Nuclear Chemistry: Practice Flashcards

Vocabulary-style flashcards covering key terms and concepts in nuclear chemistry, including radiation types, decay processes, fission, and fusion.

Nuclear radiation

A form of ionizing radiation that results from the changes in nuclei of atoms.

Radioactivity

The emission of energetic particles and photons from unstable atomic nuclei.

Radioisotopes

Elements that emit radioactivity.

Nucleons

Protons and neutrons that make up the nucleus.

Strong nuclear force

The force that holds nucleons together and overcomes the repulsion between protons; it has a very short range, about the diameter of a nucleon.

Nuclide

A type of atom specified by its atomic number, atomic mass, and energy state.

Radioactive decay

The process during which parts of a nucleus break off and are emitted as particles, changing the number of protons in the nucleus.

Alpha particle ($\alpha$)

A group composed of two protons and two neutrons emitted as a radioactive particle; equivalent to a helium nucleus ($^{4}_{2}\text{He}^{2+}$).

Beta particle ($\beta$)

A rapidly-moving electron ($^{0}_{-1}\text{e}$) emitted from a nucleus when a neutron converts into a proton and an electron.

Gamma ray ($\gamma$)

High-energy electromagnetic radiation emitted by radioactive substances with very high frequency and extremely short wavelength.

Positron

A positively charged electron ($^{0}_{+1}\text{e}$) that has the same mass as a regular electron; it is considered a form of antimatter.

Decay series

The predictable pattern of transmutations a radioactive atom undergoes on its way to becoming a stable element.

Half-life

The amount of time it takes for half of the atoms in a sample to decay to the next step in their decay series.

Radioisotopic dating

Any method that uses the concentration and decay rate of a radioactive substance to establish the age of an object.

Fission

The splitting of a heavy nucleus to create two or more lighter nuclei, releasing large amounts of energy.

Chain reaction

A type of repeating nuclear reaction that starts with the splitting of a heavy nucleus, such as ${}^{235}\text{U}$, and continues as long as sufficient nuclear material remains.

Critical mass

The quantity of a radioactive material necessary to sustain a fission chain reaction.

Nuclear reactor

A reactor in which a controlled nuclear fission is used to generate power.

Fuel rods

Long metal rods containing enriched uranium-235 fuel in the form of uranium oxide pellets.

Control rods

Rods of material, such as boron or cadmium, that absorb neutrons in a nuclear reactor to regulate the chain reaction.

Moderator

A substance, such as water, that surrounds the fuel assembly in a reactor to slow down neutrons.

Fusion

A nuclear reaction where the nuclei of two light elements merge to form the nucleus of a heavier element, such as hydrogen atoms fusing to become helium.

Plasma

A state of matter at extremity high temperatures composed of separate electrons and positive nuclei, necessary for fusion reactions.