Radioactivity and Nuclear Chemistry

This set covers the fundamental concepts of radioactivity, types of nuclear decay, identification of isotopes and nuclides, stability factors, kinetics of decay, dating techniques, nuclear energetics (fission and fusion), detection methods, and biological/medical applications.

Radioactivity

The emission of subatomic particles or high-energy electromagnetic radiation by the nuclei of certain atoms.

Phosphorescence

The long-lived emission of light by atoms or molecules that sometimes occurs after they absorb light.

Uranic rays

The name Antoine-Henri Becquerel initially used for rays emitted from minerals containing uranium, before the term radioactivity was coined.

Atomic number (Z)

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

Mass number (A)

The sum of the number of protons and neutrons in an atom's nucleus.

Nuclide

The term used for a nucleus when discussing nuclear properties and specific isotopes.

Alpha particle

A particle composed of two protons and two neutrons, equivalent to a helium-4 nucleus, symbolized as ${}^4_2 ext{He}$ or ${}^4_2 ext{alpha}$.

Beta particle

An electron-like particle emitted from the nucleus with a charge of $-1$ and negligible mass, symbolized as ${}^0_{-1}e$ or {}^0_{-1}eta.

Gamma rays

A form of high-energy electromagnetic radiation (photons) with no mass and no charge that often accompanies other types of decay.

Positron

The antiparticle of the electron, having a charge of $+1$ and negligible mass, symbolized as ${}^0_{+1}e$ or {}^0_{+1}eta.

Electron capture

A nuclear process where an inner orbital electron is pulled into the nucleus, combining with a proton to form a neutron.

Ionizing Power

The ability of radiation to ionize other molecules and atoms; it is highest in alpha radiation.

Penetrating Power

The ability of radiation to pass through matter; gamma rays have the highest whereas alpha particles have the lowest.

Strong force

A very strong attractive force that acts only over very short distances to hold protons and neutrons together in the nucleus.

Nucleons

The collective term for the protons and neutrons found within a nucleus.

Magic numbers

Specific numbers of nucleons that lead to unique nuclear stability: $N$ or $Z = 2, 8, 20, 28, 50, 82$, or $N = 126$.

Decay series

A sequence of radioactive decays where one radioactive nuclide transforms into another until a stable nuclide is reached.

Thermoluminescent dosimeters

Devices containing salt crystals that emit light proportional to radiation exposure when heated.

Geiger-Müller counter

An instrument that detects radiation by counting electrons produced when argon gas atoms are ionized by radioactive rays.

Scintillation counter

A device that counts radioactivity by measuring flashes of light produced when rays strike certain chemicals.

Half-life

The constant time interval required for one-half of the radioactive nuclei in a sample to decay.

Radiocarbon dating

A method for estimating the age of once-living objects by comparing the ratio of $C-14$ to $C-12$; effective for objects up to $50,000$ years old.

Nuclear fission

The splitting of a large nucleus into two smaller nuclides, typically initiated by a reaction with a neutron.

Nuclear fusion

The combining of light nuclei to form a heavier nucleus, releasing more energy per gram than fission.

Critical mass

The minimum amount of a fissionable isotope required to sustain a self-amplifying nuclear chain reaction.

Fuel rods

Long tubes in a nuclear reactor core that store fissionable material.

Control rods

Rods made of neutron-absorbing material (such as B or Cd) used to regulate the rate of fission in a nuclear reactor.

Moderator

A material in a nuclear reactor that slows down ejected neutrons to maintain a controlled chain reaction.

Mass defect

The difference in mass between the separate nucleons and the combined nucleus.

Binding energy

The energy released when a nucleus forms from its constituent nucleons; calculated using $E = mc^2$.

Nuclear Transmutation

The transformation of one element into another through a nuclear reaction, often by bombarding a target nucleus with high-energy particles.

Curie (Ci)

A unit of radiation exposure representing $3.7 imes 10^{10}$ decay events per second.

Gray (Gy)

A unit for the amount of energy absorbed by body tissue, defined as $1 ext{ J/kg}$ of tissue.

Rem

A unit of radiation dose defined as "roentgen equivalent man," which accounts for the biological effectiveness of the radiation.

Radiotracers

Radioactive nuclides attached to compounds to track their movement or accumulation within the body for medical diagnosis.