Atoms and nuclear radiation Flashcards
What is radioactive decay ?
Radioactive decay is the random process in which a nucleus loses energy by emitting radiation.
What are 4 types of radiation ?
alpha particles, beta particles, gamma rays and neutrons
What are alpha particle made up of ?
positively charged particle consisting of two protons and two neutrons and that is emitted from a nucleus during radioactive decay
How do beta particles form ?
A beta particle forms when a neutron changes into a proton and a high-energy electron
list 4 types of radiation from most ionising to least ionising
Alpha, beta then gamma
What is alpha stopped by ?
A sheet of paper
What is beta stopped by ?
a sheet of aluminium
What is gamma stopped by ?
Thick sheets of lead or metres of concrete
What are isotopes ?
Isotopes are atoms of the same element with different number of neutrons
What is count rate ?
The number of decays recorded each second by a detector
Describe how far each radiation can travel in air ?
Alpha - A few centimetres
Beta - A few metres
Gamma - A long distance
What is alpha decay ?
The atomic number decreases by 2
The mass number decreases by 4
What is beta decay ?
A neutron changes to a proton and electron
The electron is ejected from the nucleus we call that beta particles
The atomic increases by 1 but the mass number stays the same
What is half life ?
Half life is the time taken for the number of nuclei of a radioactive isotope in a sample to halve
It is also the time taken for count rate or activity of a sample to fall to half of its starting value
What is irradiation ?
Irradiation is exposing an object to nuclear radiation ( Alpha, beta, gamma and neutron)
