Overview of Nuclear Chemistry

Alpha Decay

Radioactive decay where an atom emits an alpha particle.

Alpha Particle

A helium nucleus emitted during alpha decay (2 protons and 2 neutrons).

Atomic Number

The number of protons in an atom's nucleus; defines the element.

Belt of Stability

The region on a neutron-proton plot representing stable nuclei.

Beta Decay

Radioactive decay where a neutron converts to a proton, emitting a beta particle.

Beta Particle

A high-energy electron emitted during beta decay.

Binding Energy per Nucleon

The binding energy of the nucleus divided by the number of nucleons it contains.

Chain reaction

A reaction where the product initiates further reactions.

Control rod

Neutron-absorbing rod used to control a nuclear reaction.

Critical Mass

The minimum amount of fissionable material needed to sustain a chain reaction.

Daughter nuclide

A nuclide produced by the radioactive decay of a parent nuclide.

Decay series

A series of radioactive nuclides produced by successive radioactive decay.

Electron Capture

A nucleus absorbs an inner electron, converting a proton to a neutron.

Gamma Emission

Release of a gamma ray from a nucleus; does not change the atom's identity.

Gamma Radiation

High-energy electromagnetic radiation emitted during radioactive decay.

Half-Life

The time required for half of a radioactive sample to decay.

Isotope

Atoms of the same element with different numbers of neutrons.

Mass Defect

The difference between the mass of an atom and the sum of its parts.

Mass Number

The total number of protons and neutrons in an atom's nucleus.

Moderator

Substance used to slow down neutrons in a nuclear reactor.

Neutron

A subatomic particle with no charge, found in the nucleus of an atom.

Nuclear Binding Energy

Energy released when a nucleus forms from nucleons, or needed to break it apart.

Nuclear Chain Reaction

A self-sustaining series of nuclear fissions caused by released neutrons.

Nuclear Fission

The splitting of a heavy nucleus into lighter nuclei, releasing energy.

Nuclear Fusion

The combining of light nuclei to form a heavier nucleus, releasing energy.

Nuclear Radiation

Particles or electromagnetic radiation emitted from the nucleus during radioactive decay.

Nuclear Reaction

A reaction that affects the nucleus of an atom.

Nuclear Shell Model

Nucleons exist in different energy levels, or shells, within the nucleus.

Nucleon

A collective term for protons and neutrons, the particles in the nucleus.

Nucleus

The dense, positively charged center of an atom, containing protons and neutrons.

Parent nuclide

The heaviest nuclide in a decay series

Positron

Particle with electron mass but positive charge, emitted during radioactive decay; symbol +1 (over) 0 B

Positron Emission

Radioactive decay where a proton converts to a neutron, emitting a positron.

Radioactive dating

Determines age of an object by measuring the amount of radioactive nuclides present.

Radioactive tracer

Radioactive atom incorporated into a substance to track its movement via radiation detection.

Radioactivity

The spontaneous emission of particles or energy from an unstable nucleus.

Radionuclide

A radioactive nuclide; an unstable atom that undergoes radioactive decay.

Shielding

Radiation-absorbing material used to reduce radiation exposure.

Transmutation

The change of one element into another through nuclear decay or bombardment.

Transuranium element

An element with an atomic number greater than 92.