Silicon atom Silicon and its compounds - Hypermarket of knowledge

The sequence number is 14, the charge of the nucleus is +14, there are 14 protons in the nucleus, 14 electrons. Period number III - 14 electrons move along three energy levels. Group IV number - on the outer energy level there are 4 electrons. The radius of the atom is larger than that of carbon - the ability to release electrons increases. Increases metallic and reducing properties (in comparison with carbon). Si Ge Sn Pb. General characteristics of silicon on the position in the periodic system. C.

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Silicon

"Silicon Lesson" - Carbon dioxide about yourself and humanity. Work in pairs, mutual testing - no errors (5), two errors- (4), etc. 3% in the air - dizziness, tinnitus, drowsiness. 20% is fatal to humans. On the manifestation of non-metallic and metallic properties. Team evaluation. What can be said about the size of the radii of atoms from carbon to lead?

"Silicon and its compounds" - Consider the natural compounds of silicon. Give a general characteristic of the element silicon. Getting silicon. Silicon was first discovered in 1811 by Gay-Lussac and Tenar. The structure and properties of atoms. Silicon oxide unlike carbon monoxide (IV) does not interact with water. Semiconductor. t melt (Si) = 1415? C, t melt (diamond) = 3730? C.

"Silicon isotopes" - Production of polycrystalline silicon. Dependence of the position of the maximum of the Raman band on atomic mass. Burner. Production of monocrystalline seed. Zoned silicon. Protective covering. Thermal conductivity of isotopically enriched silicon-28. Growing single crystals. The distribution of the concentration of isotopes along the length of the seed.

"Silicon Compounds" - Varieties of quartz. Jasper. Getting silicates. Natural silicates. Silicon oxide. Minerals based on SiO2. Chemical properties of SiO2. The discovery of silicon. Silicon and its compounds. Silicon. Agate. Oxidation state Electronic configuration. Silicates and hydrogen. Rhinestone. Being in nature. Silane

"Carbon and silicon" - Chemical properties. One of the softest among solids. Silicate bricks. This mixture is called generator gas. Fig.1 Model of the diamond lattice. The resulting gas consists of free nitrogen and carbon monoxide (II). More than 99% of carbon in the atmosphere is in the form of carbon dioxide. Position in PSCE.

"Silicon" - Until the completion of the external level, silicon lacks 4 electrons. Silicon oxide (IV). General characteristics of silicon on the position in the periodic system. In laboratories, silicon is produced by reducing the silicon oxide SiO2. Physical properties. Silicates - silicic acid salts. Silicate industry.

There are 6 presentations in total.

One of the most sought-after elements in technology and industry is silicon. To this he owes his unusual properties. Today there are a lot of various compounds of this element, which play an important role in the synthesis and creation of technical products, dishes, glass, equipment, building and finishing materials, jewelry and other industries.

General characteristics of silicon

If we consider the position of silicon in the periodic system, we can say this:

1. Located in the IV group of the main subgroup.
2. Sequence number 14.
3. The atomic mass is 28.086.
4. Chemical symbol Si.
5. The name - silicon, or in Latin - silicium.
6. Electronic configuration of the outer layer 4e: 2e: 8e.

The crystal lattice of silicon is similar to a diamond lattice. The atoms are located in the nodes, its type is cubic face-centered. However, due to the greater bond length, the physical properties of silicon are very different from the properties of the allotropic modification of carbon.

Physical and chemical properties

A few more variations of silicon dioxide:

• quartz;
• river and;
• flint;
• feldspars.

The use of silicon in these types is implemented in construction, engineering, electronics, chemical industry, metallurgy. Together, these oxides are a single substance - silica.

Silicon carbide and its application

Silicon and its compounds are materials of the future and the present. One of such materials is carborundum or carbide of this element. The chemical formula of SiC. It occurs in nature in the form of the mineral moissanite.

In its pure form, the compound of carbon and silicon are beautiful transparent crystals that resemble diamond structures. However, for technical purposes, substances painted in green and black are used.

The main characteristics of this substance, allowing its use in metallurgy, engineering, chemical industry, are as follows:

• wide-gap semiconductor;
• very high degree of strength (7 by;
• resistant to high temperatures;
• excellent electrical resistance and thermal conductivity.

