Is selenium a cation or anion?
The nonmetals arsenic (As), tellurium (Te) and selenium (Se) are also named like the transition metals, and can form either cations or anions. Rule 2: anions. The anion name is formed from the name of the element, but “ide” replaces the normal ending in the elements name. What is the most common selenium ion?
What is the chemical element of selenium?
This article is about the chemical element. For the software testing framework, see Selenium (software). trigonal Selenium is a chemical element with the symbol Se and atomic number 34.
What is the charge of a selenium ion?
What is a selenium ion called? Therefore, the ion of selenium has the charge of 2-. It's known as selenide ion. Click to see full answer.
Is selenium ion similar to halogenium ion?
Selenium ion has similar electrophilicity as halogenium ions. Accordingly, it also can induce the semipinacol rearrangement of allylic alcohols through the same pattern.
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What is the ion for selenium?
Se+4Selenium, ion(4+) | Se+4 - PubChem.
How do you write selenium as an ion?
0:012:35How to Write the Electron Configuration for Selenium (Se and ...YouTubeStart of suggested clipEnd of suggested clipSince se it's not negative or positive it's not an ion. The atomic number the number of protons thatMoreSince se it's not negative or positive it's not an ion. The atomic number the number of protons that'll equal the electrons.
What is the chemical name for selenium?
Seselenium (Se), a chemical element in the oxygen group (Group 16 [VIa] of the periodic table), closely allied in chemical and physical properties with the elements sulfur and tellurium.
Is selenium an isotope or ion?
About Selenium-78 Isotope Selenium 78 Metal (Selenium-78) is a stable (non-radioactive) isotope of Selenium. It is both naturally occurring and produced by fission.
What ion is se?
SelenidePubChem CID107674Molecular FormulaSe-2Synonymsselenide 22541-48-6 selenium(2-) selanediide selenide ion More...Molecular Weight78.97DatesModify 2022-02-12 Create 2004-09-162 more rows
Is bromide ion a cation or anion?
Please visit the Bromine element page for information specific to the chemical element of the periodic table. Bromide is a halide anion and a monoatomic bromine.
How did selenium get its name?
It was Berzelius who discovered selenium in 1817, as an impurity in sulphuric acid. Tellurium had already been discovered, and named after the Greek word for earth, so he named selenium using the Greek word for moon, selene.
What is S element name?
SulfurSulfur - Element information, properties and uses | Periodic Table.
What ion does RB form?
rubidium cation RUBIDIUM IONRubidium ionPubChem CID105153Molecular FormulaRb+Synonymsrubidium cation RUBIDIUM ION rubidium(1+) Rubidium, ion (Rb1+) UNII-PR87B22TGJ More...Molecular Weight85.468DatesModify 2022-02-05 Create 2005-03-272 more rows
What element does MN stand for?
manganesemanganese (Mn), chemical element, one of the silvery white, hard, brittle metals of Group 7 (VIIb) of the periodic table. It was recognized as an element in 1774 by the Swedish chemist Carl Wilhelm Scheele while working with the mineral pyrolusite and was isolated the same year by his associate, Johan Gottlieb Gahn.
What is selenium WebDriver for?
Selenium WebDriver is a web framework that permits you to execute cross-browser tests. This tool is used for automating web-based application testing to verify that it performs expectedly. Selenium WebDriver allows you to choose a programming language to create test scripts.20-May-2021
What is selenium valence electrons?
0:111:29How to Find the Valence Electrons for Selenium (Se) - YouTubeYouTubeStart of suggested clipEnd of suggested clipSo we look for selenium here and it is right here it's in group 16. Sometimes called 6a so it has 6MoreSo we look for selenium here and it is right here it's in group 16. Sometimes called 6a so it has 6 valence electrons.
What is the structure of Selenium?
