Chemistry ppt radioactivity
- 2. Radioactivity - refers to the spontaneous emission of particles or high- energy electromagnetic radiation from the nuclei of unstable atoms.This occurs due to the disintegration of the atomic nuclei.
- 3. Discovery of Radioactivity In 1898 a French scientist, Antoine Henri Becquerel discovered the the ability for uranium to create a picture when exposed to light. Later, the husband and wife team of Pierre and Marie
- 4. Importance of Radioactivity Radioactivity has an importance mostly when it comes to medicine, but is important for science in general. In medicine, radiation is used as a way of finding tumors within the body and then it is used to destroy them. However, in the realm of science, radiation can also be used to determine the age of the earth as well as the universe, itself. Unfortunately,
- 5. Dangers of Radioactivity Radioactivity can damage cells; can cause burns, diarrhea, vomiting, infertility, migraine and death.A huge amount of radioactivity can destroy many cells that the body cannot replace immediately, because after being inhaled or ingested, the particles
- 6. Advantages and Disadvantages of Radioactivity Radioactivity does have a medical advantage. It is used for treatment of cancer patients to reduce or deplete tumors. Another advantage is that it kills microbes and permits carbon dating to take place. A disadvantage of radioactivity is that using it as a medical treatment does make the reproductive organs sterile. Over-exposure does have negative affects on your health. A large dose that is experienced all at one time
- 7. Types of Radioactivity The types of radioactivity are alpha, beta, and gamma, which are classified according to the charge if the electromagnetic rays they give off. Alpha rays carry a positive charge, beta rays carry a negative one, and gamma rays are neutral.
- 10. • Isotopes are atoms of an element which have the same proton number but different nucleon number. •Some isotopes are referred to as 'stable' and others as 'unstable' or 'radioactive'.
- 11. • Radioisotopes are unstable isotopes which decay and give out radioactive emissions. • Radioisotopes are naturally occuring or artificially produced. • Artificial radioisotopes can be produced when certain nuclides are bombarded by high energy particles.
- 12. PROPERTIES OF RADIOISOTOPES • Emits radioactive radiation. • Radioactive radiations can kill cells. • Radioactive radiations have different penetrating ability with materials of different thickness and densities. • Radioactive radiations can cause cell mutation. • Radioactive radiations can ionize molecules. • Its activity decreases with time. • Radioisotopes have the same chemical properties as non-radioactive isotopes of the same element.
- 13. ARTIFICIAL RADIOISOTOPES Example : When a nucleus of magnesium-24 is bombarded by a neutron,sodium-24 can be produced.
- 15. Medicine To diagnose of thyroid disease using iodine-123 To treat an overactive thyroid gland and certain kinds of thyroid cancer by using sodium iodide labelled with radioactive iodine To detect position of blood clots or thrombosis using Sodium-24 injected in the bloodstream
- 16. To detect and treat brain tumor using phosphorus-32 To study the circulation of iron in the blood using iron-59 To sterilize medical equipments and to destroy cancer cells in radiotherapy radioisotope cobalt-60 is used
- 17. AGRICULTURE To be used as tracers in the effectiveness of fertilizers using nitrogen- 15 and phosphorus -32 To induce genetic mutation in a plant in order to produce a better strain which has higher resistance against pest and diseases
- 18. Pests can be killed using radioactive rays esp. using gamma rays To stop pests from reproducing, induced mutation by using gamma rays can be employed. But this has the probability of producing GMO and resistant pests
- 19. For determining age of fossils older than 60,000 years one uses a potassium-argon dating technique. Potassium dating has a half life of 1.3 billion years, thus allowing the age of rocks several billions years old to be determined. A more accurate "argon- argon" dating technique (determining the ratio between argon-39 and argon-40) has also been developed. C-14 is another radioactive isotope that decays to C-12. This isotope is found in all living organisms. Once an organism dies, the C-14 begins to decay. The half-life of C-14, however, is only 5,730 years. Because of its short half-life, the number of C-14 isotopes in a sample is negligible after about 50,000 years, making it impossible to use for dating older samples. C-14 is used often in dating artifacts from humans.
- 20. To measure geological time. During the formation of rocks, some radioisotopes such as uranium-238 are trapped. As the decay continues, the proportion of uranium-238 decreases slowly resulting in the equally slow growth of its product lead-206. An estimate of the age of the rock can be inferred from the relative proportions of lead and uranium in the rock.
- 21. 1. The thickness of paper, plastics, clothes and metal sheets need to be standardized and this is done by placing a radioactive source at one side of the material and a detector on the other side. 2. For sheets of metal, gamma ray is used. For plastics, clothes and paper, beta particles are used. 3. The detector will register a higher count if the material is too thin and lower register if too thick. The computer will make adjustments according to the thickness of the material.
- 22. This mechanism is also used to ensure that containers such as cans and food packages are filled to the specified amount. Radioisotope is added to engine oil so that its level of wear and tear can be determined. In order to kill germs that cause food to spoil quickly, gamma rays are used. If exposed to gamma ray, latex becomes harder without the need for adding sulphur.
- 23. THANKYOU FOR WATCHING DONE BY: RISHITA SINGH