All this allows the use of carborundum as an abrasive material in metallurgy and chemical syntheses. And also on its basis to produce a broad-spectrum LEDs, parts for glass melting furnaces, nozzles, torches, jewelry (moissanite is valued above cubic zirconia).

Silane and its value

The hydrogen compound silicon is called silane and cannot be obtained by direct synthesis from the starting materials. To obtain it, silicides of various metals are used, which are treated with acids. As a result, gaseous silane is released and a metal salt is formed.

Interestingly, the compound in question is never formed alone. The reaction always produces a mixture of mono-, di-, and trisilane, in which the silicon atoms are interconnected in chains.

According to their properties, these compounds are strong reducing agents. At the same time, they themselves are easily oxidized by oxygen, sometimes with an explosion. With halogens, reactions are violent always, with a large release of energy.

The silane application fields are as follows:

1. Reactions of organic syntheses, as a result of which important organosilicon compounds are formed - silicones, rubbers, sealants, lubricants, emulsions and others.
2. Microelectronics (liquid crystal monitors, integrated technical circuits, etc.).
3. Getting ultrapure polysilicon.
4. Dentistry during prosthetics.

Thus, the value of silanes in the modern world is high.

Silicic acid and silicates

The hydroxide of the considered element is different silicic acids. Allocate:

• meta;
• ortho;
• polysilicon and other acids.

All of them share common properties - extreme instability in a free state. They easily decompose under the action of temperature. Under normal conditions, there are not for long, turning first into a sol, and then into a gel. After drying, such structures are called silica gels. They are used as adsorbents in filters.

Important from the point of view of industry are silicic acid salts of silicates. They are the basis for the production of substances such as:

• glass;
• concrete;
• cement;
• zeolite;
• kaolin;
• porcelain;
• faience;
• crystal;
• ceramics.

Alkali metal silicates are soluble, all others are not. Therefore, sodium and potassium silicate is called liquid glass. Regular office glue - this is the sodium salt of silicic acid.

But the most interesting compounds are still glass. What only options for this substance come up with! Today receive color, optical, matte options. Glassware amazes with its magnificence and diversity. By adding certain metal oxides and non-metals to the mixture, you can get a variety of glass types. Sometimes even the same composition, but a different percentage of components leads to a difference in the properties of the substance. An example would be porcelain and earthenware, whose formula is SiO 2 * AL 2 O 3 * K 2 O.

Quartz glass is a form of high purity product, whose composition is described as silicon dioxide.

Discoveries in the field of silicon compounds

Over the past few years of research, it has been proven that silicon and its compounds are the most important participants in the normal state of living organisms. With the lack or excess of this element associated diseases such as:

• tuberculosis;
• arthritis;
• cataract;
• leprosy;
• dysentery;
• rheumatism;
• hepatitis and others.

The aging process of the body itself is also associated with the quantitative content of silicon. Numerous experiments on mammals have shown that with a deficiency of an element, heart attacks, strokes, cancer occur and the hepatitis virus is activated.

SILICON,Si (silicium), a chemical element of the IVA subgroup (C, Si, Ge, Sn and Pb) of the Periodic Table of the Elements, non-metal. Silicon in free form was isolated in 1811 by J.Gay-Lussac and L.Tenard when passing fumes of silicon fluoride over metallic potassium, but it was not described by them as an element. The Swedish chemist J. Berzelius in 1823 gave a description of the silicon he obtained by treating the K 2 SiF 6 potassium salt with metallic potassium at a high temperature, but only in 1854 silicon was obtained in the crystalline form A.Deville. Silicon is the second most abundant (after oxygen) element in the Earth's crust, where it is more than 25% (mass). It is found in nature mainly in the form of sand, or silica, which is silicon dioxide, and in the form of silicates (feldspar M (M = Na, K, Ba), kaolinite Al 4 (OH) 8, mica). Silicon can be obtained by calcining crushed sand with aluminum or magnesium; in the latter case, it is separated from the resulting MgO by dissolving magnesium oxide in hydrochloric acid. Technical silicon is produced in large quantities in electric furnaces by reducing silica with coal or coke. Semiconductor silicon is obtained by reducing SiCl 4 or SiHCl 3 with hydrogen, followed by decomposition of the resulting SiH 4 at 400–600 ° C. High-purity silicon is obtained by growing a single crystal from a melt of semiconductor silicon by the Czochralski method or by the method of crucible melting of silicon rods. Elemental silicon is produced mainly for semiconductor technology, in other cases it is used as an alloying additive in the production of steels and non-ferrous metal alloys (for example, to produce FeSi ferrosilicon, which is formed by calcining a mixture of sand, coke and iron oxide in an electric furnace and is used as a deoxidizer and alloying additive in the production of steel and as a reducing agent in the production of ferroalloys).

