Topic 7 - Atomic, Nuclear, and Particle Physics

Definitions for Topic 7 - Atomic, Nuclear, and Particle Physics: 7.1 - Discrete energy and radioactivity 7.2 - Nuclear reactions 7.3 - The structure of matter

Energy level

Electrons can be in different orbits around the nucleus, these different orbits are called energy levels

Quantised

Radioactive decay

The process by which an unstable atomic nucleus loses energy through radiation, the nucleus becomes more stable

Random and spontaneous

(Atomic) nucleus

The small, dense region at the center of an atom

Nucleon

A component of an atomic nucleus, so either a portion or a neutron

Nuclide

A species of an atom with a specific number of protons and neutrons in the nucleus

Isotope

Same element with the same number of protons, but a different number of neutrons

Background count

Naturally occurring radioactive decay is measured by a counter

Half-life

The time it takes for half of the parent nuclides in a sample to decay

Unified atomic mass unit

One-twelfth of the rest mass of an unbound, neutral carbon-12 atom in its nuclear and electronic ground state

1.661*10^-27 kg

Nuclear binding energy

The energy required to completely separate the nucleons of a nucleus

Quark confinement

That quarks do not exist on their own.

Always found in groups, within hadrons (two or three quarks)

Three quarks -> baryon; a quark and an antiquark -> meson

Strong nuclear force

Higgs boson

Predicted before it was observed, observed in 2012

Part of the Standard Model

Other particles gain mass by interacting with the Higgs field

No charge