Tellurium is chemically related to selenium and sulfur. In nuclear industry boron is commonly used as a neutron absorber due to the high neutron cross-section of isotope 10B. Mendelevium is a metallic radioactive transuranic element in the actinide series, it is the first element that currently cannot be produced in macroscopic quantities. , About 2,000 tonnes of selenium were produced in 2011 worldwide, mostly in Germany (650 t), Japan (630 t), Belgium (200 t), and Russia (140 t), and the total reserves were estimated at 93,000 tonnes. (1969), Discoverer: Scientists at Dubna, Russia (1967)/Lawrence Berkeley Laboratory (1970), Discoverer: Armbruster, Paula and Muenzenberg, Dr. Gottfried, Element Category: unknown, probably a transition metal, Discoverer: David Anderson, Ruhani Rabin, Team Updraft, Element Category: unknown, probably a post-transition metal, Discoverer: Hisinger, Wilhelm and Berzelius, Jöns Jacob/Klaproth, Martin Heinrich. , During the electrowinning of manganese, the addition of selenium dioxide decreases the power necessary to operate the electrolysis cells. Rubidium is a soft, silvery-white metallic element of the alkali metal group, with an atomic mass of 85.4678. Helium is a chemical element with atomic number 2 which means there are 2 protons and 2 electrons in the atomic structure.  Evidence suggests that the molecular mechanisms of mercury toxicity includes the irreversible inhibition of selenoenzymes that are required to prevent and reverse oxidative damage in brain and endocrine tissues.  Hydrogen selenide is an extremely toxic, corrosive gas. , The selenium content in the human body is believed to be in the 13–20 mg range. Terbium is a silvery-white, rare earth metal that is malleable, ductile, and soft enough to be cut with a knife. Discoverer: Scientists at Dubna, Russia (1964)/Albert Ghiorso et. This is a list of chemical elements, sorted by atomic mass (or most stable isotope) and color coded according to type of element.Each element's atomic number, name, element symbol, and group and period numbers on the periodic table are given. A few of these appeared more recently, in the last 50–200 million years, in fruits and flowers of angiosperm plants. Cancer patients receiving daily oral doses of selenothionine may achieve very high plasma and urine selenium concentrations. Manganese is a metal with important industrial metal alloy uses, particularly in stainless steels. Lead has the highest atomic number of any stable element and concludes three major decay chains of heavier elements. This color cancels out the green or yellow tints that arise from iron impurities typical for most glass. Selenium is not produced directly by nuclear fusion. Symbol: Se. Selenium occurs naturally in a number of inorganic forms, including selenide, selenate, and selenite, but these minerals are rare. The name samarium is after the mineral samarskite from which it was isolated.  Also, selenium interacts with other minerals, such as zinc and copper. Selenium is a chemical element with the symbol Se and atomic number 34. Since the density (ρ) of a substance is the total mass (m) of that substance divided by the total volume (V) occupied by that substance, it is obvious, the density of a substance strongly depends on its atomic mass and also on the atomic number density (N; atoms/cm3).  Elemental selenium and most metallic selenides have relatively low toxicities because of low bioavailability.  Both chemists owned a chemistry plant near Gripsholm, Sweden, producing sulfuric acid by the lead chamber process. Atomic mass of Selenium is 78.96 u. Technetium is a chemical element with atomic number 43 which means there are 43 protons and 43 electrons in the atomic structure. It is by mass the most common element on Earth, forming much of Earth’s outer and inner core. Elemental rubidium is highly reactive, with properties similar to those of other alkali metals, including rapid oxidation in air. Very soft and malleable, indium has a melting point higher than sodium and gallium, but lower than lithium and tin. Melting Point: 217.0 °C (490.15 K, 422.6 °F) Boiling Point: 684.9 °C (958.05005 K, 1264.8201 °F) Number of Protons/Electrons: 34. The chemical symbol for Actinium is Ac. Germanium is a lustrous, hard, grayish-white metalloid in the carbon group, chemically similar to its group neighbors tin and silicon. It is the heaviest element that can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic quantities. Gallium does