Application.

Silicon is most widely used in the production of alloys to give strength to aluminum, copper and magnesium and to produce ferrosilicides, which are important in the production of steel and semiconductor technology. Silicon crystals are used in solar cells and semiconductor devices - transistors and diodes. Silicon is also used as a raw material for the production of organosilicon compounds, or siloxanes, obtained in the form of oils, lubricants, plastics and synthetic rubbers. Inorganic silicon compounds are used in the technology of ceramics and glass as an insulating material and piezocrystals.

PROPERTIES OF SILICON
Atomic number	14
Atomic mass	28,086
Isotopes
stable	28, 29, 30
unstable	25, 26, 27, 31, 32, 33
Melting point, ° С	1410
Boiling point, ° C	2355
Density, g / cm 3	2,33
Hardness (Mohs)	7,0
Content in the crust,% (mass.)	27,72
Oxidation states	-4, +2, +4

Properties

Silicon - dark gray, brilliant crystalline substance, brittle and very solid, crystallizes in the diamond lattice. It is a typical semiconductor (it conducts electricity better than a rubber-type insulator, and worse than a conductor - copper). At high temperatures, silicon is highly reactive and interacts with most elements to form silicides, such as magnesium silicate Mg 2 Si, and other compounds, such as SiO 2 (silicon dioxide), SiF 4 (silicon tetrafluoride) and SiC (silicon carbide, carborundum). Silicon is dissolved in a hot alkali solution with evolution of hydrogen: Si + NaOH ® Na 4 SiO 4 + 2H 2 -. 4 (silicon tetrachloride) is obtained from SiO 2 and CCl 4 at high temperature; this colorless liquid boiling at 58 ° C is easily hydrolyzed to form hydrochloric (hydrochloric) acid HCl and orthosilicic acid H 4 SiO 4 (this property is used to create smoke inscriptions: a white cloud of ammonium chloride NH 4 Cl forms) . Silicon tetrafluoride SiF 4 is formed by the action of hydrofluoric (hydrofluoric) acid on glass:

Na 2 SiO 3 + 6HF ® 2NaF + SiF 4 - + 3H 2 O

SiF 4 is hydrolyzed to form orthosilicon and hexafluorosilicon (H 2 SiF 6) acids. H 2 SiF 6 is close in strength to sulfuric acid. Many metal fluorosilicates are soluble in water (sodium, barium, potassium, rubidium, cesium salts are poorly soluble), therefore HF is used to transfer minerals into solution when performing analyzes. The acid itself is H 2 SiF 6 and its salts are poisonous.

\u003e\u003e Chemistry: Silicon and its compounds

The second representative of the elements of the main subgroup of group IV is silicon Si.

In nature silicon - the second most common chemical element after oxygen. More than a quarter of the earth's crust consists of its compounds. The most common silicon compound is its dioxide SiO2, its other name is silica. In nature, it forms the mineral quartz (fig. 46) and many varieties, such as rock crystal and its famous lilac form, amethyst, as well as agate, opal, jasper, chalcedony, and carnelian, which are known as ornamental and semi-precious stones. Silica is also ordinary and quartz sand.

From varieties of minerals on the basis of silicon dioxide - flint, chalcedony and other primitive people manufactured tools. It was flint, this nondescript and not very durable stone, that laid the foundation for the stone age - the age of flint tools. There are two reasons for this: the prevalence and availability of flint, as well as its ability to form sharp cutting edges when chipped.

