Topic 4 - Atomic Structure Flashcards
(23 cards)
Alpha Particle
A positively charged particle consisting of two protons and two
neutrons.
Activity
The rate at which an unstable nucleus decays.
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.
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.
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.
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.
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.
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.
