mixture within the body.
rem
A unit of radiation exposure that stands for roentgen equivalent man, where a roentgen is defined as the amount of radiation that produces 2.58 x 10-4C of charge per kg of air.
scintillation counter
A device for the detection of radiactivity that includes a material that emits ultraviolet or visible light in response to excitation by energetic particles.
strong force
Of the four fundamental forces of physics, the one that is the strongest but acts over the shortest distance; the strong force is responsible for holding the protons and neutrons together in the nucleus of an atom.
transmutation
The transformation of one element into another as a result of nuclear reactions.
