Band of stability
the stable nuclei cluster over a range of neutron-proton ratios
Binding energy per nucleon
the binding energy of the nucleus divided by the number of nucleons it contains
Magic numbers
the numbers of nucleons that represent completed nuclear energy levels- 2, 8, 20, 28, 50, 82, and 126
Mass defect
the difference between the mass of an atom and the sum of the masses of its protons, neutrons, and electrons
Nuclear binding energy
the energy released when a nucleus is formed from nucleons
Nuclear Reaction
a reaction that affects the nucleus of an atom
Nuclear shell model
nucleon exists in different energy levels, or shells, in the nucleus
Nucleon
a proton or neutron
Nuclide
the general term for any isotope of any element; another term for an atom that is identified by the number of protons and neutrons in its nucleus
Transmutation
a change in the identity of the nucleus as a result of a change in the number of its protons
Alpha particle
is two protons and two neutrons bound together and is emitted from the nucleus during some kinds of radioactive decay.
Artificial transmutation
bombardment of stable nuclei with charged and uncharged particles
Beta particle
an electron emitted from the nucleus during some kinds of radioactive decay
Daughter nuclides
a nuclide produced by the decay of a parent nuclide
Decay series
a series of radioactive nuclides produced by successive radioactive decay until a stable nuclide is reached
Electron capture
the process in which an inner orbital electron is captured by the nucleus of its own atom
Gamma ray
a high-energy electromagnetic wave emitted from a nucleus as it changes from an excited state to a ground energy state
Half-life
the time required for half the atoms of a radioactive nuclide to decay
Nuclear radiation
the particles or electromagnetic radiation emitted from the nucleus during radioactive decay
Parent nuclide
the heaviest nuclide of each decay series
Positron
a particle that has the same mass as an electron but that has a positive charge, and is emitted from the nucleus during some kinds of radioactive decay
Radioactive decay
the spontaneous disintegration of a nucleus into a slightly lighter and more stable nucleus, accompanied by emission of particles, electromagnetic radiation, or both
Radioactive Nuclide
an unstable nucleus that undergoes radioactive decay
Transuranium element
an element with more than 92 protons in its nucleus
Film badge
a device that uses exposure of film to measure the approximate radiation exposure of people working with radiation
Geiger-M�ller counter
an instrument that detects radiation by counting electric pulses carried by gas ionized by radiation
Nuclear Waste
radioactive products of fission and fusion reactions
Radioactive dating
the process by which the approximate age of an object is determined based on the amount of certain radioactive nuclides present
Radioactive tracer
a radioactive atom that is incorporated into a substance so that movement of the substance can be followed by a radiation detector
Rem
the quantity of ionizing radiation that does as much damage to human tissue as is done by 1 roentgen of high-voltage X rays
Roentgen
a unit used to measure nuclear radiation; equal to the amount of radiation that produces 2 x 10^9 ion pairs when it passes through 1 cm^3 of dry air
Scintillation counter
an instrument that converts scintillating light to an electric signal for detecting radiation
Chain reaction
a reaction in which the material that starts the reaction is also one of the products and can start another reaction
Control rod
a neutron-absorbing rod that helps control a nuclear reaction by limiting the number of free neutrons
Critical mass
the minimum amount of nuclide that provides the number of neutrons needed to sustain a chain reaction
Moderator
a material used to slow down the fast neutrons produced by fission
Nuclear fission
a process in which a very heavy nucleus splits into more stable nuclei of intermediate mass
Nuclear fusion
the combining of light-mass nuclei to form a heavier, more stable nucleus
Nuclear power plant
a facility that uses heat from nuclear reactors to produce electrical energy
Nuclear Reactor
a device that uses controlled-fission chain reactions to produce energy or radioactive nuclides
Shielding
radiation-absorbing material that is used to decrease radiation exposure from nuclear reactors, especially gamma rays