Chemistry - Ch 21 Flashcards
Nuclide
Nucleus with a specified number of protons & neutrons
Nucleons
Subatomic particles of the nucleus (protons & neutrons)
Radionuclides
Nuclei that are radioactive
Radioisotopes
Atoms containing radioactive nuclei
Alpha Particles
Helium-4 particles
Beta particles
High-speed electrons emitted by an unstable nucleus
Gamma radiation
High-energy photons (electromagnetic radiation of very short wavelength)
Positron
Particle that has the same mass as an electron but an opposite charge
Electron capture
Capture by the nucleus of an electron from the electron cloud surrounding the nucleus
Radioactive series (nuclear disintegration series)
Series of nuclear reactions that begins with an unstable nucleus and terminates with a stable one
Magic numbers
Numbers of protons and neutrons that result in very stable nuclei
Nuclear transmutations
Nuclear reactions induced by a nucleus changing its identity if it is struck by a neutron or other nucleus
Particle accelerators
Method devised to accelerate charged particles using strong magnetic and electrostatic fields
Transuranium elements
Elements with atomic number above 92 produced with artificial transmutations
Half-life
Time required for half of any given quantity of a substance to react
Activity
Rate at which a sample decays
Becquerel (Bq)
SI unit for expressing the activity of a particular radiation source (rate at which nuclear disintegrations are occurring)
Curie (Ci)
3.7 x 10^10 disintegrations per second (rate of decay of 1g of radium)
Radiotracer
Radioisotope used to trace the path of the element
Mass defect
Mass difference between a nucleus and it’s constituent nucleons
Nuclear binding energy
Energy required to separate a nucleus into its individual nucleons
Fission
Heavy nuclei gain stability and therefore give off energy if they are fragmented into two mid-sized nuclei; used to generate energy in nuclear power plants
Fusion
Even greater amounts of energy are released if very light nuclei are combined or fused together to give more massive nuclei; essential energy-producing process in the sun
Chain reactions
Reactions that multiply
Critical mass
Amount of fissionable material large enough to maintain the chain reaction with a constant rate of fission
Supercritical mass
Mass in excess of critical mass
Thermonuclear reactions
Fusion reactions
Ionizing radiation
Radiation that causes ionization
Non-ionizing radiation
Of lower energy such as radio frequency electromagnetic radiation
Free radical
Substance with one or more unpaired electrons
Gray (Gy)
SI unit of absorbed dose; corresponds to the absorption of 1J of energy per kilogram of tissue
Rad
Radiation absorbed dose; absorption of 1 x 10^-2J of energy per kilogram of tissue
Rem
Roentgen equivalent for man
