Particles and Unstable Nuclei

Vocabulary flashcards covering atomic structure, specific charge, nuclear decay, strong nuclear force, photons, and antiparticles based on the lecture material.

Nucleon

A proton or a neutron located inside the nucleus of an atom.

Proton Number ($Z$)

The number of protons in the nucleus of an atom, also known as the atomic number, which uniquely defines the chemical element.

Nucleon Number ($A$)

The total number of protons and neutrons in the nucleus of an atom, also known as the mass number.

Isotopes

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

Specific Charge

The ratio of a particle's charge to its mass, calculated as charge divided by mass and given in $\text{C}\text{kg}^{-1}$.

Fundamental Particle

A particle that cannot be broken down into anything smaller.

Carbon-14 Dating

A technique used to calculate the approximate age of archaeological finds from dead organic matter by measuring the percentage of radioactive carbon-14 remaining.

Strong Nuclear Force

An attractive force that binds nucleons together in the nucleus and overcomes the repulsive electrostatic force between protons.

Distance Dependence of the Strong Nuclear Force

The force between nucleons that is repulsive at separations below about $0.5\,\text{fm}$, becomes attractive past $0.5\,\text{fm}$, reaches a maximum value, and falls rapidly towards zero after about $3\,\text{fm}$.

Alpha Emission

The release of an alpha particle from a large, unstable nucleus, causing the proton number to decrease by $2$ and the nucleon number to decrease by $4$.

Cloud Chamber

A detector used to observe the visible tracks left by alpha particles.

Geiger Counter

A device used to measure the amount of ionising radiation produced by a radioactive source.

Beta-minus Decay

A process in neutron-rich nuclei where a neutron changes into a proton, emitting an electron (beta particle) and an antineutrino, increasing the proton number by $1$ while the nucleon number stays the same.

Antineutrino

A tiny neutral particle with zero or almost zero mass released during beta decay to carry away missing energy and momentum.

Photon

A packet of electromagnetic energy whose value depends on frequency according to $E = hf$.

Planck Constant ($h$)

A fundamental physical constant equal to $6.63 \times 10^{-34}\,\text{J}\,\text{s}$.

Antiparticle

A particle corresponding to a matter particle that has the exact same mass and rest energy, but opposite charge.

Rest Energy

The energy equivalent of a particle's mass, measured in \text{MeV}.

Pair Production

The process where high-energy particle interactions convert energy into equal amounts of matter and antimatter.