Atomic Theory & Radiation Study Guide

Vocabulary flashcards covering atomic theory, radioactive decay, nuclear reactions (fission and fusion), and fundamental particles based on the provided study guide notes.

Atomic Mass (Mass #)

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

Average atomic mass

A weighted average of the atomic masses of an element's naturally occurring isotopes.

Alpha decay particle

A helium nucleus (He) consisting of two protons and two neutrons.

Beta decay particle

An electron (e) emitted from the nucleus.

Gamma ray

A high-energy photon (by) that is the most penetrating form of radiation, possessing no mass and pure energy.

Positron

An anti-electron (+ie) with the same mass as an electron but an opposite positive charge.

Electron capture

A nuclear decay process where an inner orbital electron is absorbed into the nucleus, combining with a proton to form a neutron.

Half-life

The time required for one-half of the radioactive nuclei in a radio-isotope sample to decay.

Fusion

A nuclear reaction in which two or more atomic nuclei combine to form a single, heavier nucleus.

Fission

A nuclear reaction in which a heavy nucleus splits into smaller fragments, often releasing a large amount of energy.

Moderation (in nuclear power plants)

A process that slows down the speed of neutrons to sustain a controlled nuclear fission reaction.

Nuclear absorption (in nuclear power plants)

A process that decreases neutron flux, controlling the rate of nuclear fission.

Neutron (relative mass)

1 atomic mass unit (amu).

Proton (relative mass)

1 atomic mass unit (amu).

Electron (relative mass)

Approximately 1/1840 of an atomic mass unit (amu).

Nuclear weapon

A device that utilizes an uncontrolled nuclear fission chain reaction (and sometimes uncontrolled fusion) to release an immense amount of energy.

Controlled fission

The process of managing nuclear fission reactions to produce useful energy, typically in nuclear power plants.

Antiproton

The antiparticle of a proton, possessing a negative charge.

Positron (anti-electron)

The antiparticle of an electron, possessing a positive charge.

Quarks

Elementary particles that combine to form composite particles called hadrons, such as protons and neutrons.