not occur as a free element in nature, but as gallium(III) compounds in trace amounts in zinc ores and in bauxite. The only stable chloride is selenium monochloride (Se2Cl2), which might be better known as selenium(I) chloride; the corresponding bromide is also known. In the human body, selenium content ranges between 1… Californium is a chemical element with atomic number 98 which means there are 98 protons and 98 electrons in the atomic structure. Selenium is listed as an ingredient in many multivitamins and other dietary supplements, as well as in infant formula, and is a component of the antioxidant enzymes glutathione peroxidase and thioredoxin reductase (which indirectly reduce certain oxidized molecules in animals and some plants) as well as in three deiodinase enzymes. National Research Council, Committee on Nutrient Requirements of Small Ruminants (2007). A major development was the discovery that steel could be made highly resistant to corrosion and discoloration by adding metallic chromium to form stainless steel. Connected lines with dots. Selenium rectifiers were first used in 1933. Members of the oxygen family, can combine with most other groups or families on the periodic table, except for inert gases. Curium is a chemical element with atomic number 96 which means there are 96 protons and 96 electrons in the atomic structure. Because of its high chemical reactivity, barium is never found in nature as a free element. Antimony is a lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite. The chemical symbol for Thorium is Th. Commercially, selenium is produced as a byproduct in the refining of these ores, most often during production. The chemical symbol for Curium is Cm. Silicon is a hard and brittle crystalline solid with a blue-grey metallic lustre, it is a tetravalent metalloid and semiconductor. The selenium cell was used in the photophone developed by Alexander Graham Bell in 1879.  This changes the availability of selenium because only a comparably small part of the selenium in the ore is leached with the copper. The chemical symbol for Rhenium is Re. Mass was no longer considered unchangeable in the closed system. , In fish and other wildlife, selenium is necessary for life, but toxic in high doses. They all have relatively low, monoclinic crystal symmetries and contain nearly identical puckered Se8 rings with different arrangements, as in sulfur. It is a soft, silvery-white alkali metal. In low doses, selenium has shown a beneficial effect on plant resistance to various environmental stress factors including drought, UV-B, soil salinity, and cold or hot temperatures.  It has also been suggested that season could have an impact on the harmful effects of selenium on fish. Osmium is the densest naturally occurring element, with a density of 22.59 g/cm3. The chemical symbol for Tellurium is Te. It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity, behind only oxygen and fluorine.  The 1992 study actually found the maximum safe dietary Se intake to be approximately 800 micrograms per day (15 micrograms per kilogram body weight), but suggested 400 micrograms per day to avoid creating an imbalance of nutrients in the diet and to accord with data from other countries. However, the lack of tellurium compounds in the Falun Mine minerals eventually led Berzelius to reanalyze the red precipitate, and in 1818 he wrote a second letter to Marcet describing a newly found element similar to sulfur and tellurium. Being a typical member of the lanthanide series, europium usually assumes the oxidation state +3. The chemical symbol for Zirconium is Zr. Erbium is a chemical element with atomic number 68 which means there are 68 protons and 68 electrons in the atomic structure. 34 electrons (green) bind to the nucleus, successively occupying available electron shells (rings). Another selenium-bearing enzyme in some plants and in animals (thioredoxin reductase) generates reduced thioredoxin, a dithiol that serves as an electron source for peroxidases and also the important reducing enzyme ribonucleotide reductase that makes DNA precursors from RNA precursors. Related terms: Arsenic ; Tellurium; Selenites; Protein; Peroxidase; Glutathione; Annealing; View all Topics. Salts of selenous acid are called selenites. is a rare earth element with a metallic silver luster. Molybdenum a silvery metal with a gray cast, has the sixth-highest melting point of any element. Tungsten is a chemical element with atomic number 74 