Physics – atomic structure

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Radius of atom
10^-10m
Radius of nucleus
1/10000 times smaller than atom radius
Isotope
Same number of protons, different number of neutrons
JJ Thompson
Plum pudding model
Rutherford and Marsden
Nuclear model
Bohr
Energy levels
Chadwick
neutrons
Unstable isotopes
decay randomly and emit radiation
Activity of a source
how quickly it decays
Count – rate
Geiger Mueller tube and counter
1 Becquerel
1 decay/second and 1 count/second
Short half life
Nucleus is more unstable and the source is more active
Radiation uses
Medical tracers and radiotherapy
Irradiation
Kills germs and viruses
Radiation dosis
mSv – millisievert
Background radiation
Low level radiation from buildings, soil, space (cosmic rays), nuclear explosions
Neutron radiation
Free neutron emmitted as a result of nuclear fission
Fission
Splitting of a large, unstable atom into smaller atoms
Fusion
Joining of two light nuclei to form a heavy nucleus
Contamination
Unwanted radioactive atoms get onto an object
Categories: Atomic Physics