When rapidly melted, it forms the black, vitreous form, usually sold commercially as beads. The structure of black selenium is irregular and complex and consists of polymeric rings with up to 1000 atoms per ring . Black Se is a brittle, lustrous solid that is slightly soluble in CS 2. Upon heating, it softens at 50 °C and converts to gray selenium at 180 °C; the transformation temperature is reduced by presence of halogens and amines.
Where is Selenium found?
In living systems, selenium is found in the amino acids selenomethionine, selenocysteine, and methylselenocysteine. In these compounds, selenium plays a role analogous to that of sulfur.
What is the most stable isotope of Selenium?
Selenium also has numerous unstable synthetic isotopes ranging from 64 Se to 95 Se; the most stable are 75 Se with a half-life of 119.78 days and 72 Se with a half-life of 8.4 days.
How much selenium is produced in 2011?
Selenous acid is bubbled with sulfur dioxide ( reduction step) to give elemental selenium. 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.
What is the angle of selenium?
The most stable and dense form of selenium is gray and has a hexagonal crystal lattice consisting of helical polymeric chains, where the Se-Se distance is 237.3 pm and Se-Se-Se angle is 130.1° .
How is selenium oxide formed?
Selenium forms two oxides: selenium dioxide (SeO 2) and selenium trioxide (SeO 3 ). Selenium dioxide is formed by the reaction of elemental selenium with oxygen: Structure of the polymer SeO 2: The (pyramidal) Se atoms are yellow. It is a polymeric solid that forms monomeric SeO 2 molecules in the gas phase.
How many isotopes does selenium have?
Selenium has seven naturally occurring isotopes. Five of these, 74 Se, 76 Se, 77 Se, 78 Se, 80 Se, are stable, with 80 Se being the most abundant (49.6% natural abundance). Also naturally occurring is the long-lived primordial radionuclide 82 Se, with a half-life of 9.2×10 19 years. The non-primordial radioisotope 79 Se also occurs in minute quantities in uranium ores as a product of nuclear fission. Selenium also has numerous unstable synthetic isotopes ranging from 64 Se to 95 Se; the most stable are 75 Se with a half-life of 119.78 days and 72 Se with a half-life of 8.4 days. Isotopes lighter than the stable isotopes primarily undergo beta plus decay to isotopes of arsenic, and isotopes heavier than the stable isotopes undergo beta minus decay to isotopes of bromine, with some minor neutron emission branches in the heaviest known isotopes.
What is copper selenide?
Copper selenide is an inorganic binary compound consisting of copper and selenium. It is a p-type semiconductor with a direct bandgap, as well as an indirect bandgap. The bandgap of different metal selenides has been inserted in Table 3. The amount of bandgap of metal selenides is increased with a decrease in particle size. The morphology is the other factor that affects the amount of bandgap. For example, there is a variety of amounts of bandgap in copper selenides. Table 4 shows the effects of the morphology and particle size of the metal selenides on their bandgap.
What is the name of the tandem electrophilic carbon–carbon double bond addition?
Selenium-initiated rearrangement of allylic alcohols sometimes refers to ‘the tandem electrophilic carbon–carbon double-bond addition–Wagner–Meerwein rearrangement,’ 38 in which a carbonium ion rather than an episelenonium ion has been proposed.
What is the metabolite of selenium?
Selenium supplements are typically available in the form of sodium selenite which is metabolized to selenide through either glutathione conjugation and subsequent reduction by glutathione reductase enzymes or reduction by thioredoxin reductases. Selenide is further metabolized to selenocystein by cysteine synthases and to selenophosphate by selenophosphate synthases. Selenide is also metabolized progressively to methyl-selenol, dimethyl selenide, then trimethylselenonium. Selenocysteine is degraded to methyl-selenol, pyruvate and ammonia by cysteine beta lyase. Selenocystein reacts with oxygen to form selenocysteine selenoxide which spontaneously degrades to methylselenic acid, pyruvate and ammonia. Methylselenic acid can be converted to methylselenol via conjugation with thiol groups on proteins like glutathione.
What is the source of selenium?
