Chapter 9 Flashcards
Radioactivity
The process by which an unstable nucleus emits one or more particles or energy in the form of electromagnetic radiation
Nuclear decay
Emitting particles or releasing energy to become stable
Nuclear radiation
The particles that are released from the nucleus during radioactive decay
Alpha particle
A positively charged atom that is released in the disintegration of radioactive elements and that consists of two protons and two neutrons
Beta particle
A charged electron emitted during certain types of radioactive decay, such as beta decay
Neutron emission
type of radioactive decay of atoms containing excess neutrons, in which a neutron is simply ejected from the nucleus
Gamma ray
The high-energy photon emitted by a nucleus during fission and radioactive decay
Half-life
The time required for half of a sample of a radioactive substance to disintegrate by radioactive decay or by natural processes
Fission
The process by which a nucleus splits into two or more fragments and releases neutrons and energy
Nuclear chain reaction
A continuous series of nuclear fission reactions
Critical mass
The minimum mass of a fissionable isotope that provides the number of neutrons needed to sustain a chain reaction
Fusion
The process in which light nuclei combine at extremely high temperatures forming heavier nuclei and releasing energy
Strong nuclear force
force between protons and neutrons, subatomic particles that are collectively called nucleons
Background radiation
The nuclear radiation that arises naturally from cosmic rays and from radioactive isotopes in the soil and air
Rem
The quantity of ionizing radiation that does as much damage to human tissue as 1 roentgen of high-voltage X-rays does
