!-Radioactivity
Radioisotopes
A Radioisotope (radionuclide) is an atom with an unstable nucleus.
Transmutation
Change of one element into another
Beta
Electrons Formed when a neutron decays into a proton and an electron Penetrate 5mm of aluminum Carbon-14 used in carbon-dating emits beta particles
Nuclear reactions
Emission of radioactive radiation In a nuclear reaction the nucleus forms a new element
Gamma
High energy electromagnetic radiation Not deflected by magnetic or electric fields Only stopped by several cms of lead. Cobalt-60 [used to treat cancer] emits gamma rays
Antoine Henri Becquerel
In 1896, while investigating uranium salts, Becquerel accidentally discovered radioactivity . Becquerel found that the photographic plates were fully exposed when in contact with radioactive salt.
Radioactivity
Is the spontaneous breaking up of unstable nuclei with the emission of one or more types of radiation There are three types alpha, beta and gamma
Alpha
Made of 2 protons + 2 neutrons Helium nucleus From unstable nuclei Low penetration; stopped by a sheet of paper Americum-241 [used in smoke detectors] emits alpha particles
Loss of an alpha particle
Mass decreases by 4 Atomic number decreases by 2 Radium-226 Radon-222 + alpha particle
Beta loss
Mass number stays the same Atomic number increases by 1 Carbon-14 --> nitrogen-14 + beta
Beta loss⁻>
Mass number stays the same Atomic number increases by 1 Carbon-14 --> nitrogen-14 + beta
Uses of radiation
Medical—.gamma rays kill cancerous cells and sterilises equipment Archaeological—after a living thing dies the amount of C-14 decreases. Used to determine the age of a plant/animal Food—gamma rays kill disease causing organisms
Pierre Curie
Pierre discovered nuclear energy, by identifying the continuous emission of heat from Radium particles. He also investigated the radiation emissions of radioactive substances, which lead to the discovery of Alpha, Beta and Gamma radiation.
Half life
Time taken for half of the nuclei in any given sample to decay
