Every day, countless natural phenomena occur around us, many of which go unnoticed. One such phenomenon is radioactivity, a property of matter that results in the spontaneous emission of energy in the form of subatomic particles. This article takes a closer look at radioactivity, focusing particularly on alpha decay.
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Radioactivity is a phenomenon that occurs due to the instability of an atom's nucleus. This instability leads to the emission of radiation, resulting in energy loss. There are two forces at play within the nucleus - the electrostatic force of repulsion and the powerful nuclear forces of attraction. These forces are incredibly strong, but as the size of the nucleus increases, so does the likelihood of instability. This is why heavy atoms like Uranium and Plutonium are highly unstable and exhibit radioactivity.
The concept of radioactivity was discovered somewhat accidentally by scientist Henry Becquerel. He found that a Uranium compound had exposed photographic plates, even though they were wrapped in black paper. This led to the understanding of radioactive decay, which can occur in three forms: gamma decay, beta decay, and alpha decay.
There are three primary types of radioactive radiations, each resulting from different types of decay. These are represented by α, β, and γ rays. The mathematical representation of each is as follows:
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Alpha decay is a type of radioactive decay in which an unstable atomic nucleus emits an alpha particle (a helium nucleus) and transforms into a more stable element. The ejected alpha particle consists of two protons and two neutrons, making it identical to a helium atom's nucleus. The atomic number of the radioactive sample changes as the alpha particle exits the nucleus. The remaining element after alpha decay is two atomic numbers lesser and four mass numbers lower. For instance, Uranium-238 decays to form Thorium-234.
The nuclear transformation in an alpha decay can be expressed as follows:
Alpha decay typically occurs in heavy elements with large or unstable nuclei. It is the most common form of decay in such elements. The emitted alpha particles usually have an energy level of around 5 MeV and travel at about 5% of the speed of light. Alpha particles carry a +2 charge due to the absence of electrons, making them highly reactive. This reactivity, combined with their large mass, means that alpha particles lose their energy almost immediately upon emission. A few centimeters of air can stop their forward motion.
The high ionizing power of alpha particles can have harmful effects on human tissue. Overexposure to alpha radiation can cause blisters and burns.
Radioactivity has numerous practical applications. Here are a few examples:
Like any scientific phenomenon, radioactivity has its advantages and disadvantages.
Advantages of radioactivity include:
Disadvantages of radioactivity include:
What is meant by the half-life of an isotope?
The half-life of an isotope is the average time it takes for half of the atoms to decay.
List a few uses of radioactivity.
Following are a few uses of radioactivity: Used in domestic smoke detectors, Used to sterilize medical instruments, Used to diagnose and treat diseases, Used to produce electric power.
Define radioactivity.
Radioactivity is a phenomenon exhibited by a few matters of emitting energy and subatomic particles spontaneously. Radioactivity is due to the nuclear instability of an atom.
Who discovered radioactivity?
Henry Becquerel.
What is the relationship between Curie and Rutherford?
1C = 3.7 × 104 Rd.