Chapter Two: Modes of Radioactive Decay

A process where an unstable nucleus transforms into a more stable one by emitting particles, photons, or both, releasing energy.

The unstable nucleus undergoing radioactive decay.

The more stable nucleus formed after radioactive decay.

Radioactive decay where the time of decay cannot be predicted and is not influenced by external factors.

The total energy released during radioactive decay, mostly converted into kinetic energy of emitted particles or photons.

A radioactive isotope of a chemical element.

The unique mode of radioactive decay, transition energy, and average lifetime of a radionuclide before its decay.

The property of a nucleus that causes it to undergo radioactive decay.

Pair of high-energy photons emitted when a positron and electron meet and are mutually destroyed.

Radioactive decay where a proton turns into a neutron, emitting a positron and a neutrino.

Minimum energy required for β+ decay. Part of the rest mass energy of the electron-positron pair

Daughter nucleus decay from a metastable state to ground state by gamma emission

Antiparticle of an electron having the same mass but opposite charge.

Type of radioactive decay where a neutron transforms into a proton, emitting a beta particle and an antineutrino, changing the atomic number.

Radioactive decay where the mass number (A) of the parent and daughter nuclei remains the same.

Gamma-ray emission from an excited nucleus.

The nucleus that results after radioactive decay.

Graphical representation of a radioactive decay process showing energy changes and the relationship between parent and daughter nuclei.

Total energy released during the decay process

Total energy released during radioactive decay, shared between decay products.

Energetic electron emitted during β decay, originating from within the nucleus.

Decay process involving β emission followed by γ-ray emission if excited daughter nucleus is formed.

β particles can only penetrate thin materials, making detection from inside the body challenging.

A small, neutral particle released during β decay, carrying away some of the energy released.

Alpha particles travel only a few centimeters and are easily stopped by a thin layer of material like dead skin.

Beta particles (high-speed electrons) can travel several centimeters in living tissue, losing energy gradually.

Gamma and X-rays can penetrate significantly more deeply into tissue than alpha or beta particles, requiring substantial shielding (like concrete or lead).

A chart displaying stable and radioactive nuclides, organized by atomic number and neutron number.

Nuclides with same atomic number (isotopes) and same neutron number (isotones) are located on, respectively, horizontal rows and vertical columns in the Chart of Nuclides.

Nuclear decay where the nucleus transfers energy to an orbital electron, ejecting it instead of emitting a gamma ray.

Electron capture decay, where an electron from the inner shell of an atom is captured by the nucleus and combines with a proton to form a neutron, changing the atomic number.

Electron capture decay followed by gamma-ray emission from an excited daughter nucleus.

Electron ejected during internal conversion, carrying energy from the nucleus.

A proton in the nucleus transforms into a neutron, emitting a positron and a neutrino.

Nuclear decay where an orbital electron combines with a proton to form a neutron, releasing a neutrino.

Electron capture from the K-shell.

A helium nucleus (2 protons and 2 neutrons) emitted during radioactive decay.

Radioactive decay where the mass number (A) remains the same, but the atomic number changes.

High-energy electromagnetic radiation emitted from an excited nucleus.

Diagram showing energy levels and paths of decay process for a radionuclide.

An excited state of a nucleus with a relatively long lifetime before decaying, compared to a shorter-lived excited state.

Radioactive decay where the mass number remains the same, only atomic number changes.

Nuclear decay involving emission of a gamma ray, a high-energy photon.

A state of an atom or nucleus where its electrons are at a higher energy level than in its ground state.

A type of radioactive decay in which an inner atomic orbital electron is absorbed by the nucleus.