"named mendelevium in honor of D.I. Mendeleev, the first to arrange the elements in a periodic manner. Most recently, the synthesis of element 118 (since named oganesson) was reported in October 2006, and the synthesis of element 117 (tennessine) was reported in April 2010. Ten materials familiar to various prehistoric cultures are now known to be chemical elements: Carbon, copper, gold, iron, lead, mercury, silver, sulfur, tin, and zinc. Three additional materials now accepted as elements, arsenic, antimony, and bismuth, were recognized as distinct substances prior to 1500 AD. Phosphorus, cobalt, and platinum were isolated before 1750. Most of the"
"Arsenic Arsenic is a chemical element with symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but only the gray form, which has a metallic appearance, is important to industry. The primary use of arsenic is in alloys of lead (for example, in car batteries and ammunition). Arsenic is a common n-type dopant in semiconductor electronic devices, and the optoelectronic compound gallium arsenide is the second most commonly used semiconductor after doped silicon. Arsenic and its"
"weapon's fallout for several hours. Such a weapon is not known to have ever been built, tested, or used. Isotopes of arsenic Arsenic (As) has 33 known isotopes and at least 10 isomers. Only one of these isotopes, As, is stable; as such, it is considered a monoisotopic element. The longest-lived radioisotope is As has a half-life of 80 days. Arsenic has been proposed as a ""salting"" material for nuclear weapons (cobalt is another, better-known salting material). A jacket of As, irradiated by the intense highenergy neutron flux from an exploding thermonuclear weapon, would transmute into the radioactive isotope As"
"Hassium Hassium is a synthetic chemical element with symbol Hs and atomic number 108. It is named after the German state of Hesse. It is a synthetic element and radioactive; the most stable known isotope, Hs, has a half-life of approximately 10 seconds. In the periodic table of the elements, it is a d-block transactinide element. Hassium is a member of the 7th period and belongs to the group 8 elements: it is thus the sixth member of the 6d series of transition metals. Chemistry experiments have confirmed that hassium behaves as the heavier homologue to osmium in group 8."
"red and white phosphorus were designated by the United States Drug Enforcement Administration as List I precursor chemicals under 21 CFR 1310.02 effective on November 17, 2001. In the United States, handlers of red or white phosphorus are subject to stringent regulatory controls. Phosphorus Phosphorus is a chemical element with symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Earth. It has a concentration in the Earth's crust of about one gram per kilogram (compare copper"
"Isotopes of arsenic Arsenic (As) has 33 known isotopes and at least 10 isomers. Only one of these isotopes, As, is stable; as such, it is considered a monoisotopic element. The longest-lived radioisotope is As has a half-life of 80 days. Arsenic has been proposed as a ""salting"" material for nuclear weapons (cobalt is another, better-known salting material). A jacket of As, irradiated by the intense highenergy neutron flux from an exploding thermonuclear weapon, would transmute into the radioactive isotope As with a half-life of 1.0778 days and produce approximately 1.13 MeV gamma radiation, significantly increasing the radioactivity of the"
"Magnesium Magnesium is a chemical element with symbol Mg and atomic number 12. It is a shiny gray solid which bears a close physical resemblance to the other five elements in the second column (group 2, or alkaline earth metals) of the periodic table: all group 2 elements have the same electron configuration in the outer electron shell and a similar crystal structure. Magnesium is the ninth most abundant element in the universe. It is produced in large, aging stars from the sequential addition of three helium nuclei to a carbon nucleus. When such stars explode as supernovas, much of"
"8 additional days. However the USA's Agency for Toxic Substances and Disease Registry (ATSDR) states that the long-term effects of arsenic exposure cannot be predicted. Blood, urine, hair, and nails may be tested for arsenic; however, these tests cannot foresee possible health outcomes from the exposure. Long-term exposure and consequent excretion through urine has been linked to bladder and kidney cancer in addition to cancer of the liver, prostate, skin, lungs, and nasal cavity. Arsenic Arsenic is a chemical element with symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but"
"fats, and aromatic esters, carotenoids and terpenes. With nitrogen it forms alkaloids, and with the addition of sulfur also it forms antibiotics, amino acids, and rubber products. With the addition of phosphorus to these other elements, it forms DNA and RNA, the chemical-code carriers of life, and adenosine triphosphate (ATP), the most important energy-transfer molecule in all living cells. Nitrogen is the chemical element with atomic number 7, the symbol N and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere. The element"
"Osmium Osmium (from Greek ὀσμή ""osme"", ""smell"") is a chemical element with symbol Os and atomic number 76. It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a trace element in alloys, mostly in platinum ores. Osmium is the densest naturally occurring element, with an experimentally measured (using x-ray crystallography) density of . Manufacturers use its alloys with platinum, iridium, and other platinum-group metals to make fountain pen nib tipping, electrical contacts, and in other applications that require extreme durability and hardness. The element's abundance in the Earth's crust is among the rarest."