Fig. 46. ​​Natural quartz crystal (left) and artificially grown (right)

The second type of natural silicon compounds is silicates. Among them, the most common aluminosilicates (it is clear that these silicates contain aluminum). The aluminosilicates include granite, various types of clays, mica. Silicate, not containing aluminum, is, for example, asbestos.

The most important silicon compound  - SiO2 oxide is necessary for plant and animal life. It gives strength to plant stalks and animal protective covers. Thanks to him, reeds, reeds and horsetails stand firmly like bayonets, sharp leaves of sedge cut like knives, stubble on a mowed field stabs like needles, and the stalks of cereals are so strong that they do not allow the cornfield in the fields to fall from rain and wind. Fish scales, insect shells, butterfly wings, bird feathers and animal fur are strong because they contain silica.

Silicon gives smoothness and strength to human bones.

Silicon is also part of the lower living organisms - diatoms and radiolarians - the most delicate lumps of living matter, which create their unsurpassed beauty skeletons from silica.

Silicon properties.   If you use a solar-powered micro-calculator, you probably have an idea of ​​crystalline silicon. This is a semiconductor. In contrast to metals, as the temperature rises, its electrical conductivity increases. On satellites, spaceships and stations install solar panels that convert solar energy into electrical energy. They work crystals of semiconductors, and especially silicon.

Silicon photocells can convert up to 10% of absorbed solar energy into electrical energy.

Silicon burns in oxygen, forming already known silica, or silicon oxide (IV):

Being a non-metal, when heated, it combines with metals to form silicides, for example:

Si + 2Mg = Mg2 Si

Silicides are easily decomposed by water or acids, while the gaseous hydrogen compound silicon - silane is released:

Mg2 Si + 2H2SO4 = 2MgSO4 + SiH4

Unlike hydrocarbons, silane in the air self-ignites and burns to form silicon dioxide and water:

SiH4 + 202 = SiO2 + 2H2O

The increased reactivity of silane in comparison with methane CH4 is explained by the fact that silicon has a larger atom size than carbon, therefore chemical bonds –H are weaker than C – H bonds.

Silicon interacts with concentrated aqueous alkali solutions, forming silicates and hydrogen:

Si + 2NaOH + H20 = Na2SiO3 + 2H2

Silicon is obtained by reducing it from dioxide with magnesium or carbon.

Silica (IV), or silica, or silica, like CO2, is an acidic oxide. However, unlike C02, it has not a molecular, but an atomic crystal lattice. Therefore, SiO2 is a solid and refractory substance. It does not dissolve in water and acids, except, as you know, hydrofluoric, but interacts at high temperatures with alkalis with the formation of silicate salts of silicic acid.

Silicates can also be obtained by fusing silicon dioxide with metal oxides or with carbonates:

SiO2 + CaO = CaSiO3

SiO2 + CaC03 = CaSiO3 + C02

Sodium and potassium silicates are called soluble glass. Their aqueous solutions are a well-known silicate adhesive.

From solutions of silicates, the action of stronger acids — hydrochloric, sulfuric, acetic, and even carbon — produces the acid H2SiO3:

K2SiO3 + 2HCl = 2KSl + H2SiO3

Therefore, H2SiO3 is a very weak acid. It is insoluble in water and drops out of the reaction mixture in the form of a gelatinous precipitate, sometimes compactly filling the entire volume of the solution, turning it into a semi-solid mass, similar to jelly, jelly. When this mass dries, a highly porous substance is formed - silica gel, which is widely used as an adsorbent - absorber of other substances.

The use of silicon. You already know that silicon is used to produce semiconductor materials, as well as acid-resistant alloys. When fused silica sand with coal at high temperatures, silicon carbide SiC is formed, which is only inferior in hardness to diamond. Therefore, it is used for honing the incisors of metal-cutting machines and grinding precious stones.

Various quartz chemical glassware, which can withstand high temperatures and does not crack when quenched, is made from molten quartz.

Silicon compounds serve as the basis for the production of glass and cement.

