Chapter 5 Flashcards
Alpha particle
A subatomic particle consisting of the combina- tion of two protons and two neutrons ejected by a radio- active nucleus. The composition of an alpha particle is the same as that of the nucleus of a helium atom.
Beta particle
An electron emitted during the radioactive decay of a radioactive nucleus.
Carbon-14 dating
The process of estimating the age of once- living material by measuring the amount of radioactive carbon-14 present in the material.
Chain reaction
A self-sustaining reaction in which the prod- ucts of one reaction event initiate further reaction events.
Critical mass
The minimum mass of fissionable material needed for a sustainable chain reaction.
Gamma rays
High-frequency electromagnetic radiation emitted by radioactive nuclei.
Half-life
The time required for half the atoms in a sample of a radioactive isotope to decay.
Nuclear fission
The splitting of the atomic nucleus into two smaller halves.
Nuclear fusion
The combining of nuclei of light atoms to form heavier nuclei.
Radioactive
Material containing nuclei that are unstable because of a less than optimal balance in the number of neutrons and protons.
Radioactivity
The high-energy particles and electromagnetic radiation emitted by a radioactive substance.
Rem
A unit for measuring the ability of radiation to harm living tissue.
Strong nuclear force
The attractive force between all nucleons - effective only at very short distances.
Thermonuclear fusion
Nuclear fusion brought about by high temperatures.
Transmutation
The changing of an atomic nucleus of one element into an atomic nucleus of another element through a decrease or increase in the number of protons.
