Atomic Theory 4 - Radioactivity Flashcards
(24 cards)
Scientist responsible
Henri Becquerel
What does the Geiger Muller tube do?
Detects radioactivity
Radioactivity
Spontaneous disintegration of the nucleus with the emission of a,b or y radiation
Alpha particles charge
Positive
Structure of alpha particles
2 protons and 2 neutrons
Penetrability of alpha particles
Not very penetrating
Example of an alpha emitter
Americium-241
Symbol of an alpha particle
4
He
2
Charge of beta particles
Negatively charged
Structure of beta particles
High speed electrons
Penetrability of beta particles
Moderately penetrating (more penetrating than alpha particles)
Symbol of beta particles
0
e
-1
Example of beta emitter
Carbon-14
What change takes place in the nucleus of an atom when beta decay occurs
- Neutron changes into a proton and an electron
- electron is ejected from the nucleus
- ejected electron is the beta particle.
Charge of gamma rays
Neutrally charged
Gamma rays structure
High energy electro-magnetic radiation
Example of gamma ray
Cobalt-60
Penetrability of gamma rays
Extremely penetrating
Nuclear reaction
Involves change in the nucleus of an atom
- new element is usually formed
Chemical reaction
Involves e being shared/transferred from one atom to another
- no change in nucleus
- no new element is formed
Half-life
Time taken for half the nuclei in a given sized sample to decay
Radioisotopes
Isotope of an element that undergoes radioactive decay
Nuclear fission
Splitting of a nucleus into 2 roughly equal fragments
Nuclear fusion
Joining of two smaller nuclei to form a larger one