Electrolytic copper refinery slimes are the principal source of selenium and its sister element, tellurium ... Slimes generated by the refining of primary copper, copper produced from ores and concentrates, generally contain from 5-25% selenium and 2-10% tellurium. ... Some of the first processes to recover selenium on a commercial basis were based on roasting of copper slimes with soda ash to convert both selenium and tellurium to the +6 oxidation state. ... Slimes are intensively mixed with sodium carbonate, a binder such as bentonite, and water to form a stiff paste. The paste is extruded or pelletized and allowed to dry. ... Roasting occurs between temperatures of 530-650 °C. ... Conversion of both elements to the hexavalent form is complete. The roasted pellets or extrudes are ground and leached in water. The hexavalent selenium dissolves as sodium selenate, Na2SeO4. Sodium tellurate, being highly insoluble in the now very strongly alkaline solution, remains in the residue. The separation between selenium and tellurium is readily achieved, provided all tellurium is oxidized to the hexavalent state. ... There are two processes commonly employed for reducing selenium from solution. ... In the first process, employed commercially for may years, selenium is leached from the slimes in the form of the hexavalent sodium selenate. It is recovered from solution by crystallization and the crystalline sodium selenate is mixed with charcoal. Under controlled conditions of heating, the Na2SeO4 is reduced to sodium selenide. The sodium selenide cake is leached with water to form a typically liver-red solution of sodium selenide, which is readily oxidized to the elemental form by blowing air through the solution. ... In the second process, reduction of the hexavalent selenium is accomplished using concentrated hydrochloric acid or ferrous iron salts catalyzed by chloride ions as the reductant.
What is Selenium 75 used for?
Selenium-75, incorporated into the aerosols, was used to determine the Se content in the whole animal, excreta, and individual tissues as a function of time. Virtually all inhaled selenious acid aerosol was rapidly absorbed into the blood from the lungs, gastrointestinal tract, and the nasal membranes.
How long does selenium 75 stay in the body?
Selenium-75 in these organs had a biological half-life of 30 to 40 days. Approximately 50% of the deposited Se was eliminated with a biological half life of 1.2 days.
Where is selenium soluble?
Most selenium compounds are water -soluble and can efficiently be taken up in the intestine. Soluble as well as non-soluble compounds can be taken up by the lungs. When given in excess, selenium compounds are rapidly distributed to major organs of the body. ...
Which element is favored by low pH and reducing conditions?
Elemental selenium is favored by low pH and reducing conditions (1,2); under aerobic conditions, selenium is in the form of the selenite and selenate anions (1). Under acidic conditions, selenite is rapidly reduced to elemental selenium by mild reducing agents (1).
Is Se-methylselenocysteine a selenocompound?
/Experimental Therapy/ ... Se-methylselenocysteine (SeMSC), a naturally occurring organic Se product, is considered as one of the most effective chemopreventive selenocompounds. ... Compared with SeMSC, elemental Se at nano size (Nano-Se) possessed equal efficacy in increasing the activities of glutathione peroxidase, thioredoxin reductase, and glutathione S-transferase, but had much lower toxicity as indicated by median lethal dose, acute liver injury, survival rate, and short-term toxicity. /These/ results suggest that Nano-Se can serve as a potential chemopreventive agent with reduced risk of Se toxicity.
What is the color of selenium?
The color of amorphous selenium is either red (in powder form) or black (in vitreous form). Crystalline monoclinic selenium is a deep red; crystalline hexagonal selenium, the most stable variety, is a metallic gray.
How does selenium conduct electricity?
Selenium's resistance to the flow of electricity is greatly affected by the amount of light shining on it. The brighter the light, the better selenium conducts electricity. This property has made selenium useful in devices that respond to the intensity of light, such as electric eyes, photo cells, light meters for cameras and copiers. Selenium can also produce electricity directly from sunlight and is used in solar cells. Selenium is also a semiconductor and is used in some types of solid-state electronics as well as in rectifiers, devices which convert alternating current electricity into direct current electricity. In addition to its use in electrical devices, selenium is also used to make a ruby-red color in glasses and enamels, as a photographic toner and as an additive to stainless steel.
