Particles in the Nucleus

Chapter 8 Pearson Key Terms

Standard Model

A system of categorising subatomic particles including quarks and leptons, which can be used to describe the vast array of particles observed in particle accelerator collisions.

Fermions

Particle that include quarks and leptons, and the particles that are composed of odd numbers of quarks.

Quarks

Fundamental particles that only interact via the strong nuclear force. There are six types of quark: up, down, top, bottom, charmed, and strange. Each quark has an antimatter particle.

Leptons

A fundamental particle that does not interact with the strong nuclear force. There are six leptons: electron, electron neutrino, muon, muon neutrino, tau, and tau neutrino. Each of these particles has an antimatter particle.

Particle Accelerators

A device used to accelerate charged particles using electric and magnetic felds. Particle physicists use these to collide particles in their search for new matter.

Gauge Bosons

Force mediating particle used in the Standard Model that is equivalent to forces that act at a distance via felds. Four types: gluon (strong nuclear), W (weak nuclear), Z (weak nuclear), and the photon (electromagnetic).

Photon

A wave-like particle that carries electromagnetic energy. In the Standard Model it is a particle that mediates the electromagnetic force.

Gluon

Force mediating particle used in the Standard Model that is equivalent to the strong nuclear force.

Antiparticle

A particle that has equivalent mass, but opposite charge, and opposite quantum properties of normal matter.

Quantum Number

According to the quantum theory, particles have properties referred to as quantum numbers, one of which is ‘spin’.

Hadrons

Particle comprised of quarks bound together by gluons. Hadrons may have three quarks, or a quark and an antiquark.

Baryons

Particle comprised of three quarks bound together by gluons. Protons and neutrons are baryons.

Mesons

Particle comprised of a quark and an antiquark, bound together by gluons. Pions and kaons are examples of mesons.

Electron Neutrinos

A neutral subatomic lepton particle that interacts very weakly with other matter. It is associated with the electron and is the counterpart to the antielectron neutrino.

Electromagnetic Force

The attractive or repulsive force experienced by electric or magnetic objects due to other electric or magnetic objects.

Radioactive

Something that spontaneously emits radiation in the form of alpha particles, beta-plus or beta-minus particles, and/or gamma rays.

Radiation

Rays or particles that carry energy. Also, the process by which energy is emitted by an object or system, transmitted through an intervening medium or space, and absorbed by another object or system.

Nucleons

A particle located in the nucleus of an atom.

Mass Number

The number of nucleons (protons and neutrons) in a nucleus.

Atomic Number

The number of protons in a nucleus.

Isotopes

Atoms with the same number of protons but with different numbers of neutrons.

Nuclide

The range of atomic nuclei associated with a particular atom, which is defned by its atomic number, and the various isotopes of that atom as identifed by the mass number.

Spontaneous Transmutation

The changing of one element into another in a natural process involving radioactive decay.

Radioisotope

An isotope of a chemical element that emits radioactivity due to having an unstable combination of neutrons and protons in the nucleus.

Artificial Transmutation

The changing of one element or isotope into another. This happens during radioactive decay and during neutron bombardment in a nuclear reactor.

Electrostatic Force

A force that acts between charged particles and can act over relatively large distances.

Strong Nuclear Force

A short-range but powerful force of attraction that acts between all the nucleons in the nucleus. The strong nuclear force acts on quarks and binds them together in hadrons. It also acts to bind protons and neutrons together within atomic nuclei.