Particles key terms

Proton

A positively charged subatomic particle found in the nucleus of an atom, contributing to the atomic number and mass.

Neutron

A neutral subatomic particle located in the nucleus of an atom, contributing to the atomic mass but not the charge.

Proton number

The number of protons in the nucleus of an atom, which determines the element's identity.

Neutron number

The number of neutrons in the nucleus of an atom, which contributes to the atomic mass and can vary in isotopes.

isotope

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

neutron number

The number of neutrons in an atomic nucleus, which contributes to the mass number of the atom.

specific charge

The ratio of the charge of a particle to its mass, typically expressed in coulombs per kilogram (C/kg).

mass-to-charge ratio

The ratio of the mass of a particle to its charge, often used in contexts such as mass spectrometry, expressed in kilograms per coulomb (kg/C).

unstable nuclei

Nuclei that have an imbalance in the number of protons and neutrons, leading to radioactive decay.

radioactive decay

The process by which unstable nuclei lose energy by emitting radiation, resulting in the transformation into more stable nuclei.

Alpha radiation

A type of radiation consisting of helium nuclei, which have a positive charge and are relatively heavy, resulting in low penetration ability.

Beta radiation

A type of radiation consisting of high-energy, high-speed electrons or positrons emitted from a nucleus, which have a negative charge and moderate penetration ability.

radioactive decay

The process by which an unstable atomic nucleus loses energy by emitting radiation, resulting in the transformation of the nucleus into a different element or isotope.

random nuclear process

A process in which the exact time of decay of a radioactive nucleus cannot be predicted, leading to a statistical distribution of decay events over time.

activity

The rate at which a sample of radioactive material decays, measured in becquerels (Bq).

background radiation

The ionizing radiation present in the environment from natural and artificial sources, typically measured in microsieverts (µSv).

particle-antiparticle pair

A pair of particles where one is the antiparticle of the other, having opposite charge and quantum numbers.

opposite properties

Characteristics that are inversely related, such as charge, where a particle has a positive charge and its antiparticle has a negative charge.

annihilation

The process in which a particle and its corresponding antiparticle collide and convert their mass into energy, typically in the form of photons.

pair production

The creation of a particle-antiparticle pair from a photon when it has sufficient energy, as described by the equation E = hf.

E = hf

This formula relates the energy (E) of a photon to its frequency (f), where h is Planck's constant.

mass-energy equivalence

This principle states that mass can be converted into energy and vice versa, expressed by the equation E = mc².

conservation of charge

The principle that the total electric charge in an isolated system remains constant over time.

momentum conservation

The principle stating that the total momentum of a closed system is conserved in the absence of external forces.

exchange particle

A particle that mediates interactions between other particles, such as photons for electromagnetic interactions.

W boson

A type of exchange particle responsible for mediating weak nuclear interactions, involved in processes like beta decay.

photon

A quantum of electromagnetic radiation, which acts as the exchange particle for electromagnetic interactions.

exchange particle

A particle that mediates the interactions between other particles, such as the photon for electromagnetic forces.

W boson

A fundamental particle that mediates the weak nuclear force, responsible for processes like beta decay.

exchange particle

A particle that is exchanged between other particles during an interaction, facilitating the force between them.