Tell about silicon in English

Silicon is the most abundant element found in the Earth’s crust. It is a bluish-grey metalloid which has a metallic luster and is very brittle. It crystallizes in the diamond lattice, has a specific gravity of 2.42 (two point four two), melts at 1, 420 (degrees Centigrade) and boils at 3, 500 .It has an atomic weight of 28. The element is usually tetravalent in its compounds. It forms a great variety of inorganic and organic compounds.

Elementary silicon is used as an alloying constituent to strengthen aluminium, magnesium, copper and other metals. It also has a deoxidizing effect on steel, and in much larger proportions it also confers chemical inertness on ferrous alloys. High-purity silicon is used as the starting material for silicone resins, oil sand in semiconductor devices, such as rectifiers, transistors and solar batteries.

Silicon dioxide, besides its use in tremendous quantities in the ceramic industries, is used as the raw material for making elementary silicon and for silicon carbide. Crystals of silicon carbide are used for piezoelectric devices. Fused quartz sand becomes silica glass, which is used in chemical laboratories and plants as well as an electric insulator.

Silicon forms useful and important compounds with hydrogen, carbon, the halogen elements, nitrogen, oxygen, and sulphur. In addition, useful organosilicon derivatives have been prepared.

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Phosphorus is a chemical element with symbol P and atomic number 15. As an element, phosphorus exists in two major forms—white phosphorus and red phosphorus—but due to its high reactivity, phosphorus is never found as a free element on Earth. Instead phosphorus-containing minerals are almost always present in their maximally oxidised state, as inorganic phosphate rocks. Phosphorus exists as several forms (allotropes) that exhibit strikingly different properties.[9] The two most common allotropes are white phosphorus and red phosphorus. Another form, scarlet phosphorus, is obtained by allowing a solution of white phosphorus in carbon disulfide to evaporate in sunlight. Black phosphorus is obtained by heating white phosphorus under high pressures (about 12, 000 standard atmospheres or 1.2 gigapascals). In appearance, properties, and structure, it resembles graphite, being black and flaky, a conductor of electricity, and has puckered sheets of linked atoms. Another allotrope isdiphosphorus; it contains a phosphorus dimer as a structural unit and is highly reactive.

59) Sulfur or sulphur (see spelling differences) is a chemical element with symbol S and atomic number 16. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S₈. Elemental sulfur is a bright yellow crystalline solid when at room temperature. Chemically, sulfur can react as either an oxidant or a reducing agent. It oxidizes most metals and several nonmetals, including carbon, which leads to its negative charge in most organosulfur compounds, but it reduces several strong oxidants, such as oxygen and fluorine. Chemical properties.Sulfur burns with a blue flame concomitant with formation of sulfur dioxide, notable for its peculiar suffocating odor. Sulfur is insoluble in water but soluble in carbon disulfide and, to a lesser extent, in other nonpolar organic solvents, such as benzene and toluene. The first and the second ionization energies of sulfur are 999.6 and 2252 kJ·mol^{− 1}, respectively. Despite such figures, the +2 oxidation state is rare, with +4 and +6 being more common. The fourth and sixth ionization energies are 4556 and 8495.8 kJ·mol^{− 1}, the magnitude of the figures caused by electron transfer between orbitals; these states are only stable with strong oxidants as fluorine, oxygen, and chlorine.

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Fluorine is a chemical element with symbol F and atomic number 9. It is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. As the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.

Characteristics. Fluorine atoms have nine electrons, one fewer than neon, and electron configuration 1s²2s²2p⁵. F₂ is a corrosive pale yellow or brown gas that a powerful oxidizing agent.

61) Chlorine is a chemical element with symbol Cl and atomic number 17. Chlorine is in the halogen group (17) and is the second lightest halogen following fluorine. The element is a yellow-green gas under standard conditions, where it forms diatomic molecules. Chlorine has the highest electron affinity and the third highest electronegativity of all the reactive elements. For this reason, chlorine is a strong oxidizing agent. Free chlorine is rare on Earth, and is usually a result of direct or indirect oxidation byoxygen. Chemical characteristics[edit]

Along with fluorine, bromine, iodine, and astatine, chlorine is a member of the halogen series that forms the group 17 (formerly VII, VIIA, or VIIB) of the periodic table. Chlorine forms compounds with almost all of the elements to give compounds that are usually called chlorides. Chlorine gas reacts with most organic compounds, and will even sluggishly support the combustion of hydrocarbons.

