atomic structure physics
activity
the rate in which an unstable nucleus decays
alpha particle
particle with a positive charge consistsing of 2 protons and two neutrons
atomic number
number of protons found in an atom or specific element.
backround radiation
radiation found in small quantities all around us. Originates from natural sources such as rocks etc and from man made sources such as nuclear weapons testing
bequerel
unit of radioactive activity
beta particle
hight speed electron that a nucleus emits when a neutron converts into a proton
bohr model
model of the atom that suggested electrons orbit the nucleus at set distances
chain reaction
process of neutrons released by a fission reaction being absorbed by another unstable, large nuclei and inducing further fission
count rate
number of decays a detector measures per second
electrons
negatively charged subatomic particle that are found in shells in orbit of the nucleus
energy levels
stable states where electrons are found around a nucleus. Absorbtion of electromagnetic raditation causes a transition to a higher energy level and emission causes a transition to a lower energy level.
fission products
fission produces teo smaller nuclei, teo 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
detector that measuress the count rate of a radioactive sample
half life
time it takes for the number of unstabke nuclei of an isotope in a sample to halve. Or the time that it takes the initial count rate of the sample of the isotope to halve.
ions
atoms with a resultant charge due to the loss or gain of electrons
irradiation
process if an object being exposed to nuclear radiation. The object doesnt become radioactive
isotopes
atoms with the same number of protons and a different number of neurtrons. Atomic number stays the same, the mass number changes.
mass number
number of protons and neutrons in an atom
negative ions
atoms that gained electrons so have a resultant negative charge
neutrons
neutrally charged subatomic particle
nuclear explosions
caused by an uncontrolled chain reaction which results in vast amounts of energy being released in a short space of time
nuclear fusion
joining of two small light nuclei to form a larger, heavier one and release energy
nuclear fission
splitting of a large unstabke nucleus into teo smaller and more stable nuclei to produce energy
nucleus
postitvely charged centre of an atom
plum pudding model
old model of the atom that showed it as a ball of positive charge with negative electrons embedded in it
positive ions
atoms that have lost electrons there fore have a resultant positive charge
protons
positively charged subatomic particle
radioactive contamination
unwanted prescence of radioactive atoms on other materials. It is hazardous due to the decay of the contaminating atoms.
radioactive decay
random process involving unstable nuclei emitting radiation to become more stable
sieverts
unit used for radiation dosage
spontaneous fission
fission that occurs without the absorbtion of a neutron. This is rare.