Atomic chemistry

Proton

A positively charged subatomic particle with a relative mass of 1, located in the nucleus of an atom.

Neutron

A subatomic particle with a relative mass of 1, located inside the nucleus.

Electron

A negatively charged particle with a relative mass of 1/1836, located on the outside of the nucleus in shells or electron cloud.

Isotope

Atoms of the same element with the same number of protons and electrons but different numbers of neutrons, leading to different atomic masses.

Atomic Number

The number of protons in an element.

Atomic Mass

The total count of protons and neutrons in an atom.

Stable Atom

An atom with equal numbers of protons and electrons, resulting in a neutral charge.

Ion

An atom that has gained or lost electrons, resulting in a charge.

Radioactive Decay

The random spontaneous nuclear change that makes the nucleus more stable and releases radiation.

Ionising Radiation

Energy released during radioactive decay causing electron removal from surrounding atoms, potentially leading to cell and DNA damage.

Half Life

The time taken for half the radioactive nuclei in a sample to decay.

Half Life Equation

Remaining amount = initial amount × (½)^n, where n = time divided by half life.

Alpha Decay

A type of radioactive decay where the mass number decreases by 4 and the atomic number decreases by 2.

Beta Decay

A type of radioactive decay where the mass number stays the same but the atomic number increases by 1.

Gamma Decay

A type of radioactive decay where both mass number and atomic number remain unchanged.