Ordinary window glass  has a composition that can be expressed by the formula

Na20 CaO 6SiO2

It is produced in special glass furnaces by fusing a mixture of soda, limestone and sand.

A distinctive feature of glass is the ability to soften and, in the molten state, take on any shape that persists when the glass solidifies. This is the basis for the production of tableware and other glass products.

Glass is one of the oldest inventions of mankind. 3-4 thousand years ago glass production was developed in Egypt, Syria, Phenicia and the Black Sea. High perfection in glass making reached the master of ancient Rome. They knew how to get colored glass and make mosaics from pieces of such glass.

Glass is a material not only for craftsmen, but also for artists. Works of art made of glass are indispensable attributes of any large museum. A colorful stained glass churches, mosaic panels - vivid examples. In one of the premises of the St. Petersburg branch of the Russian Academy of Sciences there is a mosaic portrait of Peter I, made by M. V. Lomonosov.

Additional qualities of glass give various additives. Thus, the introduction of lead oxide produces crystal glass, chromium oxide colors the glass green, cobalt oxide blue, and so on.

Scopes of glass are very extensive. This is a window, bottle, lamp, mirror glass; optical glass - from glasses to glasses of cameras; lenses of countless optical devices - from microscopes to telescopes.

Another important material derived from the silicon compound is cement. It is obtained by sintering clay and limestone in special rotary kilns. If the cement powder is mixed with water, a cement paste is formed, or, as builders call it, a “mortar”, which gradually hardens. When sand or crushed stone is added to the cement, concrete is obtained as a filler. The strength of concrete increases if an iron frame is introduced into it, which results in reinforced concrete, from which wall panels, floor blocks, trusses, etc. are prepared.

The silicate industry is engaged in the production of glass and cement. It also produces silicate ceramics - brick, porcelain, earthenware and products made from them.

Silicon discovery . Although already in ancient times people widely used silicon compounds in their everyday life, silicon itself in an elemental state was first obtained in 1825 by the Swedish chemist J. Y. Berzelius. However, Gay-Lussac and L. Tenard received silicon for 12 years before it, but it was very contaminated with impurities.

The Latin name Silicium originates from the Latin. Silex - flint. The Russian name "silicon" comes from the Greek. Kremnos - a cliff, a rock.

1. Natural silicon compounds: silica, quartz and its varieties, silicates, aluminosilicates, asbestos.

2. The biological value of silicon.

3. Silicon properties: semiconductor, interaction with oxygen, metals, alkalis.

5. Silicon oxide (IV). Its structure and properties: interaction with alkalis, basic oxides, carbonates and magnesium.

6. Silicic acid and its salts. Soluble glass.

7. Application of silicon and its compounds.

8. Glass.

9. Cement.

Indicate the similarity and difference between carbon monoxide (IV) and silicon oxide (IV) in structure and properties (interaction with water, alkalis, basic oxides and magnesium). Write the reaction equations.

Why carbon is called the main element of nature, and silicon - the main element of inanimate nature?

By reacting an excess of sodium hydroxide solution with 16 g of silicon, 22.4 l of hydrogen was obtained. What is the mass fraction of silicon in the sample taken? How many grams of silicon oxide contained in it? How many grams of a 60% alkali solution was required for the reaction?

Write the reaction equations, with the help of which the following transformations can be carried out:

a) SiO2 -\u003e Si -\u003e Ca2Si -\u003e SiH4 -\u003e SiO2 -\u003e Si

b) Si -\u003e SiO2 -\u003e Na2SiO3 -\u003e H2SiO3 -\u003e SiO2 -\u003e Si

Consider the oxidation-reduction processes.

The famous mineralogical scientist A.E. Fersman wrote: “A variety of subjects are shown: a transparent ball sparkling in the sun with the purity of cold spring water, a beautiful, colorful agate pattern, a bright game of multicolored opal, pure sand on the seashore, as thin as a silk tree , a string of fused quartz or heat-resistant dishes from it, beautifully cut piles of rock crystal, a mysterious drawing of fantastic jasper, a petrified tree turned into stone, a rough processed arrowhead of an ancient man ... all this is one the same connection ... "What? Complete the quote.

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