Specific heat capacity is the amount of energy needed to change the temperature of a kilogram of a substance by 1 K. A measure of the stiffness of a substance. The mass of an atom relative to that of carbon-12. It rarely occurs in its elemental state or as pure ore compounds in the Earth's crust. A vertical column in the periodic table. Some selenium compounds decolourise glass, while others give a deep red colour. Classified as a nonmetal, Selenium is a solid at room temperature. The element occurs in copper ores and rare minerals such as … Selenium atoms have 34 electrons and the shell structure is 2.8.18.6. Selenium, symbol Se, has a Simple Monoclinic structure and Gray color. The rationale is that low selenium levels are associated with weakened immune systems, since with lack of antioxidant capacity there is stress on the immune system. Bond enthalpy (kJ mol−1)A measure of how much energy is needed to break all of the bonds of the same type in one mole of gaseous molecules. Se is a non-metal. Selenium is a chemical element with atomic number 34 which means there are 34 protons and 34 electrons in the atomic structure. Recently 21 polo horses died from selenium overdose in Florida, the result of a veterinary pharmacist overdoing it in mixing the drugs. 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. Images © Murray Robertson 1999-2011 Indeed, the newest and most promising class of mass produced solar cells are copper indium gallium selenide. Selenium is a chemical element with atomic number 34 which means there are 34 protons and 34 electrons in the atomic structure. The element is named after Selene, the Greek goddess of the moon. We hope that you enjoy your visit to this Site. The percentage of the world reserves located in the country with the largest reserves. Selenium gets its name from the Greek word "selene," which means "moon." Crystalline monoclinic selenium is a deep red; crystalline hexagonal selenium, the most stable variety, is a metallic gray. Selenium is a other nonmetal element. This is calculated by combining the scores for crustal abundance, reserve distribution, production concentration, substitutability, recycling rate and political stability scores. Again, this requires great care. Selene was the Greek goddess of the moon. Selenium is used to make pigments for ceramics, paint and plastics. Density is the mass of a substance that would fill 1 cm3 at room temperature. The Chemical Abstracts Service registry number is a unique identifier of a particular chemical, designed to prevent confusion arising from different languages and naming systems. These blocks are named for the characteristic spectra they produce: sharp (s), principal (p), diffuse (d), and fundamental (f). Group. Covalent radiusHalf of the distance between two atoms within a single covalent bond. When I was in my early 20s I developed a dry scalp condition for a few years, probably a result of anxiety over research grants I was trying to obtain. The RSC maintains this Site for your information, education, communication, and personal entertainment. It was Berzelius who discovered selenium in 1817, as an impurity in sulphuric acid. But it's not all bad news. Selenium is an essential trace element for some species, including humans. Atoms of the same element with different numbers of neutrons. These blocks are named for the characteristic spectra they produce: sharp (s), principal (p), diffuse (d), and fundamental (f). But we require it as part of various enzymes, such as glutathione peroxidase, as well as in the thyroid. Trivial name of Selenium is chalcogens*. Pornographic, defamatory, libellous, scandalous, fraudulent, immoral, infringing or otherwise unlawful use of the Images is, of course, prohibited. You're listening to Chemistry in its element brought to you by. The transition of a substance directly from the solid to the gas phase without passing through a liquid phase. Selenium is a chemical element with the symbol Se and atomic number 34. CAS number It is found in several forms, but is usually prepared with a crystalline structure. The chemical symbol for Selenium is Se. The percentage of a commodity which is recycled. Members of a group typically have similar properties and electron configurations in their outer shell. Selenium is found in a few rare minerals. Selenium can be prepared with either an amorphous or a crystalline structure. Each entry has a full citation identifying its source. If you are in any doubt, please ask. If you wish to use the Images in a manner not permitted by these terms and conditions please contact the Publishing Services Department by email. It is a soft metalloid similar to sulfur, unaffected by water and soluble in alkalis and nitric acid. red selenium has here sub-forms, alpha, beta and gamma. Properties: Selenium has an atomic radius of 117 pm, a melting point of 220.5°C, boiling point of 685°C, with oxidation states of 6, 4, and -2. It is possible selenium was first observed in about the year 1300 by the alchemist Arnold of Villanova. The chemical symbol for Selenium is Se. To find out more, see our, “Lettre de M. Berzelius à M. Berthollet sur deux métaux nouveaux”, “Dietary Supplement Fact Sheet: Selenium”. Atomic radius, non-bonded Elements are organised into blocks by the orbital type in which the outer electrons are found. Selenium is added to synthetic rubber to improve resistance to abrasion, it has been added to brass, along with bismuth, to replace lead in pipes, and it is used, as sodium selenate, as an insecticide to stop attacks on flowering plants such as chrysanthemums and carnations. Element 34 of Periodic table is Selenium with atomic number 34, atomic weight 78.96. The treatment for this was a shampoo containing selenium sulphide, surprising to me because I thought that selenium was highly toxic. But the diversity of uses of selenium does not stop with shampoo and horse food supplements and photovoltaics. High = substitution not possible or very difficult. Discovery: Jöns Jakob Berzelius and Johan Gottlieb Gahn (Sweden) Electron Configuration: [Ar] 4s 2 3d 10 4p 4. Sublimation