radioactivity- chemistry

what are the elements discovered by henry Becquerel and Marie and Pierre Curie

polonium and radium

what are alpha particles

groups of two protons and two neutrons stuck together

properties of alpha particles

• have a large mass

• travel slowly

• have a low penetrating power stopped by a sheet of paper

what is an example of a radioactive element that emits alpha particles

americium 241 found in smoke detectors

what is radioactivity

the spontaneous breaking up of unstable nuclei with the emission of radiation

what are beta particles

fast moving electrons

when are beta particles formed

when a neutron in an unstable nucleus is changed to a proton and electron

properties of beta particles

• travel fast

• more penetrating that alpha particles

• can penetrate up to 5 millilitres of aluminium

examples of elements that emit beta particles

carbon 14 used in carbon dating

what is gamma radiation

high energy electromagnetic radiation

properties of gamma rays

• does not consist of charged particles

• is not deflected in electric or magnetic fields

• an unstable nucleus emits gamma rays to lose surplus energy

• have a high penetrating power and are only stopped by a thick slab of lead

example of element that gives off gamma rays

cobalt 60 used in hospitals

what is a nuclear reaction

a process that alters the composition, structure or energy of an atomic nucleus

what is the half life

the time taken for half of the nuclei in any given sample to decay

what is used to find the half life

geiger muller tube and ratemeter

what a radioisotope

a radioactive isotope

what are the differences between chemical and nuclear reactions

in nuclear reactions a new element is formed and changes take place in the nucleus