Some elements have more than one atomic mass but have the same electrical charge on their nucleus and chemical properties. Such element variants are called isotopes.

Examples of isotopes are-

1. Isotopes of Carbon

Carbon-11, Carbon-12, carbon-13, and carbon-14 are three isotopes of the element carbon with mass numbers 12, 13, and 14 respectively. The atomic number in all isotopes remains the same (6), however, the number of neutrons in the isotopes are 6,7, and 8 respectively.

12C, 13C, 14C

Uses of Carbon Isotopes-

a.Carbon 11 is used in positron emission tomography scanning or PET scan.

b.Carbon 14 is used in dating fossils.

The relative concentration of isotope variants of carbon is nearly constant in living organisms. However, when the dead organism decay, the carbon 14 radioactive isotopes start disintegrating this phenomenon can be used in dating fossils.

2. Isotopes of hydrogen

Protium, Deuterium, and tritium are the three isotopes of hydrogen.

A. Deuterium is also known as heavy water and is used as a coolant in nuclear reactors.

B. While Protium is the fuel for nuclear fusion in the solar cycle.

C. Tritium-

a. It is an important component of nuclear weapons.

b. In making self-power lighting devices called beta lights. Which are used in night vision goggles and watches. This takes the place of radium which can cause bone cancer.

3. Isotopes of Uranium

Uranium 238 is abundant in nature and does not show fission properties. On the other hand, uranium 239 is radioactive and is used as a fuel in the first stage nuclear program. Similarly, uranium 233 radioactive isotope is used with thorium in the third stage nuclear program of India.

4. Isotopes of Cobalt are

Cobalt 59 and Cobalt 60.

Cobalt 60 is radioactive it converts into cobalt 59 (standard isotope) by emitting gamma rays.

The gamma rays are very energetic and are used to kill microorganisms and cancerous cells.

Uses of cobalt 60 –

Food processing- in India radiation processing unit KRUSHK has been set up by BARC for radiation processing for food preservation.

5. Isotopes of Holmium are Holmium 164 and Holmium 166

Holmium 166 is used for the treatment of arthritis.

6. Isotopes of Samarium

Samarium 150 and Samarium 153C

Radioactive Samarium 150 is used for the treatment of arthritis.

7. Isotopes of Cesium

Cesium 132 and Cesium 137

Cesium 132 is used in brachytherapy (Radiotherapy in which the source of irradiation is placed close to the surface of the body or within a body cavity).

8. Isotopes of Iodine

Iodine 126, Iodine 125, and Iodine 131

Iodine is used in nuclear imaging of the thyroid gland.

Iodine 131 is used in the treatment of hyperthyroidism (Graves’s disease).


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