Why is Selenium called New Window?
New Window. The name derives from the Greek Selene, who was the Greek goddess of the Moon because the element is chemically found with tellurium ( Tellus was the Roman goddess of the Earth). Selenium was discovered by the Swedish chemist Jöns Jacob Berzelius in 1817, while trying to isolate tellurium in an impure sample.
How many isotopes does selenium have?
Naturally selenium contains six stable isotopes. Fifteen other isotopes have been characterized. The element is a member of the sulfur family and resembles sulfur both in its various forms and in its compounds.
What is Selenium used for?
Jefferson Lab, U.S. Department of Energy. Selenium is used in Xerography for reproducing and copying documents, letters, etc. It is used by the glass industry to decolorize glass and to make ruby-colored glasses and enamels. It is also used as a photographic toner, and as an additive to stainless steel.
Is Selenium a stable isotope?
Molecules, atoms, and ions of the stable isotopes of selenium possess slightly different physical and chemical properties , and they commonly will be fractionated during physical, chemical, and biological processes, giving rise to variations in isotopic abundances and in atomic weights.
Is selenium amorphous or crystalline?
Selenium exists in several allotropic forms, although three are generally recognized. Selenium can be prepared with either an amorphous or a crystalline structure. The color of amorphous selenium is either red (in powder form) or black (in vitreous form). Crystalline monoclinic selenium is a deep red; crystalline hexagonal selenium, the most stable variety, is a metallic gray.
Overview
Occurrence
Native (i.e., elemental) selenium is a rare mineral, which does not usually form good crystals, but, when it does, they are steep rhombohedra or tiny acicular (hair-like) crystals. Isolation of selenium is often complicated by the presence of other compounds and elements.
Selenium occurs naturally in a number of inorganic forms, including selenide, s…
Characteristics
Selenium forms several allotropes that interconvert with temperature changes, depending somewhat on the rate of temperature change. When prepared in chemical reactions, selenium is usually an amorphous, brick-red powder. When rapidly melted, it forms the black, vitreous form, usually sold commercially as beads. The structure of black selenium is irregular and complex and consists of
Chemical compounds
Selenium compounds commonly exist in the oxidation states −2, +2, +4, and +6.
Selenium forms two oxides: selenium dioxide (SeO2) and selenium trioxide (SeO3). Selenium dioxide is formed by the reaction of elemental selenium with oxygen:
It is a polymeric solid that forms monomeric SeO2 molecules in the gas phase. …
History
Selenium (Greek σελήνη selene meaning "Moon") was discovered in 1817 by Jöns Jacob Berzelius and Johan Gottlieb Gahn. Both chemists owned a chemistry plant near Gripsholm, Sweden, producing sulfuric acid by the lead chamber process. 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. Berzelius and Gahn wanted to use the pyrite and they also o…
Production
Selenium is most commonly produced from selenide in many sulfide ores, such as those of copper, nickel, or lead. Electrolytic metal refining is particularly productive of selenium as a byproduct, obtained from the anode mud of copper refineries. Another source was the mud from the lead chambers of sulfuric acid plants, a process that is no longer used. Selenium can be refined from these muds by a number of methods. However, most elemental selenium comes as a byproduc…
Applications
Researchers found that application of selenium fertilizer to lettuce crops decreased the accumulation of lead and cadmium. Peaches and pears given a foliar selenium spray contained higher levels of selenium and also stayed firm and ripe longer when in storage. 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. However, it can dama…
Pollution
In high concentrations, selenium acts as an environmental contaminant. Sources of pollution include waste materials from certain mining, agricultural, petrochemical, and industrial manufacturing operations. In Belews Lake North Carolina, 19 species of fish were eliminated from the lake due to 150-200 μg Se/L wastewater discharged from 1974 to 1986 from a Duke Energy coal-fired power plant. At the Kesterson National Wildlife Refuge in California, thousands of fish a…