Radioactivity Flashcards
Discovery of radioactivity
Becquerel
Cathode tubes
Roentgen
Term of radioactivity
Currie
Atoms mass must be concentrated in an small positive charged
Rutherford
Radioactive decay found by
Rutherford
What is radioactivity
Spontaneous emission of radiation
Alpha , beta , gamma from nucleus
If a nucleus is unstable it will emit and absorb particles
In order to reach that stability it releases its extra energy by emitting particles or transforming that energy
What is Radioactive decay
The process of an unstable nucleus becoming stable by spontaneously emitting particles
What is Ionization
The excess amount of energy that unstable nucleuses—removal of electrons from atoms
Uncertain
If there is still excess energy= secondary ionization
What is excitation
If the energy transfer is not sufficient to cause ionization.
Transfer of energy to an orbital electron and raising the electron to a higher orbital or energy level.
ONLY DEPENDS ON THE AMOUNT OF ENERGY
Half life
Period within which a nucleus has 50% chance of decaying
T1/2
Rate of decay
Number of disintegration per unit time
Proportional to the number of unstable nuclei.
Average life
Reverse of decay constant
T0= 1/ decay constant
Biological half life
Time it takes for a subs to lose half of is radiologic activity
Effective half life
rate of accumulation, elimination of a biochemical subs in an organism
Belt of stability
Characterization of the stability of nuclides to radioactivity based on their binding energy.
Non-radioactive isotopes exist based on their ratio of neutrons and protons
Nuclei which do not fall within the belt of stability called?
Radioactive
Heavier elements in belt of stability?
Light elements in belt of stability?
Light= non-radioactive nuclei contain approximately equal number of protons and neutrons
Heavier = non-radioactive nuclei contain more neutrons than protons.
Origins of X-rays and Gamma rays
X-rays: from electron transitions, orbitals
Gamma: from nucleus
Radioactivity unaffected by
Temperature
Pressure
Physical state
Decay modes?
Alpha decay
Beta decay
Gamma decay
Spontaneous fission
Delayers neutron and proton emission
Two proton decay
Composite particle emission
Double beta decay
The transition of a neutron into a proton?
If the unstable nucleus is above the belt
Release of a NEGATRON from nucleus
The transformation of a proton into a neutron?
Unstable nucleus below the belt of stability
Release of a POSITRON from the nucleus= p/n increases
Capturing an extra nuclear electron usually from K shell= K-CAPTURE
What kind of a decaying happens when unstable nucleus is beyond the belt of stability
Emission of an alpha particle from the nucleus
Z bigger than 83
Too many p so unstable
In the decays conversion of ?
Energy
Momentum
Electric charge
Number of nucleons
