Chapter 9 Nuclear Changes Flashcards
Radioactivity
The process by which an unstable nucleus emits one or more particles or energy in the form of electromagnetic radiation.
Nuclear Decay
Unstable nuclei emit particles or release energy to become stable.
Nuclear Radiation
The particles that are released from the nucleus during radioactive decay.
Alpha Particle
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
Neutrons emitted from an unstable nuclei, but since they have no charge, they do not ionize matter.
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
Causes protons and neutrons in the nucleus to attract each other. Stronger than the electric repulsion between protons.
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.
