P4-Atomic Structure KW 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
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.
Ions
Atoms with a resultant charge due to the loss or gain of electrons
Irradiation
The process of an object being exposed to nuclear radiation. The object doesn’t become radioactive.
Isotopes
Atoms with the same number of protons but different numbers of neutrons. The atomic number is the same, but the mass number is different.
Mass Number
The number of protons and neutrons in an atom
Negative Ions:
Atoms that gained electrons and so have a resultant negative charge.
Neutrons
A neutrally charged constituent of the nucleus.
Nuclear Explosions:
Nuclear explosions in nuclear weapons are caused by an uncontrolled chain reaction which results in vast quantities of energy being produced in a very small period of time.
Nuclear Fission
The splitting of a large and unstable nucleus into two smaller and more stable nuclei to produce energy.
Nuclear Fusion
The joining of two small, light nuclei to form a larger, heavier one and release energy
Nucleus
The positively charged centre of an atom, containing protons and neutrons
Plum Pudding Model
An old model of the atom that represented the atom as a ball of positive charge, with negative charges distributed throughout it.
Positive Ions
Atoms that have lost electrons and so have a resultant positive charge.
Protons
A positively charged constituent of the nucleus.
Radioactive Contamination
The unwanted presence of radioactive atoms on other materials. It is hazardous due to the decay of the contaminating atoms.
Radioactive Decay
The random process involving unstable nuclei emitting radiation to become more stable.
Sieverts
The unit used for radiation dosage
Spontaneous Fission
Fission that occurs without the absorption of a neutron. Spontaneous fission is rare and in most cases, fission is induced with a neutron.
