Radioactivity Flashcards
Who discovered radioactivity
Antoine Henri Becquerel
unstable of emitting
radiation spontaneously to reach a more
stable state; termed also as radioactive
materials
Radioactive atom
conditions why
substance might be
radioactive
Too many protons
Too many neutrons
Too many neutrons
and protons
fraction or percentage of original number of atoms decaying per
unit time
Decay
The amount of time taken by the radioactive material (RAM) or
radioactive atom to decay to ½ of its original value
Half life
Tc99
I131
I123
Ra223
Ra226
Co60
Cs137
Ir192
Sr90
Mo99
6hr
8 days
13hrs
11 days
1620years
5.26 years
30 years
74 days
28years
66 hrs
describes the rate of radioactive decay and the
quantity of the material present at any given
time.
Radioactivity law
the time required so
that activity of radionuclide is reduced to
50%
Physical half life
the time required for the
body to eliminate half of an administered dosage
of any substance by regular process of
deliberation.
Biological half life
the time required for a
radioactive elimination in the body to be
diminished by 50% as a result of the
combined action of the Radioactive Decay
and Biological Elimination.
Effective half life
excited state last
longer than 10-⁹ second, the term ____ is used
Metastable
Nuclear Families
Isotopes
Isobars
Isotones
Isomers
the process wherein the unstable atom (parent) spontaneously
emits radiation to reach a more stable state (daughter)
Radioactive decay
Any atomic species
characterized by the atomic
mass number (A), protons (Z),
and number of neutron (N
Nuclides
the original
nuclide that undergoes
radioactive decay
Parent nuclides
more
stable nuclide which results from
radioactive decay.
Daughter nuclides
Occurs in heavy nuclides with high atomic number
• It resembles the Helium (He) element
Alpha decay
The relative charge of -1 and a mass of 0.
• The β-decay has a moderate energy and it can be stopped by
approximately 0.5mm aluminum or lead.
Beta decay
Two modes of beta decay
Negatron emissions
Positron emission
s occurs when there are too many neutrons.
• It occurs when a radioactive nuclide with high Neutron and Proton
ratio disintegration
Negatron emissions
It occurs when the radioactive nuclide with an excess of Proton
disintegrates
• The particle emitted is positively charged electron which comes from
the nucleus
Positron emission
Excited state element
• Radionuclide that yields another nuclide during disintegration
• Long-lived radionuclide
Parent nuclides
Ground state element
• Element that results from the radioactive decay of a parent element.
• Short-lived radionuclide
Daughter nuclides
originates from the nucleus
Gamma rays & beta particles
