[Chemistry Class Notes] on Radioactive Elements Pdf for Exam

Everything in our environment is made up of elements, or various types of atoms. Even though these atoms are far too small to see, everything in an object or organism is ultimately made up of these tiny particles. And, while your coffee table or textbook may appear to be quite stable, some elements, particularly those that make up the things in your home, deteriorate over time. These are radioactive elements, which means they release energy and break down into new elements over time.

Let us study what a radioactive element is, its history, uses and more details from this article.

History

Henri-Antoine Becquerel (1852-1908), who discovered radioactivity in 1896, entered a new age of unstable elements. However, an issue occurred: plenty of new elements appeared, each with a different half-life, yet many of them had similar, if not identical, chemical properties.

With his notion of isotopes, Frederick Soddy (1877-1956) explained the problem in 1913, proving that some elements may have differing half-lives but same chemical behaviour – hence, they exist in the “same place” (the Greek term “isos topos”) in the Periodic Table. The source of isotopes became clear when James Chadwick (1891-1974) discovered the neutron in 1932 – isotopes have the same atomic number but varied atomic masses.

Since then, a score of new elements (with many different isotopes) have been found – mostly by planned nuclear reactions – bringing the total number of elements in the modern Periodic Table to 118.

List of Radioactive Elements

The radioactive elements listed below are found naturally in the environment.

Alpha Radiation

When certain radioactive elements decay or break down, they release alpha radiation, which is a type of energy. Uranium and thorium, for example, are two radioactive elements that occur naturally in the Earth’s crust. These two elements slowly change form over billions of years, generating decay products like radium and radon. Energy is released during this process. Alpha radiation is one type of this energy.

Uranium

Uranium is a radioactive element present in soil, water, rocks, plants, and food. Radium and radon are two elements that decay or break down slowly from uranium.

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Radioactive Element Radium

Radioactive element Radium is a radioactive metal that can be found in soil, water, rocks, plants, and food at variable levels across Vermont and the entire Earth. Marie and Pierre Curie are the ones who invented radioactive element radium.

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Radon

Radon is a radioactive gas that is colourless, odourless, and tasteless. Radon is produced by the decay of uranium, a naturally occurring radioactive element found in the Earth’s crust. Uranium decays into radium, which then decays into radon over billions of years.

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Polonium

Polonium (Po-210) is a radioactive element that exists in nature at extremely low concentrations. It can be made in university or government nuclear reactors, but it takes a lot more expertise.

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Only when Po-210 enters the body through breathing, eating, or a wound does it become a radiation hazard. Internal contamination can result in organ irradiation, which can cause serious medical symptoms or death. Po-210 and its radiation pass through intact skin and membranes but not intact skin and membranes. It is not a threat to the body from the outside. The majority of traces can be eliminated with careful washing. It is the most radioactive element.

Half Life of Radioactive Element

Let us study the half life of radioactive elements here.

In radioactivity, the half-life is the time it takes for one-half of a radioactive sample’s atomic nuclei to decay (change spontaneously into other nuclear species by emitting particles and energy), or, alternatively, the time it takes for the number of disintegrations per second of a radioactive material to decrease by one-half.

Cobalt-60, a radioactive isotope used in radiotherapy, has a half-life of 5.26 years, for example. After that time, a sample having 8 g of cobalt-60 will only contain 4 g and emit half as much radiation. The sample would only contain 2 g of cobalt-60 after another 5.26-year period. Because the unstable cobalt-60 nuclei decay into stable nickel-60 nuclei, which remain with the still-undecayed cobalt, neither the volume nor the mass of the original sample decreases visibly.

The half-lives of certain unstable atomic nuclei and the manner in which they decay are features. Alpha and beta decay processes are generally slower than gamma decay. The half-lives of beta decay are up to one hundredth of a second, while alpha decay is up to one millionth of a second. Although gamma emission half-lives have been observed in a wide range, gamma decay half-lives may be too small to detect (about 10-14 seconds).

Uses of Radioactive Elements

• In nuclear power plants, the radioactive elements uranium and plutonium are used to generate electricity.

• In many home smoke detectors, small radioactive sources of particles are used.

• These elements are also used in nuclear weapons manufacture.

Toxicity

Radiation can cause cancer in humans and other living things, even at little amounts. Photons (gamma rays), electrons (beta rays), and helium nuclei (alpha particles) can collide with other molecules and cause structural changes. When this happens to a DNA molecule, the genetic information is damaged, and the cell may become cancerous. In massive doses over short periods of time, radiation can also produce burns, similar to sunburn.

Did You Know?

Because radioactive iodine is easily absorbed by the body and incorporated into bones, it is difficult to eliminate from the body. Long-term exposure to the radiation can lead to bone cancer.

Paint was used to cover the radium on watch dials. Workers used to hand-paint the watch dials, and some would even lick their paint brushes to sharpen the tip. They ingested radon paint, and some developed cancer as a result.

Natural uranium was also used to manufacture bright yellow paint, but I believe that practise has been stopped.