4: Atomic Structure Flashcards
Activity:
The rate at which an unstable nucleus decays.
Alpha Particle:
A positively charged particle consisting of two protons and two neutrons.
Atomic Number:
The number of protons found in an atom of a specific element. Each element has a different atomic number.
Background Radiation:
Radiation that is found in small quantities all around us and originates from natural sources such as rocks and cosmic rays, as well as from man-made sources such as nuclear weapons testing and accidents.
Becquerel:
The unit of radioactive activity.
Beta Particle:
A high speed electron that a nucleus emits when a neutron converts into a
proton.
Bohr Model:
A model of the atom that suggested that electrons orbit the nucleus at set
distances.
Chain Reaction:
The process of neutrons released by a fission reaction, being absorbed by another unstable, large nuclei, and inducing further fission.
Count-Rate:
The number of decays that a detector measures per second.
Electrons:
A negatively charged constituent of the atom, that are found in different energy levels, around the nucleus.
Energy Levels: (and how electrons can transition between them)
The stable states in which electrons are found in around a nucleus. Electrons can transition to a higher energy level through the absorption of electromagnetic radiation and can transition to a lower energy level through the emission of electromagnetic
radiation.
Fission Products:
Fission produces two smaller nuclei, two or three neutrons and gamma rays. All these products are released with kinetic energy.
Gamma Ray:
Electromagnetic radiation emitted from a nucleus.
Geiger-Muller Tube:
A detector that measures the count-rate of a radioactive sample.
Half-Life:
The time it takes for the number of unstable nuclei of an isotope in a sample to
halve, or the time it takes for the initial count rate of a sample of the isotope to halve.