"Arsenic trisulfide Arsenic trisulfide is the inorganic compound with the formula AsS. It is a bright yellow solid that is insoluble in water. It also occurs as the mineral orpiment (Latin: auripigment), which has been used as a pigment called King's yellow. It is produced in the analysis of arsenic compounds. It is a group V/VI, intrinsic p-type semiconductor and exhibits photo-induced phase-change properties. The other principal arsenic sulfide is AsS, a red-orange solid known as the mineral realgar. AsS occurs both in crystalline and amorphous forms. Both forms feature polymeric structures consisting of trigonal pyramidal As(III) centres linked by"
"(not avgas), and laboratory cultures can degrade aluminium. However, these life forms do not directly attack or consume the aluminium; rather, the metal is corroded by microbe waste products. Aluminium Aluminium or aluminum is a chemical element with symbol Al and atomic number 13. It is a silvery-white, soft, nonmagnetic and ductile metal in the boron group. By mass, aluminium makes up about 8% of the Earth's crust; it is the third most abundant element after oxygen and silicon and the most abundant metal in the crust, though it is less common in the mantle below. The chief ore of"
"Sulfur Sulfur or sulphur is a chemical element with symbol S and atomic number 16. It is abundant, multivalent, and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula S. Elemental sulfur is a bright yellow crystalline solid at room temperature. Chemically, sulfur reacts with all elements except for gold, platinum, iridium, tellurium, and the noble gases. Sulfur is the tenth most common element by mass in the universe, and the fifth most common on Earth. Though sometimes found in pure, native form, sulfur on Earth usually occurs as sulfide and sulfate minerals. Being abundant"
"element with the symbol Po and atomic number 84, discovered in 1898 by Marie Skłodowska-Curie and Pierre Curie. A rare and highly radioactive element, polonium is chemically similar to bismuth and tellurium, and it occurs in uraniumores. Polonium has been studied for possible use in heating spacecraft. As it is unstable, all isotopes of polonium are radioactive. There is disagreement as to whether polonium is a post-transition metal or metalloid. Astatine is a radioactive chemical element with the symbol At and atomic number 85. It occurs on the Earth only as the result of decay of heavier elements, and decays"
"of metals. Cu comes from Cuprum, Fe comes from Ferrum, Ag from Argentum. The symbols were not followed by a period (full stop) as with abbreviations. Later chemical elements were also assigned unique chemical symbols, based on the name of the element, but not necessarily in English. For example, sodium has the chemical symbol 'Na' after the Latin ""natrium"". The same applies to ""W"" (wolfram) for tungsten, ""Fe"" (ferrum) for iron, ""Hg"" (hydrargyrum) for mercury, ""Sn"" (stannum) for tin, ""K"" (kalium) for potassium, ""Au"" (aurum) for gold, ""Ag"" (argentum) for silver, ""Pb"" (plumbum) for lead, ""Cu"" (cuprum) for copper, and"
"Phosphorus Phosphorus is a chemical element with symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Earth. It has a concentration in the Earth's crust of about one gram per kilogram (compare copper at about 0.06 grams). With few exceptions, minerals containing phosphorus are in the maximally oxidized state as inorganic phosphate rocks. Elemental phosphorus was first isolated (as white phosphorus) in 1669 and emitted a faint glow when exposed to oxygen – hence the name,"
"Einsteinium Einsteinium is a synthetic element with symbol Es and atomic number 99. A member of the actinide series, it is the seventh transuranic element. Einsteinium was discovered as a component of the debris of the first hydrogen bomb explosion in 1952, and named after Albert Einstein. Its most common isotope einsteinium-253 (half-life 20.47 days) is produced artificially from decay of californium-253 in a few dedicated high-power nuclear reactors with a total yield on the order of one milligram per year. The reactor synthesis is followed by a complex process of separating einsteinium-253 from other actinides and products of their"
"Sodium Sodium is a chemical element with symbol Na (from Latin ""natrium"") and atomic number 11. It is a soft, silvery-white, highly reactive metal. 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 ion—the Na cation. Its only stable isotope is Na. The free metal does not occur in nature, but must be prepared from compounds. Sodium is the sixth most abundant element in the Earth's crust and exists in numerous minerals such as feldspars, sodalite, and rock"
