chapter 28 vocabulary Flashcards
(22 cards)
alpha particle
a positively charged particle emitted from certain radioactive nuclei; it consists of two protons and two neutrons and is identical to the nucleus of a helium atom
alpha radiation
alpha particles emitted from a radioactive source
band of stability
the location of stable nuclei on a neutron vs. proton plot
beta particle
a fast- moving electron emitted from certain radioactive nuclei: it is formed when a neutron decomposes into a proton and an electron
beta radiation
fast moving electrons (beta particles) emitted from a radioactive source
film badge
a small radiation detector form by persons who work near radiation sources ; it consists of several layers of photographic film covered with black light proof paper encased in a plastic of metal holder
fission
the splitting of a nucleus into smaller fragments, accompanied by the release of neutrons and a large amount of energy
fusion
a reaction in which two light nuclei combine to produce a nucleus of heaver mass, accompanied by the release of a large amount of energy
gamma radiation
high energy electromagnetic radiation emitted by certain radioactive nuclei; gamma rays have no mass or electrical charge
geiger counter
a gas filled metal tire used to detect the presence of beta radiation
half life
the time required for one half of the atoms of a radioisotope to emit radiation and decay to products
ionizing radiation
radiation with enough energy to produce ions by knocking electrons off some atoms of a bombarded substance
neutron absorption
a process used in a nuclear reactor to slow the chain reaction by decreasing the number of moving neutrons; this is done with control rods made of a material such as cadmium that absorbs neutrons
neutron moderation
a process used in a nuclear reactor to slow the neutrons so they can be captured by the reactor fuel to continue the chain reaction; water and carbon are good moderators
positron
a particle that has the same mass as an electron but that has a positive charge
radiation
the penetrating rays and particles emitted by a radioactive source
radioactive decay
the spontaneous emission of radiation by an unstable nucleus; the rate of decay is unaffected by temperature, pressure of catalysts
radioactivity
the process by which unstable atomic nuclei achieve stability
radioisotope
an isotope that has an unstable nucleus and undergoes radioactive decay
scintillation counter
a device uses a surface coated with a phosphor to detect radiation; ionizing radiation striking the phosphor surface produces bright flashes of light (scintillations)
transmutation
natural or artificial conversion of an atom of one element into an atom of another element by the emission of radiation from an unstable nucleus
transuranium elements
an element in the periodic table with an atomic number that is greater than 92
