Is mark weinstein related to Harvey Weinstein? Reproduction of mallard ducks is impaired at dietary concentrations of 7 ug Se/L. SURVEY . Because of its similarity to tellurium, named for the Earth, Berzelius named the new element after the Moon.[26][27]. The recoding mechanism was worked out first in bacteria and then in mammals (see SECIS element).[40]. Tags: Question 7 . SURVEY . This shows selenium is more likely to be a non-metal, just like sulphur. 2. Marcin. However, it can damage plants at higher doses. Selenium rectifiers were first used in 1933. Is Selenium A Metalloid. Zinc selenide was the first material for blue LEDs, but gallium nitride dominates that market. These findings suggest that, with the exception of vertebrates, aquatic life supports selenium use, whereas terrestrial habitats lead to reduced use of this trace element. 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. The melting/ boiling point of selenium is closer to that of sulphur (a non-metal), compared with metals and metalloids. The selenocysteine-containing form occurs in species as diverse as green algae, diatoms, sea urchins, fish, and chickens. 1. Which element is a metalloid? Many benthic invertebrates can tolerate selenium concentrations up to 300 Î¼g/L of Se in their diet.[79]. [136] Ruminants grazing certain forages, e.g., some white clover varieties containing cyanogenic glycosides, may have higher selenium requirements,[136] presumably because cyanide is released from the aglycone by glucosidase activity in the rumen[137] and glutathione peroxidases is deactivated by the cyanide acting on the glutathione moiety. It is recommended that a water concentration of 2 Î¼g Se/L be considered highly hazardous to sensitive fish and aquatic birds. Anonymous. Iodine can also be named as metalloid. In these compounds, selenium plays a role analogous to that of sulfur. National Research Council, Subcommittee on Sheep Nutrition (1985). [98] Marine organisms retained and sometimes expanded their selenoproteomes, whereas the selenoproteomes of some terrestrial organisms were reduced or completely lost. Metalloid, in chemistry, an imprecise term used to describe a chemical element that forms a simple substance having properties intermediate between those of a typical metal and a typical nonmetal. All of the following statements about different elements are true EXCEPT: A) the element "sodium" is located in the "alkali metals" group of the Periodic table B) Manganese is a transition metal C) Barium is an alkaline earth metal D) Krypton is a noble gas E) Selenium is considered a metalloid **** I wrote down E, is this correct? Common production from the residue then begins by oxidation with sodium carbonate to produce selenium dioxide, which is mixed with water and acidified to form selenous acid (oxidation step). Tags: Question 8 . For salmon, the optimal concentration of selenium is about 1 microgram selenium per gram of whole body weight. Selenium (Se³â´â‚‡â‚‰) is a metalloid which is close to sulfur (S) in terms of properties. The key difference between selenium and tellurium is that selenium is a non-metal, whereas tellurium is a metalloid. How long will the footprints on the moon last? [49][50] Since its invention, solvent extraction and electrowinning (SX/EW) production of copper produces an increasing share of the worldwide copper supply. Their use continued into the 1990s. Se compounds confer a red color to glass. 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. Relevance. [55] Its photovoltaic and photoconductive properties are still useful in photocopying,[67][68][69][70] photocells, light meters and solar cells. This phenomenon was used in the design of light meters and similar devices. nonmetal. Selenium poisoning can be passed from parents to offspring through the egg, and selenium poisoning may persist for many generations. The pyrite from the Falun Mine created a red precipitate in the lead chambers which was presumed to be an arsenic compound, so the pyrite's use to make acid was discontinued. Tellurium is a metalloid and selenium is also sometimes considered as a metalloid, but it is actually a non-metal. [82] There are, however, a few species that have been seen to survive these events and tolerate the increased selenium. Signs and symptoms of selenosis include a garlic odor on the breath, gastrointestinal disorders, hair loss, sloughing of nails, fatigue, irritability, and neurological damage. Selenium transmits an electric current proportional to the amount of light falling on its surface. 4 years ago. Selenium is however commonly described as a metalloid in the environmental chemistry literature. [88], Increased dietary selenium reduces the effects of mercury toxicity,[89][90][91] although it is effective only at low to modest doses of mercury. Inorganic selenium bioaccumulates more readily in phytoplankton than zooplankton. selenium (such as carbon, phosphorus and iodine) is considered In 1954, the first hints of specific biological functions of selenium were discovered in microorganisms by biochemist, Jane Pinsent. Berzelius and Gahn wanted to use the pyrite and they also observed that the red precipitate gave off a smell like horseradish when burned. In plants, it occurs as a bystander mineral[clarification needed], sometimes in toxic proportions in forage (some plants may accumulate selenium as a defense against being eaten by animals, but other plants, such as locoweed, require selenium, and their growth indicates the presence of selenium in soil). Sheets of amorphous selenium convert X-ray images to patterns of charge in xeroradiography and in solid-state, flat-panel X-ray cameras. The Se concentration in soil varies with type, texture and organic matter content of the soil and with rainfall. Polonium. Extreme cases of selenosis can exhibit cirrhosis of the liver, pulmonary edema, or death. [44][45], Certain soils are selenium-rich, and selenium can be bioconcentrated by some plants. also. Selenium pollution is impacting oceans across the world and is mainly caused by anthropogenic factors such as farming runoff and industrial processes. China is the dominant consumer of selenium at 1,500–2,000 tonnes/year. How is Selenium classified? [139], It has been suggested that selenium supplementation may help prevent cancer incidence in people, but research has established there is no evidence to support such claims. For other applications, a red color may be desired, produced by mixtures of CdSe and CdS. Bernd E. Langner "Selenium and Selenium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. answer choices . The consumption in 2010 was divided as follows: metallurgy – 30%, glass manufacturing – 30%, agriculture – 10%, chemicals and pigments – 10%, and electronics – 10%. Silicon is a metalloid meanind it both metal and nonmetal. Se, C and P have very similar metallic Answer Save. Chemistry. [42][43], In living systems, selenium is found in the amino acids selenomethionine, selenocysteine, and methylselenocysteine. Both organic and inorganic forms of selenium are largely converted to monosaccharide conjugates (selenosugars) in the body prior to elimination in the urine. In soils, selenium most often occurs in soluble forms such as selenate (analogous to sulfate), which are leached into rivers very easily by runoff. Selenium is a chemical element with the symbol Se and atomic number 34. Are able to extract electrons from iodides, and Yumiko Yamashita, CS1 maint multiple! 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