8.Radioactivity Flashcards
Name of scientists who worked on radioactivity
Henri Bequerel
Marie and Pierre Curie
What did Henri Bequerel do?
Uranium salt caused dark patches on photographic plates wrapped in black paper
What two elements did Marie discover ? How?
Polonium
Radium
Isolated &extracted from uranium ore (pitchblende)
Alpha particle composition
2p + 2n (Helium)
Example of alpha particle
Americium 241
Beta particle composition
-fast moving electrons
How are beta particles made?
neutron —> proton + electron
What stops beta particles?
5mm aluminum
Example of beta particle
carbon 14
What’s gamma radiation
High energy electromagnetic radiation like Xrays
How fast does gamma travel
Speed of light
What deflects gamma
Nothing ; no charge
What stops gamma
Thick slab of lead
Example of gamma
Cobalt 60
Radioactivity
Radioactivity is the spontaneous breaking up of unstable nuclei with the emission of one or more types of radiation .
What is used to measure radiation
Geiger muller tube connected to a ratemeter
Nuclear reaction
A nuclear reaction is a process that alters the composition, structure or energy of an atomic nucleus.
4 changes to discuss between chemical &nuclear reaction
- involves electrons
- no new element
- nuclear radiation
- chemical bond breaking/formation
Half life
Half life of an element is the time taken for half the nuclei in any given sample to decay.
Radioisotope
Radioisotope is a radioactive isotope.
Radiocarbon dating
Radiocarbon dating is a technique used to determine the age of an object containing carbon. It is based on the ratio of carbon 12 to c14 in the object.
3 uses of radioisotopes
- Medical
- Food irradiation
- Industrial
what gives the background count on the rate meter
radon gas, rocks, sun
what does the rate meter measure
no. of radioactive particles entering geiger-muller tube per second