which means there are 74 protons and 74 electrons in the atomic structure. It is a member of the chalcogen group on the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. It is the fourth most common element in the Earth’s crust. Diagram of the nuclear composition and electron configuration of an atom of selenium-80 (atomic number: 34), the most common isotope of this element. The chemical symbol for Technetium is Tc. σελήνη [selḗnē], Mond) wurde 1817 von Jöns Jakob Berzelius im Bleikammerschlamm einer Schwefelsäurefabrik entdeckt; zuerst hielt Berzelius die Substanz für Tellur (von lateinisch tellus Erde), zu dem Selen einige Ähnlichkeiten aufweist; so entwickelt sich bei der Verbrennung beider Elemente ein ausgeprägter Geruch nach Rettich. The most commonly used spontaneous fission neutron source is the radioactive isotope californium-252. National Research Council, Subcommittee on Sheep Nutrition (1985). The density of Hassium results from its high atomic weight and from the significant decrease in ionic radii of the elements in the lanthanide series, known as lanthanide and actinide contraction. Selenium intensifies and extends the tonal range of black-and-white photographic images and improves the permanence of prints. The chemical symbol for Promethium is Pm. Hafnium is a lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in many zirconium minerals. Selenium as a dietary supplement is available in many forms, including multi-vitamins/mineral supplements, which typically contain 55 or 70 µg/serving. Titanium is a chemical element with atomic number 22 which means there are 22 protons and 22 electrons in the atomic structure. The atomic mass is the mass of an atom. It is the eponym of the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table, of which lanthanum is the first and the prototype. Five of these, 74Se, 76Se, 77Se, 78Se, 80Se, are stable, with 80Se being the most abundant (49.6% natural abundance). Liquid nitrogen (made by distilling liquid air) boils at 77.4 kelvins (−195.8°C) and is used as a coolant. The chemical symbol for Platinum is Pt. Erbium is a silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements. Gallium is a chemical element with atomic number 31 which means there are 31 protons and 31 electrons in the atomic structure. Gold is thought to have been produced in supernova nucleosynthesis, from the collision of neutron stars. Calcium is an alkaline earth metal, it is a reactive pale yellow metal that forms a dark oxide-nitride layer when exposed to air. The chemical symbol for Thallium is Tl. Number of Neutrons: 45. The chemical symbol for Uranium is U. In 1873, Willoughby Smith found that the electrical resistance of grey selenium was dependent on the ambient light. Although classified as a rare earth element, samarium is the 40th most abundant element in the Earth’s crust and is more common than such metals as tin. Units of measure have been defined for mass and energy on the atomic scale to make measurements more convenient to express. Bromine is the third-lightest halogen, and is a fuming red-brown liquid at room temperature that evaporates readily to form a similarly coloured gas. It is a synthetic element (first synthesised at Hasse in Germany) and radioactive. , Selenium reacts with cyanides to yield selenocyanates:, Selenium, especially in the II oxidation state, forms stable bonds to carbon, which are structurally analogous to the corresponding organosulfur compounds. Berkelium is a member of the actinide and transuranium element series. , Selenium interacts with other nutrients, such as iodine and vitamin E. The effect of selenium deficiency on health remains uncertain, particularly in relation to Kashin-Beck disease. Selenium is the chemical in the 16 th group and 4 th period of the periodic table. , Although selenium is an essential trace element, it is toxic if taken in excess. Sources of pollution include waste materials from certain mining, agricultural, petrochemical, and industrial manufacturing operations.  This led to its use as a cell for sensing light. The chemical symbol for Neon is Ne. Carbon is the 15th most abundant element in the Earth’s crust, and the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen.  