"3. Both orpiment and realgar, as well as AsS, have selenium analogs; the analogous AsTe is known as the mineral kalgoorlieite, and the anion AsTe is known as a ligand in cobalt complexes. All trihalides of arsenic(III) are well known except the astatide, which is unknown. Arsenic pentafluoride (AsF) is the only important pentahalide, reflecting the lower stability of the +5 oxidation state; even so, it is a very strong fluorinating and oxidizing agent. (The pentachloride is stable only below −50 °C, at which temperature it decomposes to the trichloride, releasing chlorine gas.) Arsenic is used as the group 5"
"Calcium Calcium is a chemical element with symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossilised remnants of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The"
"or an electrophile; similarly ""Nu"" denotes a nucleophile. ""L"" is used to represent a general ligand in inorganic and organometallic chemistry. ""M"" is also often used in place of a general metal. At least two additional, two-letter generic chemical symbols are also in informal usage, ""Ln"" for any lanthanide element and ""An"" for any actinide element. ""Rg"" was formerly used for any rare gas element, but the group of rare gases has now been renamed noble gases and the symbol ""Rg"" has now been assigned to the element roentgenium. Isotopes are distinguished by the atomic mass number (total protons and"
"Asparagine Asparagine (symbol Asn or N), is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −COO form under biological conditions), and a side chain carboxamide, classifying it as a polar (at physiological pH), aliphatic amino acid. It is non-essential in humans, meaning the body can synthesize it. It is encoded by the codons AAU and AAC. A reaction between asparagine and reducing sugars or other source of carbonyls produces acrylamide in food when"
"Zirconium Zirconium is a chemical element with symbol Zr and atomic number 40. The name ""zirconium"" is taken from the name of the mineral zircon (the word is related to Persian ""zargun"" (zircon;""zar-gun"", ""gold-like"" or ""as gold"")), the most important source of zirconium. It is a lustrous, grey-white, strong transition metal that closely resembles hafnium and, to a lesser extent, titanium. Zirconium is mainly used as a refractory and opacifier, although small amounts are used as an alloying agent for its strong resistance to corrosion. Zirconium forms a variety of inorganic and organometallic compounds such as zirconium dioxide and zirconocene"
"the most common. It is released as a product of U, mainly in nuclear plants and during nuclear weapons tests in the 1950s and 1960s. It has a very long half-life (1.53 million years), its decay emits only low energy radiations, and it is not considered as highly hazardous. Zirconium Zirconium is a chemical element with symbol Zr and atomic number 40. The name ""zirconium"" is taken from the name of the mineral zircon (the word is related to Persian ""zargun"" (zircon;""zar-gun"", ""gold-like"" or ""as gold"")), the most important source of zirconium. It is a lustrous, grey-white, strong transition metal"
"Ammonium iron(III) sulfate Ammonium iron(III) sulfate, NHFe(SO)·12 HO, or NH[Fe(HO)](SO)·6 HO, also known as ferric ammonium sulfate (FAS) or iron alum, is a double salt in the class of alums, which consists of compounds with the general formula AB(SO) · 12 HO. It has the appearance of weakly violet, octahedrical crystals. There has been some discussion regarding the origin of the crystals' colour, with some ascribing it to impurities in the compound, and others claiming it to be a property of the crystal itself. FAS is paramagnetic, acidic and toxic towards microorganisms. It is a weak oxidizing agent, capable of"
"Pararealgar Pararealgar is an arsenic sulfide mineral with the chemical formula AsS also represented as AsS. It forms gradually from realgar under exposure to light. Its name derives from the fact that its elemental composition is identical to realgar, AsS. It is soft with a Mohs hardness of 1 - 1.5, is yellow orange in colour, and its monoclinic prismatic crystals are very brittle, easily crumbling to powder. It is one of the sulfides of arsenic and is one of two isomers of AsS. It forms upon exposure of the symmetrical isomer to light. Its name derives from the fact"
