Radioactivity Flashcards
Who discovered radioactivity
Henri Becquerel
What is the definition of radioactivity
The spontaneous breaking up of an unstable nucleus with the emission of one or more types of radiation
What did Pierre and Marie Curie discover
Polonium
Radium
What are the 3 types of radiation
Alpha particles
Beta particles
Gamma rays
What does alpha particles consist of
2 protons and 2 neutrons
have a positive charge
What is alpha particles penetrating power
can penetrate very little
stopped by a few cm of air , sheet of paper , human skin
What is an example of alpha particles and where are they used
Americium 241
Smoke alarms
What do beta particles consist of
high energy electrons emitted from nucleus
formed when a neutron is changed to form a proton and an electron
What is the penetrating power of beta particles
More penetrating than alpha particles
stopped by 5mm of Al
What is an example of beta particles and where are they used
Carbon-14 Carbon dating (archaeology)
What do gamma rays consist of
high energy electromagnetic radiation
What is the penetrating power of gamma rays
very penetrating , only stopped by a thick layer of lead
What is an example of gamma rays and where are they used
Cobalt 60
killing tumours - cure cancer (medicine)
food preservation - irradiation of food , increasing shelf life
What are radioisotopes
radioactive isotopes
isotopes that are unstable and give out radiations
What is the definition of half-life
the half-life of an element is the time taken for half of the nuclei in any given sample to decay
What is used to detect radiation / measure radioactivity
The Geiger-Muller tube
What is a nuclear reaction
a process that alters the composition, structure or energy of an atomic nucleus
What are some differences between nuclear reactions and chemical reactions
Nuclear Reactions :
new element may be formed , changes occur in nucleus , no chemical bonds broken or formed
Chemical Reaction :
new element not formed , no change in nucleus , chemical bond-breaking and forming occurs
What happens when an isotope undergoes beta decay
atomic number increases by 1 and mass number stays the same
becomes next element in P.T + e-1
What happens when an isotope undergoes alpha decay
the atomic number decreases by 2 and the mass number decreases by 4
becomes element 2 places before in P.T (mass of parent atom decreases by 4)
+ He
Where is radiation found
radioactivity is everywhere
radon in granite
carbon-14 in bones
