Chemical properties. Selenium is a non metallic chemical element, member of the group XVI of the periodic table. Selenium is a non metallic chemical element, member of the group XVI of the periodic table. Selenium exists in an amorphous powder form in chemical reactions. Unlike sulfur, selenium is a semiconductor, meaning that it conducts some electricity, but not as well as conductors. Find physical and chemical properties of Selenium (Se) like element name, symbol, atomic number, atomic weight, density, color, melting point, boiling point, physical state at room temperature, isotopes, compounds, half life period, category, year of discovery and more In chemical activity and physical properties it resembles sulfur and tellurium.Selenium appearsin a number of allotropic forms: the most popular are a red amorphous powder, a red crystalline material, and a gray crystalline metallike form called metallic selenium. Crystalline monoclinic selenium is a deep red; crystalline hexagonal selenium, the most stable variety, is a … Most people get enough of this essential mineral from foods, and taking too much may lead to health problems. Selenium is a moderately reactive element combining with hydrogen, chlorine, fluorine, and bromine (Chemistryexplained 2012). Selenium is mostly noted for its important chemical properties, especially those dealing with electricity. Chemical properties of Selenium 34 Se Selenium 78.971 Period: 4 Melting Point: 217 Boling Point: 685 Vanderwaals Radius: 200 Ionization Energy: 9,7524 Electrone Gativity: 2,55 Covalenz Radius: 117 Discovery Year: 1826 Human Body: traces Inventor: Ramsay, Sir William & … Selenium belongs to Group 6 (Group VIA) of the periodic table, located between sulfur and tellurium, The color of amorphous selenium is either red (in powder form) or black (in vitreous form). Owing to the stronger met allic properties of selenium as compared to those of sulfur , the C e Se bond is more easily broken by halogens and oxidizing agents than is the C e S bond. In chemical activity and physical properties it resembles sulfur and tellurium.Selenium appearsin a number of allotropic forms: the most popular are a red amorphous powder, a red crystalline material, and a gray crystalline metallike form called metallic selenium. Selenium is a photoconductor, which means it has the ability to change light energy into electrical energy. Selenium. Selenium is a non-metal and is sometimes considered as a metalloid. Find information on Selenium including chemical element properties like atomic weight and a list of compounds that contain Selenium. Selenium can be prepared with either an amorphous or a crystalline structure. Comprehensive data on the chemical element Selenium is provided on this page; including scores of properties, element names in many languages, most known nuclides of Selenium. Selenium. Selenium compounds typically exist in the oxidation states â  2, +2, +4, and +6. Selenium dioxide. Selenium has antioxidant properties and may help protect cells from damage. Physical Characteristics. There are various allotropic forms of selenium, that interconvert into each other with varying temperature. Common chemical compounds are also provided for many elements. Selenium dioxide. Indeed, the toxicity level of selenium to humans was established only 20 years ago by studies of Chinese victims of selenium poisoning, selenosis, who grew corn on selenium rich coal rocks. In the human body, selenium content ranges between 13-20 milligram [4]. 4.2 physical and chemical properties Selenium is a non-metal element with atomic number 34 and an atomic mass of 78.96 (Lide 2000).