GCSE Topic 4: Atomic Structure

This set of vocabulary flashcards covers the history of the atom, subatomic particles, radioactive decay, and safety procedures related to radiation based on the GCSE Atomic Structure curriculum.

Plum pudding model

A model of the atom described as a pool of positive charge with negative particles floating around it.

Current model of the atom

A model where the center is a nucleus containing neutrons and protons, most of the atom is empty space, and electrons orbit at different energy levels.

Proton

A subatomic particle with a relative mass of $1$ that acts as the fingerprint of the element; carbon always has $6$ protons and adding one would change it to nitrogen with $7$.

Neutron

A subatomic particle with a relative mass of $1$ and no charge that is found in the nucleus.

Electron

A negative particle with a relative mass of basically $0$ that orbits the nucleus at specific energy levels.

Alpha Scattering Experiment

An experiment by Ernest Rutherford where alpha particles were fired at one cell thick gold foil, leading to the discovery of the nuclear model of the atom.

Isotope

An atom that has the same number of protons but a different number of neutrons, which changes the mass but not the charge.

Ion

An atom with the same number of protons but a different number of electrons, resulting in a change of charge but not mass.

Alpha radiation

Strongly ionizing radiation emitted from the nucleus that travels a few centimeters in air, is stopped by paper, and is used in smoke detectors.

Beta radiation

A fast moving electron released by the nucleus that is moderately ionizing, travels a few meters in air, is stopped by aluminum, and is used in material thickness testing.

Gamma radiation

An electromagnetic wave released by the nucleus that is weakly ionizing, travels a couple kilometers in air, and is stopped only by lead or meters of concrete.

Half life

The time taken for the number of radioactive nuclei to half.

Geiger Muller counter

The specific device used to measure radiation.

Activity

The rate at which a radioactive source decays, measured in becquerels.

Irradiation

The process of exposure to radiation, which can be reduced by keeping sources in lead lined boxes.

Contamination

When radioactive particles get onto objects or substances, often prevented by wearing PPE like gloves or special suits.

Becquerels

The unit of measurement for the activity of a radioactive source.