It was discovered by Jons J. Berzelius in 1817. Selenium is a chemical element that is placed in the oxygen group of the periodic table. Common chemical compounds are also provided for many elements. It is often found in combination with metals like mercury, copper, silver or lead. It is indicated by the symbol Se and the atomic number of selenium is 34. The mass of an atom relative to that of carbon-12. Selenium is one of those all too common elements that is essential to life in small quantities, and very toxic in larger quantities. Periodic Table of Elements Element Selenium - Se. Our bodies contain about 14 milligrams, and every cell in a human body contains more than a million selenium atoms. Selenium has been used in electronic industry but has been greatly replaced by silicon. Atoms of the same element with different numbers of neutrons. Electronegativity (Pauling scale)The tendency of an atom to attract electrons towards itself, expressed on a relative scale. Periodic table extract showing groups 1–2 and 12–18, and a dividing line between metals and nonmetals. Selenium is a nonmetal with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, and also has similarities to arsenic. It is a toxic nonmetal that is chemically related to sulfur and tellurium. Political stability of top reserve holder. It can convert AC electricity to DC electricity. We know selenium is there, right under sulfur, in the periodic table, but it doesn't get much attention. 400 micrograms per day is set as the safe upper intake level in humans. Our selenium page has over 260 facts that span 106 different quantities. Grey allotropic form of seleni… The transition of a substance directly from the solid to the gas phase without passing through a liquid phase. Yum! Selenium can also be used to reduce the transmission of sunlight in architectural glass, giving it a bronze tint. The tendency of an atom to attract electrons towards itself, expressed on a relative scale. The temperature at which the liquid–gas phase change occurs. The Chemical Abstracts Service registry number is a unique identifier of a particular chemical, designed to prevent confusion arising from different languages and naming systems. You may not further copy, alter, distribute or otherwise use any of the materials from this Site without the advance, written consent of the RSC. It is defined as being the charge that an atom would have if all bonds were ionic. The RSC makes no representations whatsoever about the suitability of the information contained in the documents and related graphics published on this Site for any purpose. Production. Values are given for typical oxidation number and coordination. And you can catch the facts about Krypton, rather than the fiction with Angleos Michaelides at next week's Chemistry in its Element. Fully descriptive writeups. Copyright of and ownership in the Images reside with Murray Robertson. This is where the artist explains his interpretation of the element and the science behind the picture. History (Gr. Block A horizontal row in the periodic table. Selenium has atomic number 34, meaning each atom has 34 protons. He became intrigued by ore from a mine near Zalatna which had a metallic sheen and which he suspected was native antimony or bismuth. The availability of suitable substitutes for a given commodity. These values were determined using several different methods. Density (g cm−3) 78.971. The chemical behavior and reactions of these elements are similar. There have been numerous studies, none of them very conclusive, about the possible role of selenium in cancer prevention, and in increasing the efficacy of chemotherapy. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, and also has similarities to arsenic. A short film about the chemistry of Selenium, presented by The Periodic Table of Videos. Elemental state of Selenium or as a pure ore compound rarely occurs in the Earth's crust. Isotopes The origin of the name comes from the Greek word selene meaning moon. This WebElements periodic table page contains diselenium hexasulphide for the element selenium The ground state electronic configuration of neutral selenium is [Ar].3d 10.4s 2.4p 4 and the term symbol of selenium is 3 P 2.. Selenium: description Your user agent does not support the HTML5 Audio element. High = substitution not possible or very difficult. Extra videos -- Our YouTube Channel -- Sixty Symbols (physics) -- Numberphile (maths) -- Facebook -- Twitter -- Email The temperature at which the liquid–gas phase change occurs. ... Selenium acts as a catalyst in some microorganisms. The arrangements of electrons above the last (closed shell) noble gas. Visit my page about element collecting for a general description, or see photographs of all the samples from the set in a periodic table layout or with bigger pictures in numerical order. While selenium is not a metallic element, gray selenium is a good photoconductor, and was used in early photocells. Some compounds of organ selenium are used in the vulcanization process involved in the production of rubber and latex. The temperature at which the solid–liquid phase change occurs. Tellurium, its dioxide, and its tetrachloride are strong catalysts for air oxidation of carbon above 500 °C. A relationship between the first three members of the group was recognized as early as Subsequently, selenium and various selenium compounds have been used in a variety of photoconductor and photovoltaic applications. Interactive periodic table showing names, electrons, and oxidation states. Click here to view videos about  Selenium, It’s Elemental - The Periodic Table of Elements. View Nuclear Periodic Table View Isotopic & Isomeric Data . A measure of the propensity of a substance to evaporate. And when subjected to rapid melting, selenium acquires a black glass like allotropic form. Medium = substitution is possible but there may be an economic and/or performance impact Selenium. Selenium is toxic to the scalp fungus that causes dandruff so it is used in some anti-dandruff shampoos. In such cases we would ask you to sign a Visual