Juliette’s Chapter 25 Chem. Summary: Nuclear Chemistry
Radioactivity
The process by which materials give of rays emitted by uranium atoms.
Radiation
The penetrating rays and particles emitted by a radioactive source.
Radioisotopes
The nuclei of unstable isotopes.
Key: An unstable nucleus releases energy by emitting radiation during the process of radioactive decay.
Key: An unstable nucleus releases energy by emitting radiation during the process of radioactive decay.
Key: The 3 main types of nuclear radiation are alpha radiation, and gamma radiation.
Alpha Particle
A particle that contains 2 protons and 2 neutrons and has a double positive charge.
Beta Particle
An electron resulting from the breaking apart of a neutron in an atom.
Gamma Ray
A high-energy photon emitted by a radioisotope.
Nuclear Force
An attractive force that acts between all nuclear particles that are extremely close together, such as protons and neutrons in a nucleus.
Band of Stability
The region in which we know the number of protons for all known stable nuclei.
Key: The neutron-to-proton ratio determines the type of decay that occurs.
Positron
A particle with the mass of an electron but a positive charge.
Half-life (t1/2)
The time required for 1/2 of the nuclei of a radioisotope sample to decay to products.
Key: After each half-life, half of the existing radioactive atoms have decayed into atoms of a new element.
Transmutation
The conversion of an atom of 1 element to an atom of another element.
Key: Transmutation can occur by radioactive decay. Transmutation can also occur when particles bombard the nucleus of an atom.
Trans-uranium Elements
The elements in the periodic table with atomic numbers above 92.
Fission
The splitting of a nucleus into smaller fragments.
Key: In a chain reaction, some of the neutrons produced react with other fissionable atoms, producing more neutrons which react with still more fissionable atoms.
Neutron Moderation
A process that slows down neutrons so the reactor fuel captures them to continue the chain reaction.
Neutron Absorption
A process that decreases the number of slow-moving neutrons.
Key: Water cools the spent rods, and also acts as a radiation shield to reduce the radiation levels.
Fusion
When nuclei combine to produce a nucleus of greater mass.
Key: Fusion reactions, in which small nuclei combine, release much more energy than fission reactions, in which large nuclei split.
Ionizing Radiation
Radiation with enough energy to knock electrons off some atoms of the bombarded substance to produce ions.
Key: Devices such as Geiger counters, scintillation counters, and film badges are commonly used to detect radiation.
Geiger Counter
A gas-filled metal tube used to detect radiation.
Scintillation Counter
A phosphor-coated surface used to detect radiation.
Film Badge
Several layers of photographic film covered with black lightproof paper, all encased in a plastic or metal holder.
Neutron Activation Analysis
A procedure used to detect trace amounts of elements in samples.
Key: Radioisotopes can be used to diagnose medical problems, and in some cases, to treat diseases.