Topic 4 Atomic Structure - AQA Physics GCSE

Atomic Structure

The arrangement of protons, neutrons, and electrons in an atom.

Subatomic Particle

A particle that is smaller than an atom, such as protons, neutrons, and electrons.

Proton

A subatomic particle with a positive charge and a relative mass of 1.

Neutron

A subatomic particle with no charge (neutral) and a relative mass of 1.

Electron

A subatomic particle with a negative charge and a very small relative mass of 0.0005.

Isotopes

Atoms of the same element that have the same number of protons but different numbers of neutrons.

Electron Arrangement

The distribution of electrons in different energy levels around the nucleus of an atom.

EM Radiation

Electromagnetic radiation, such as light or radio waves.

Nucleus

The positively charged central part of an atom, containing protons and neutrons.

Radioactive Decay

The process in which an unstable atomic nucleus emits radiation and transforms into a more stable nucleus.

Alpha Decay

A type of radioactive decay in which an alpha particle (two protons and two neutrons) is emitted from the nucleus.

Beta Decay

A type of radioactive decay in which a beta particle (an electron) is emitted from the nucleus.

Gamma Decay

A type of radioactive decay in which a gamma ray (high-energy electromagnetic radiation) is emitted from the nucleus.

Half-Life

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

Americium

A radioactive element with a half-life of 432 years, commonly used in smoke alarms.

Net Decline

The ratio of the decrease in radioactive nuclei after a certain number of half-lives.

Contamination

The presence of unwanted radioactive atoms on other materials, which can release radiation.

Irradiation

The exposure of an object to nuclear radiation without making it radioactive.

Peer Review

The process of having scientific reports reviewed by experts in the field before publication.

Background Radiation

Weak radiation from natural or external sources, such as cosmic rays or nuclear fallout.

Radiation Dose

The measurement of radiation exposure, typically measured in Sieverts (Sv).