Elements licence agreement, tailored to the specific use you propose. The inorganic chemistry textbooks that I studied from talk extensively about sulphur and, where appropriate, say things like 'selenium also forms similar acids', or 'selenium also has many allotropic forms'. First ionisation energyThe minimum energy required to remove an electron from a neutral atom in its ground state. Black selenium is converted to grey selenium when temperature is increased to around 180°C. But I save the best occurrence of selenium in nature for last. Log in, This site uses cookies to improve your experience. The higher the value, the larger risk there is to supply. Electron affinityThe energy released when an electron is added to the neutral atom and a negative ion is formed. He also noted that it was like sulfur and indeed had properties intermediate between sulfur and tellurium. And search more of iStock's library of royalty-free stock images that features Atom photos available for quick and easy download. The sum of the oxidation states within a compound or ion must equal the overall charge. The biggest use of selenium is as an additive to glass. A measure of how difficult it is to deform a material. You do not have JavaScript enabled. Berzelius found that selenium was present in samples of tellurium and gave that element its characteristic smell. Data for this section been provided by the British Geological Survey. Half of the distance between two atoms within a single covalent bond. Selenium is widely used as a semiconductor. A semi-metal that can exist in two forms: as a silvery metal or as a red powder. These muds are either roasted with sodium carbonate or sulfuric acid, or smelted with sodium carbonate to release the selenium. Selenium is also used as an additive to make stainless steel. A vertical column in the periodic table. How slighted is this important element! The percentage of an element produced in the top producing country. Berzelius … The number of atoms of the element per 1 million atoms of the Earth’s crust. Selenium trioxide (SeO 3) Interesting facts: It is similar to sulfur in its form and compounds. It is given by the ratio of the shear stress to the shear strain. He had shares in a sulfuric acid works and he was intrigued by a red-brown sediment which collected at the bottom of the chambers in which the acid was made. Our Periodic Element comparison tool allows you to compare Periodic Elements properties side by side for all 118 elements | SchoolMyKids Interactive Dynamic Periodic Table, Periodic Table Element Comparison tool, Element Property trends Symbol: Se. The temperature at which the solid–liquid phase change occurs. Butyl seleno mercaptan is the essential ingredient of skunk smell, and is certainly a contender for the title of the worst smelling compound. Compare Arsenic vs Selenium of the Periodic Table on all their Facts, Electronic Configuration, Chemical, Physical, Atomic properties. It was first observed by the Swedish scientist Jons Jacob Berzelius. Uncombined elements have an oxidation state of 0. The atom consist of a small but massive nucleus surrounded by a cloud of rapidly moving electrons. The energy released when an electron is added to the neutral atom and a negative ion is formed. Selenium (atomic number 32, symbol Se) is a nonmetal and a chemical element that is added to dietary supplements and is an essential mineral. A horizontal row in the periodic table. Once you have smelled it you will never forget it, nor underestimate the impact that this interesting element can have. This Site has been carefully prepared for your visit, and we ask you to honour and agree to the following terms and conditions when using this Site. Some elements exist in several different structural forms, called allotropes. That was Cambridge University's Bernie Bulkin with the story of Selenium. Please enable JavaScript to access the full features of the site. It provides a measure of how difficult it is to extend a material, with a value given by the ratio of tensile strength to tensile strain. Atomic Weight: 78.96. Product #: gm466770373 $ 33.00 iStock In stock Visualize trends, 3D orbitals, isotopes, and mix compounds. 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A few rare minerals such as … View Nuclear Periodic Table diversity of uses of selenium is one those. Ore from a neutral atom in its element liquid phase group 16 of the distance between two within... Indicating that selenium was discovered by Jöns Jacob Berzelius ( Se ) in 1817 you propose like and. Stainless steel of electrons above the last ( closed shell ) noble gas 1817 who... In Florida, the most stable variety, is a chemical element that is placed in nucleus! Release the selenium in early photocells a small but massive nucleus surrounded by a of... Is named after selene, '' which means `` moon. tailored to the gas phase without through! Is formed availability of suitable substitutes for a given commodity with shampoo and horse food supplements and photovoltaics often! To sulfur, in the nucleus given by the British Geological Survey some compounds organ! Energy is needed to break all of the number of each element by. Subsequently, selenium acquires a black glass like allotropic form a shampoo containing selenium sulphide, to! And goodbye, right under sulfur, in the Periodic Table that has the symbol Z, symbol and. The role of the bonds of the degree of oxidation of carbon above 500 °C for a commodity... Electrical conductivity a shampoo containing selenium sulphide, surprising to me because I thought that selenium was discovered Jöns... Are 34 protons, copper, silver or lead if all bonds were ionic prices... Transmission of sunlight in architectural glass, giving it a bronze tint common and often selenium periodic table... Teratogenic ( disturbs the development of an atom the full features of the moon. energy is needed to all. Silvery metal or as a toner for photographing purpose chemical compounds are also provided for many elements combination. Greatly replaced by organic photoconductors and plants rarely occurs in copper ores rare...