Introduction
Element 36, also known as selenium, is a chemical element with the symbol Se and atomic number 34. It is a nonmetal and a member of the chalcogen group in the periodic table. Selenium is found naturally on Earth and has several important applications in various industries. Selenium was first discovered in 1817 by Swedish chemist Jöns Jacob Berzelius, who isolated it from copper pyrite ore. However, its properties were not well understood until the early 20th century. Today, selenium is an essential nutrient for many living organisms and a key component of various biological systems.
Key Points
1. Occurrence and Abundance
Selenium is found naturally in small amounts in the Earth’s crust. It is often associated with copper, zinc, and lead ores. The largest deposits of selenium are found in Spain, Poland, and China. 2. Physical Properties
Selenium has a number of distinctive physical properties. It is a nonmetal with an atomic weight of 78.96 and a melting point of 223°C. Selenium is also highly resistant to corrosion and oxidation. 3. Chemical Reactions
Selenium exhibits a range of chemical reactions, including formation of selenium dioxide when it reacts with oxygen. It also forms compounds with other elements, such as hydrogen and chlorine. 4. Biological Role
Selenium is an essential nutrient for many living organisms. It plays a crucial role in the production of selenoproteins, which are proteins that contain selenium. Selenium is also involved in antioxidant reactions and protects cells from damage caused by free radicals. 5. Applications
Selenium has several important applications in various industries. It is used as a semiconductor material in computer chips and solar panels. Selenium is also used in the production of batteries, glass, and ceramics. 6. Toxicity and Environmental Impact
Selenium can be toxic to humans if ingested in large amounts. It is found naturally in small amounts in food and water, but excessive consumption can lead to health problems. Selenium is also released into the environment through industrial processes and can accumulate in soil and water. 7. History of Use
Selenium has been used by humans for thousands of years. The ancient Egyptians used selenium-rich minerals to treat skin conditions. In the 19th century, selenium was used as a medicine to treat syphilis and other diseases. 8. Current Research
Researchers are currently studying the properties and applications of selenium. They are exploring its use in new technologies, such as solar panels and water purification systems. Selenium is also being studied for its potential health benefits, including its role in cancer prevention and treatment.
Conclusion
Selenium is an essential element with a range of unique properties and applications. Its importance extends beyond its industrial uses to its biological functions and environmental impact. As researchers continue to study selenium, we are likely to discover new and innovative ways to harness its power.