Elevated dietary methylmercury levels can amplify the harm of selenium toxicity in oviparous species. The various species of atoms whose nuclei contain particular numbers of protons and neutrons are called nuclides. The most probable fission fragment masses are around mass 95 (Krypton) and 137 (Barium). ), Selenium may inhibit Hashimoto's disease, in which the body's own thyroid cells are attacked as foreign. Uranium is a silvery-white metal in the actinide series of the periodic table. For every tonne of manganese, an average 2 kg selenium oxide is used. From Wikipedia, the free encyclopedia Selenium (34 Se) has six natural isotopes that occur …  Since its invention, solvent extraction and electrowinning (SX/EW) production of copper produces an increasing share of the worldwide copper supply. Three days later, a pharmacy released a statement explaining that the horses had received an incorrect dose of one of the ingredients used in a vitamin/mineral supplement compound that had been incorrectly prepared by a compounding pharmacy. Copernicium - Atomic Mass - Atomic Weight - Cn, What is Atomic Mass - Isotopic Mass - Definition, Actinium - Atomic Mass - Atomic Weight - Ac, Polonium - Atomic Mass - Atomic Weight - Po, Antimony - Atomic Mass - Atomic Weight - Sb, Arsenic - Atomic Mass - Atomic Weight - As, Arsenic – Atomic Mass – Atomic Weight – As, Bromine – Atomic Mass – Atomic Weight – Br. In the Se8 rings, the Se-Se distance is 233.5 pm and Se-Se-Se angle is 105.7° . Ruthenium is a chemical element with atomic number 44 which means there are 44 protons and 44 electrons in the atomic structure. Astatine is the rarest naturally occurring element on the Earth’s crust. Atomic Mass of Selenium. Thorium is moderately hard, malleable, and has a high melting point. The chronic toxic dose of selenite for humans is about 2400 to 3000 micrograms of selenium per day. Selenium-specific supplements typically contain either 100 or 200 µg/serving. Especially common are selenides (R2Se, analogues of thioethers), diselenides (R2Se2, analogues of disulfides), and selenols (RSeH, analogues of thiols). The selenide dianion Se2− forms a variety of compounds, including the minerals from which selenium is obtained commercially. The chemical symbol for Iodine is I. Iodine is the heaviest of the stable halogens, it exists as a lustrous, purple-black metallic solid at standard conditions that sublimes readily to form a violet gas. Thulium is an easily workable metal with a bright silvery-gray luster. These elements, along with the chemically similar elements scandium and yttrium, are often collectively known as the rare earth elements. Relative atomic mass: 78.971(8) Selenium was discovered by Jöns Jacob Berzelius (SE) in 1817. , Increased dietary selenium reduces the effects of mercury toxicity, although it is effective only at low to modest doses of mercury. The unit of measure for mass is the atomic mass unit (amu). Discoverer: Corson, Dale R. and Mackenzie, K. R. The actinide or actinoid series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium. Its boiling point is the lowest among all the elements. The total number of neutrons in the nucleus of an atom is called the neutron number of the atom and is given the symbol N. Neutron number plus atomic number equals atomic mass number: N+Z=A. Like all elements with atomic number over 100, nobelium can only be produced in particle accelerators by bombarding lighter elements with charged particles. It is indicated by the symbol Se and the atomic number of selenium is 34. Some of the selenium oxyhalides, such as selenium oxyfluoride (SeOF2) and selenium oxychloride (SeOCl2) have been used as specialty solvents. At 0.099%, phosphorus is the most abundant pnictogen in the Earth’s crust. Rhodium is a rare, silvery-white, hard, corrosion resistant and chemically inert transition metal. The chemical symbol for Ytterbium is Yb. The first alloy used on a large scale was bronze, made of tin and copper, from as early as 3000 BC. Chlorine is a yellow-green gas at room temperature. Like all elements with atomic number over 100, lawrencium can only be produced in particle accelerators by bombarding lighter elements with charged particles. Lanthanoids comprise the 15 metallic chemical elements with atomic numbers 57 through 71, from lanthanum through lutetium.  