Radioactivity Flashcards
What is Radioactivity ?
Process by which a nucleus of an unstable atom looses energy by emitting ionizing radiation .
What is Ionization radiation ?
Is radiation gives off energy by knocking electrons of atoms which cause the atoms to have a charge .
What are some examples of ionization radiation ?
X-rays,
Gamma rays
Alpha Particles
Neutron Particles
Why are elements so radioactive ?
Hass excess energy
Wants to go ground state
Becomes stable by emitting ionization radiation
They want to achieve a stability in the nucleus
Contains unstable nuclei
Lower energy more stable
Higher energy but less stable .
What are some types of radiation ?
Alpha Particles they don’t go through paper let alone concrete
They have heavier and slower than x-rays and gamma rays because they contain two neutrons and two protons in nuclei
They don’t penetrate skin which x-ray and gamma rays do
Radon is gas which has alpha particles
Beta particles is another type of radiation .Electrons are smaller and faster than alpha particles
They can easily penetrate human skin and can cause tissue damage and burns .
However, very small amounts of some kinds of beta particles emit elements are used in medicine to diagnose /treat diseases of thyroid glands.
Electromagnetic Spectrum
Radio waves are a type of electromagnetic radiation with wavelength with wavelengths in the electromagnetic spectrum longer than infra -red light.
They have frequencies from 300 GHZ to 3KHZ
What are the factors of Longer wavelengths ?
Radio waves
Microwaves
Infra-red
Visible
Longer wavelengths , lower frequency lower energy
What are the factors of shorter wavelength ?
Ultra violet
X-ray
Gamma rays
Shorter wavelengths , with higher frequency , higher energy
What is half life ?
Is the time required for half the atoms of a radioactive material to decay to another nuclear form .
How does ionizing radiation damage DNA ?
It may pass directly through the cell without causing any damage.
It may damage the cell but the cell will repair itself.
It may affect the cell’s ability to reproduce itself correctly, possibly causing a mutation.
It may kill the cell. The death of one cell is of no concern but if too many cells in one organ such as the liver die at once, the organism will die.
What can radiation do to DNA ?
The Alpha, Beta and Gamma particles all add energy to the body’s tissues. The effect is called the Ionizing Energy. It can alter DNA.
Even though Alpha particles are not very penetrative if the decaying atom is already in the body (inhalation, ingestion) they can cause trouble
Where are medical application used and what type of radiation is used ?
Radioisotopes with short half-lives are used in nuclear medicine because they have the same chemistry in the body as the nonradioactive atoms.
In the organs of the body, they give off radiation that exposes a scan giving an image of an organ
What are some sources of radioactivity ?
Primordial radio nuclei :
Present since the creation of earth and have long lives .
Cosmeginic Radio nuclei :
That radionuclides that are produced in the upper atmosphere as a result of cosmic rays interaction with light particles (carbon, Nitrogen and Oxygen), e.g. C14, 7Be, 22Na, 32P, 32S
Anthropogenic Radio nuclei :
Radio nuclei produced as a result of man made activities such as nuclear fuel fabrication, enrichment, nuclear power generation, nuclear accidents etc
Where does Terrestrial radiation occur from ?
The terrestrial component originates from primordial radionuclides in the earth’s crust, present in varying amount.
Radionuclides from these sources are transferred to man through food chains or inhalation.
Extra terrisial radiation
The extra terrestrial radiation originates in outer space as primary cosmic rays.
The primary cosmic rays mainly comprise charged particles, ionised nuclei of heavy metals and intense electromagnetic radiation.
Where does artificial radio nuclei occur from ?
Artificial Radionuclides
of operation of the nuclear fuel cycle, nuclear tests (mainly atmospheric) and nuclear accidents
Most of the artificial radioisotopes decay -short half-lives. Therefore only a few of them are significant from the point of human exposure.