"oxide and siliceous beryllium (ASTM D7458). Beryllium Beryllium is a chemical element with symbol Be and atomic number 4. It is a relatively rare element in the universe, usually occurring as a product of the spallation of larger atomic nuclei that have collided with cosmic rays. Within the cores of stars beryllium is depleted as it is fused and creates larger elements. It is a divalent element which occurs naturally only in combination with other elements in minerals. Notable gemstones which contain beryllium include beryl (aquamarine, emerald) and chrysoberyl. As a free element it is a steel-gray, strong, lightweight and"
"lethal within three weeks; smaller amounts may cause infertility and cancer. The International Atomic Energy Agency and other sources have warned that radioactive materials, such as caesium-137, could be used in radiological dispersion devices, or ""dirty bombs"". Caesium Caesium (IUPAC spelling) or cesium (American spelling) is a chemical element with symbol Cs and atomic number 55. It is a soft, silvery-gold alkali metal with a melting point of 28.5 °C (83.3 °F), which makes it one of only five elemental metals that are liquid at or near room temperature. Caesium has physical and chemical properties similar to those of rubidium"
"Caesium Caesium (IUPAC spelling) or cesium (American spelling) is a chemical element with symbol Cs and atomic number 55. It is a soft, silvery-gold alkali metal with a melting point of 28.5 °C (83.3 °F), which makes it one of only five elemental metals that are liquid at or near room temperature. Caesium has physical and chemical properties similar to those of rubidium and potassium. The most reactive of all metals, it is pyrophoric and reacts with water even at −116 °C (−177 °F). It is the least electronegative element, with a value of 0.79 on the Pauling scale. It"
"Aluminium Aluminium or aluminum is a chemical element with symbol Al and atomic number 13. It is a silvery-white, soft, nonmagnetic and ductile metal in the boron group. By mass, aluminium makes up about 8% of the Earth's crust; it is the third most abundant element after oxygen and silicon and the most abundant metal in the crust, though it is less common in the mantle below. The chief ore of aluminium is bauxite. Aluminium metal is so chemically reactive that native specimens are rare and limited to extreme reducing environments. Instead, it is found combined in over 270 different"
"Arsenic acid Arsenic acid is the chemical compound with the formula HAsO. More descriptively written as AsO(OH), this colorless acid is the arsenic analogue of phosphoric acid. Arsenate and phosphate salts behave very similarly. Arsenic acid as such has not been isolated, but is only found in solution, where it is largely ionized. Its hemihydrate form (HAsO·HO) does form stable crystals. Crystalline samples dehydrate with condensation at 100 °C. It is a tetrahedral species of idealized symmetry ""C"" with As–O bond lengths ranging from 1.66 to 1.71 Å. Being a triprotic acid, its acidity is described by three equilibria: These"
"arsenate, acidic copper arsenate), calcium arsenate, and lead hydrogen arsenate. These three have been used as agricultural insecticides and poisons. The protonation steps between the arsenate and arsenic acid are similar to those between phosphate and phosphoric acid. Unlike phosphorous acid, arsenous acid is genuinely tribasic, with the formula As(OH). A broad variety of sulfur compounds of arsenic are known. Orpiment (AsS) and realgar (AsS) are somewhat abundant and were formerly used as painting pigments. In AsS, arsenic has a formal oxidation state of +2 in AsS which features As-As bonds so that the total covalency of As is still"
"sodium acetate, and EtOAc for ethyl acetate. The pseudoelement symbol ""Ac"" is also sometimes encountered in chemical formulas as indicating the entire acetate ion (CHCO), or the acetyl group (CHCO). It is not to be confused with the symbol of actinium, the first element of the actinide series; context guides disambiguation. For example, the formula for sodium acetate might be abbreviated as ""NaAc"", rather than ""NaCHO"". Care should also be taken to avoid confusion with peracetic acid when using the OAc abbreviation; for clarity and to avoid errors when translated, HOAc should be avoided in literature mentioning both compounds. Although"