The structure of black selenium is irregular and complex and consists of polymeric rings with up to 1000 atoms per ring. Cadmium is a soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. The atomic mass or relative isotopic mass refers to the mass of a single particle, and therefore is tied to a certain specific isotope of an element. The glutathione peroxidase family of enzymes (GSH-Px) catalyze certain reactions that remove reactive oxygen species such as hydrogen peroxide and organic hydroperoxides: The thyroid gland and every cell that uses thyroid hormone use selenium, which is a cofactor for the three of the four known types of thyroid hormone deiodinases, which activate and then deactivate various thyroid hormones and their metabolites; the iodothyronine deiodinases are the subfamily of deiodinase enzymes that use selenium as the otherwise rare amino acid selenocysteine. Members of the oxygen family become more active as you move upward on the periodic table. Strontium is a chemical element with atomic number 38 which means there are 38 protons and 38 electrons in the atomic structure. Neptunium metal is silvery and tarnishes when exposed to air. Barium is a chemical element with atomic number 56 which means there are 56 protons and 56 electrons in the atomic structure. The chemical symbol for Terbium is Tb. Selenium also has numerous unstable synthetic isotopes ranging from 64Se to 95Se; the most stable are 75Se with a half-life of 119.78 days and 72Se with a half-life of 8.4 days. However, most elemental selenium comes as a byproduct of refining copper or producing sulfuric acid. Know what is Selenium, Chemical Properties of Selenium, Atomic Mass, and more at BYJU'S 2) You may not distribute or commercially exploit the content, especially on another website. Tellurium is one … The chemical properties of this silvery gray, crystalline transition metal are intermediate between rhenium and manganese. 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. We assume no responsibility for consequences which may arise from the use of information from this website. Thulium is a chemical element with atomic number 69 which means there are 69 protons and 69 electrons in the atomic structure. Sodium is an alkali metal, being in group 1 of the periodic table, because it has a single electron in its outer shell that it readily donates, creating a positively charged atom—the Na+ cation. Signs and symptoms of selenosis include a garlic odor on the breath, gastrointestinal disorders, hair loss, sloughing of nails, fatigue, irritability, and neurological damage. Promethium is one of only two such elements that are followed in the periodic table by elements with stable forms. The chemical symbol for Osmium is Os. Mass numbers of typical isotopes of Selenium are 74; 76; 77; 78; 80. Michiaki Yamashita, Shintaro Imamura, Md. It has an estimated density of 40.7 x 103 kg/m3. Electrolytic metal refining is particularly productive of selenium as a byproduct, obtained from the anode mud of copper refineries. It is recommended that a water concentration of 2 μg Se/L be considered highly hazardous to sensitive fish and aquatic birds. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins. It is the fifth most abundant element in Earth’s crust and the third most abundant metal, after iron and aluminium. Like the other metals of the platinum group, ruthenium is inert to most other chemicals. Representatives of selenides, diselenides, and selenols include respectively selenomethionine, diphenyldiselenide, and benzeneselenol. Berkelium is a chemical element with atomic number 97 which means there are 97 protons and 97 electrons in the atomic structure. The chemical symbol for Cerium is Ce. 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. , Owing to its use as a photoconductor in flat-panel x-ray detectors (see below), the optical properties of amorphous selenium (α-Se) thin films have been the subject of intense research.. The chemical symbol for Molybdenum is Mo. and Gay-Lussac, L.-J. The US Recommended Dietary Allowance (RDA) of selenium for teenagers and adults is 55 µg/day. Samarium is a typical member of the lanthanide series, it is a moderately hard silvery metal that readily oxidizes in air. Selenium burns in air and is toxic by inhalation or ingestion. The atomic mass or relative isotopic mass refers to the mass of a single particle, and therefore is tied to a certain specific isotope of an element. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal. For this purpose, various selenite and selenate salts are added. Other selenium allotropes may contain Se6 or Se7 rings. The demand for selenium by the electronics industry is declining. Lanthanum is a soft, ductile, silvery-white metal that tarnishes rapidly when exposed to air and is soft enough to be cut with a knife.
selenium atomic mass
Dec 5, 2020 | Uncategorized