Chapter 9 Flashcards
Radioactivity
The process when an unstable nucleus emits one or more particles or energy in the form of electromagnetic radiation.
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.
Neutron emission
Consists of matter that is emitted from an unstable nucleus.
Gamma ray
A 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 process.
Fission
When 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
When light nuclei combine at extremely high temperature, forming heavier nuclei and releasing energy.
Strong nuclear force
Causes protons and neutrons in the nucleus to tract each other.
Background radiation
The nuclear radiation that arises naturally from cosmic rays and from radioactive isotopes in the soil and air.
Rem
Quantity of ionized radiation
Radioactive tracer
Radioactive material that is added to a substance so that its distribution can be found later