62 surak Bromine (from Greek: β ρ ῶ μ ο ς, bró mos, meaning " strong-smelling" or " stench")^[5] is a chemical element with symbol Br, and atomic number 35. It is a halogen. The element was isolated independently by two chemists, Carl Jacob Lö wig and Antoine Jerome Balard, in 1825–1826. Elemental bromine is a fuming red-brown liquid at room temperature, corrosive and toxic, with properties between those of chlorine and iodine. Free bromine does not occur in nature, but occurs as colorless soluble crystalline mineral halide salts, analogous to table salt. The element bromine exists as a diatomic molecule, Br₂. It is a dense, mobile, slightly transparent reddish-brown liquid, that evaporates easily at standard temperature and pressures to give an orange vapor (its color resembles nitrogen dioxide) that has a strongly disagreeable odor resembling that of chlorine. It is one of only two elements on the periodic table that are known to be liquids at room temperature (mercury is the other, althoughcaesium, gallium, and rubidium melt just above room temperature).

63 Iodine is a chemical element with symbol I and atomic number 53. The name is from Greek ἰ ο ε ι δ ή ς ioeidē s, meaning violet or purple, due to the color of elemental iodine vapor.^[3]

Iodine and its compounds are primarily used in nutrition, and industrially in the production of acetic acid and certain polymers. Iodine's relatively high atomic number, low toxicity, and ease of attachment to organic compounds have made it a part of many X-ray contrast materials in modern medicine. Iodine has only one stable isotope. A number of iodine radioisotopes, such as ¹³¹I, are also used in medical applications.

Iodine is found on Earth mainly as the highly water-soluble iodide ion I⁻ , which concentrates it in oceans and brine pools. Like the other halogens, free iodine occurs mainly as a diatomic molecule I₂, and then only momentarily after being oxidized from iodide by an oxidant like free oxygen. In the universe and on Earth, iodine's high atomic number makes it a relatively rare element. However, its presence in ocean water has given it a role in biology. It is the heaviest essential element utilized widely by life in biological functions (only tungsten, employed in enzymes by a few species of bacteria, is heavier). Iodine's rarity in many soils, due to initial low abundance as a crust-element, and also leaching of soluble iodide by rainwater, has led to many deficiency problems in land animals and inland human populations. Iodine deficiency affects about two billion people and is the leading preventable cause of intellectual disabilities.^[4]

Iodine is required by higher animals for synthesizing thyroid hormones, which contain the element. Because of this function, radioisotopes of iodine are concentrated in the thyroid gland along with nonradioactive iodine. If inhaled, the radioisotope iodine-131, which has a high fission product yield, concentrates in the thyroid, but is easily remedied with non-radioactive potassium iodide treatment.

Under standard conditions, iodine is a bluish-black solid appearing to sublimate into a noxious violet-pink gas, the colour due to absorption of visible light by electronic transitions between the highest occupied and lowest unoccupied molecular orbitals. Melting at 113.7 °C (236.7 °F), it forms compounds with many elements but is less reactive than the other members of its group, thehalogens, and has some metallic light reflectance.

Of the 37 known (characterized) isotopes of iodine, only one, ¹²⁷I, is stable.

The longest-lived radioisotope, ¹²⁹I, has a half-life of 15.7 million years. This is long enough to make it a permanent fixture of the environment on human time scales, but far too short for it to exist as a primordial isotope today. Instead, iodine-129 is an extinct radionuclide, and its presence in the early Solar System is inferred from the observation of an excess of its daughter xenon-129. This nuclide is also newly made by cosmic rays and as a byproduct of artificial nuclear fission, which it is used to monitor as a very long-lived environmental contaminant.