Physical Science - Radioactive Decay & Nuclear Reactions Save

Alpha Particle

A particle consisting of two protons and two neutrons that is emitted from a decaying atomic nucleus.

Atomic Number

The number of protons in an atom's nucleus.

Average Atomic Mass

Weighted-average of an element's isotopes according to their natural abundance.

Beta Particle

A high-energy electron that is emitted when a neutron decays into a proton.

Chain Reaction

A series of fission reactions caused by the release of additional neutrons in every step.

Critical Mass

The minimum mass of fissionable material in a nuclear reactor or nuclear bomb that will sustain a chain reaction.

Fission

The process of splitting an atomic nucleus into two or more nuclei with smaller masses, releasing large amounts of energy.

Fusion

A reaction in which two or more atomic nuclei form a nucleus with a larger mass, releasing large amounts of energy.

Half-life

The amount of time it takes for half the nuclei in a sample of a radioactive isotope to decay.

Isotope

An atom of an element that has a specific number of neutrons.

Mass Number

Sum of the number of protons and neutrons in an atom's nucleus.

Nucleon

The principal building block of the nucleus; a neutron or a proton.

Radiation

The transfer of energy by electromagnetic waves.

Radioactive Element

An element, such as radium, whose nucleus breaks down and emits particles and energy.

Radioactivity

A process that occurs when a nucleus decay and emits matter and energy.

Strong Force

Attractive force that acts between protons and neutrons in an atomic nucleus.

Thermonuclear Fusion

Nuclear fusion brought about by extremely high temperatures.

Tracer

A radioactive isotope, such as iodine-131, that can be dejected by the radiation it emits after it is absorbed by a living organism.

Transmutation

A process of changing one element to another through radioactive decay.