zara woollard
9.1 | 2019
Radioactive decay occurs when an isotope has an unstable nucleus, and emits particles or photon waves.
alphA radiation
Alpha radiation, with the symbol α, is the least harmful and least strong form of radiation. It is created when an isotope experiences alpha decay. If a substance such as Uranium-234, which has 92 protons and 142 neutrons, undergoes a decay event, it will change into a thorium atom, and an alpha particle. An alpha particle is equivalent to the nucleus of a helium atom – 2 neutrons and two protons. When uranium-234, which has 92 protons and 142 neutrons, loses two protons and two neutrons, it has 90 protons and 140 neutrons. Because the number of protons has changed, it is now Thorium. A total of four particles from the nucleus have been removed, so the atomic mass is now 230. The result of uranium undergoing alpha decay is thorium-230. This is a stable isotope of thorium. The alpha particle that remains is basically harmless to living things, it will bounce of human skin, and it can be blocked by a thin sheet of paper. It is the same size as a helium nucleus, so the only area of the body it can damage from the outside is the cornea of the eye. However, if it is ingested or inhaled, it can cause damage.
The word equation for alpha radiation of uranium-234 is:
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IMAGE 3: Alpha radiation formula
IMAGE 1: Uranium experienceing alpha decay
BETA RADIATION:
Beta radiation, with the symbol β, is the second strongest form of radiation, which can travel through the human skin into organs, and can pass through paper but is stopped by aluminium. It occurs when an isotope experiences a decay event. One of the neutrons in the nucleus of the original particle will split into a proton and an electron, the former which changed the element and the latter, which is released into the air as a beta particle. An example is when thorium-210 becomes protactinium-210, and a beta particle, which is just an electron. If it were an isolated case, it would be harmless, as we are surrounded by lose electrons daily. When beta decay happens on a larger scale, electrons exist in the air in a more concentrated form and it becomes harmful. Here is the worded equation for this decay event, along with the formula for beta radiation.
IMAGE 2: Thalium experienceing beta deacy
IMAGE 4: Beta decay formula
GAMMA RADIATIOn:
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Gamma radiation, with the symbol γ, occurs when a radioisotope has an unstable nucleus. This nucleus attempts to become stable by moving the particles in it's nucleus, and while it is doing this it is creating nuclear energy. The nuclear energy becomes high frequency electromagnetic radiation. These electromagnetic waves are made of photons, massless particles possessing energy that travel at the speed of light. In the EMR (electromagnetic) spectrum, gamma waves have the highest amount of energy. Their waves also have the shortest wavelenghts on the spectrum.This type of radiation is the most lethal, as it is the thinnest form of radiation. It can penetrate a few centimetres of led, and human bones, and too much exposure to it increases the risk of cancerous cells developing.
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IMAGE 5: gamma radiation
IMAGE 6: A diagram showing the strength of each type of radiation:
