Group 4 main subgroup general characteristics. General characteristics of the elements of the main subgroup of group IV. Reactivity of group IV elements

The structure of the electronic shell: ... ns 2 np 2.

CARBON and its compounds

Found in the soil (carbonates), in the air (carbon dioxide), the basis of living and plant life.

Physical properties

Allotropen: a) diamond(sp 3 – hybridization, tetrahedron) – the hardest, does not conduct electric current;

b) graphite(sp 2 – hybridization, hexagonal structure) – easily exfoliates, conducts electric current;

V) carbine(sp – hybridization, linear structure) – semiconductor;

G) coals(X-ray amorphous) – coke, charcoal and bone charcoal, soot.

Chemical properties of carbon and its compounds.

1) Reactions with simple substances:

C + O 2 = CO (CO 2)

C + H 2 = CH 4

C + 2CI 2 = CCI 4

2) Reactions with complex substances(with increased at t o):

a) C + H 2 O = CO + H 2,

b) C + CO 2 = 2CO,

c) C + FeO = Fe + CO,

d) C + H 2 SO 4 (conc.) ® H 2 CO 3 (or CO 2) + SO 2

C + HNO 3 (conc.) ® H 2 CO 3 (or CO 2) + NO (or NO 2)

Oxidation state +2

CO– carbon monoxide, “carbon monoxide” is a colorless, odorless, poisonous gas.

Production of carbon monoxide (P):

a) CO 2 + C = 2CO (incomplete combustion of coal),

b) decomposition of formic acid in the presence of H 2 SO 4 (conc.):

HCOOH ® CO + H 2 O

Chemical properties of carbon monoxide (P):

1)Strong reducing agent:

a) restores metals from oxides: Fe 3 O 4 + 4CO = 3Fe + 4СO 2,

b) CO + CI 2 = COCI 2 – phosgene (poisonous),

c) 2CO + CO 2 = 2CO 2.

2) Participates in organic synthesis, for example CO + 2H 2 ® CH 3 OH.

3) Poisonous, because with incomplete combustion of coal, there can be a “burn”: it combines with hemoglobin in the blood, competing with oxygen, and in the form of carboxyhemoglobin moves along the arterial bed to all cells of the body.

Oxidation state +4

1)CO 2– carbonic anhydride, “carbon dioxide” is a colorless heavy gas that does not support combustion. Solid oxide (t o pl. = -56.5 o C) is often called “dry ice”, because When it melts there is no trace of moisture.

Producing carbon dioxide:

a) in the laboratory: CaCO 3 + 2HCI = CaCI 2 + H 2 CO 3 (CO 2 + H 2 O),

b) in industry by thermal decomposition of limestone:

CaCO 3 ® CaO + CO 2

2)H 2 CO 3– weak, unstable carbonic acid:

K 1 = 4.5 . 10 -7 ; K 2 = 4.7 . 10 -11

3)Salts carbonic acid (carbonates and bicarbonates):

a) acid salts are soluble better than average,

b) salts are well hydrolyzed: CO 3 2- + NOH « NCO 3 - + OH - ,

c) when heated, salts decompose:

MgCO 3 ® MgO + CO 2,

2NaНСО 3 ® Na 2 СО 3 + СО 2 + H 2 О,

4)CS 2– carbon disulfide, volatile toxic colorless liquid, solvent:

CS 2 + 3O 2 = CO 2 + 2SO 2

CS 2 + 2 H 2 O = CO 2 + 2 H 2 S

5)H 2 CS 3– thiocarbonic acid (weak), oily liquid, decomposes with water: H 2 CS 3 + H 2 O = H 2 CO 3 + H 2 S

6) Sulfidecarbonates(thiocarbonates) – similar to carbonates;

a) they can be obtained: K 2 S + CS 2 = K 2 CS 3

b) like carbonates, thiocarbonates are decomposed by acids:

K 2 CS 3 + 2HCI = N 2 CS 3 + 2KSI

1) (CN) 2– cyanogen NºC-CºN – poisonous gas, obtained from the thermal decomposition of cyanides: Hg(CN) 2 ® Hg + (CN) 2

Similar to halogen: a) H 2 + (CN) 2 = 2HCN (hydrocyanic acid) – poison;

b) disproportionates (CN) 2 + 2NaOH = 2NaCN + 2NaCNO.

2)HCN– hydrocyanic acid and its cyanide salts (poisonous, lethal dose 0.05g); weak acid, gives medium and complex salts:

a) 3KCN (poison) + Fe(CN) 3 ® K 3 (not poisonous),

b) 2KCN + O 2 = 2KCNO (cyanate K-O-CºN),

c) NaCN + S = NaCNS (thiocyanate Na-S-CºN).

3)Thiocyanates(rhodanides) – salts of strong thiocyanic (rhodanic) acid HCNS; highly soluble, easily form complexes:

3KCNS + Fe(CNS) 3 ® K 3 .

4)CO(NH 2) - urea (urea).

GENERAL CHARACTERISTICS OF THE SUBGROUP

6 C, 14 Si, 32 Ge, 50 Sn, 82 Pb. They are characterized by allotropy and therefore it is impossible to speak unambiguously about the physical properties of any element. In the subgroup from top to bottom, metallic properties naturally increase and this is consistent with the values ​​of the oxidation states exhibited by the elements in the compounds:

Chemical properties

1. With simple substances they give binary compounds that interact with water in different ways:

C + O 2 = CO 2; CO 2 + H 2 O Û H 2 CO 3 ;

Si + 2F 2 = SiF 4; ;

Ge + 2Cl 2 = GeCl 4; .

(GeO 2 × H 2 O)

2. They interact with acids differently, depending on the predominance of non-metallic or metallic nature:

a) C + 2H 2 SO 4 conc. = CO 2 + 2SO 2 + 2H 2 O;

b) Sn + 4HNO 3 conc. = H 2 SnO 3 + 4NO 2 + H 2 O;

c) Pb + 2HCl = PbCl 2 + H 2.

3. Reactions with alkalis also proceed in different ways:

4. Salts of these elements are hydrolyzed, and the nature of hydrolysis naturally changes according to the subgroup of the corresponding elements:

a) SnCl 4 + 3H 2 O = H 2 SnO 3 ¯ + 4HCl;

(SnO 2 × H 2 O)

b) SnCl 2 + H 2 O Û SnOHCl + HCl;

c) Pb(NO 3) 2 + H 2 O Û PbOHNO 3 + HNO 3.

5. For oxides and hydroxides of these elements, depending on the degree of oxidation, the acidic and basic properties change accordingly:

a) C +4 and Si +4 form weak unstable acids;

b) For compounds of elements of the germanium subgroup with s.o. (+2) the following pattern can be established in the series: they are amphoteric, the basic properties increase with increasing serial number. The same can be said about hydroxides.

c) For compounds of elements of the germanium subgroup with an oxidation state (+4) in the series: amphotericity is maintained, and the acidic properties increase with decreasing atomic number of the element. Salts are formed: meta– (germanates, stannates, plumbates) Me 2 EO 3 and ortho- Me 4 EO 4.

6. Elements form complex compounds, exhibiting concentration values. = 4 (for E +2) and c.h. = 6 (for E +4):

SiF 4 + 2NaF ® Na 2 ;

Sn(OH) 4 + 2NaOH ® Na 2 ;

PbJ 2 + 2KJ ® K 2 .

7. In redox reactions, elements and their compounds exhibit duality:

A) E 0- first of all reducing agent:

C + 2Cl 2 = CCl 4;

Sn + O 2 = SnO 2.

b) E +2 – reducing agents :

CO + Cl 2 = COCl 2 ;

SnCl 2 + 2FeCl 3 = SnCl 4 + 2FeCl 2,

but can also be oxidizing agents:

PbCI 2 + Mg = Pb + MgCI 2

V) E +4 – oxidizing agents(especially active Pb +4 ® Pb +2):

PbO 2 + H 2 O 2 = Pb(OH) 2 + O 2.

General characteristics elements of the main subgroup of group IV General electronic formula. . . ns 2 p 2. Elements have four valence electrons. Their compounds can exhibit oxidation states from +4 to -4. In the subgroup there is a sharp change in the properties of the elements: carbon and silicon are typical non-metals, germanium is a semi-metal, tin and lead are metals. As the atomic radius increases from carbon to lead, the metallic properties increase, and the lowest oxidation state becomes more characteristic. For C, Si, Ge the characteristic oxidation state is +4. For Sn and Pb +2. Only carbon has stable hydrogen compounds; hydrogen compounds are unknown for lead.

Carbon Natural compounds Found in many minerals organic compounds and is found in a free state (diamond, graphite, coal). Four allotropic modifications of carbon are known: diamond, graphite, carbyne, fullerene C 60. Its next stable homologue is C 70, followed by C 76, C 78, C 82, C 84, C 90, C 94, C 96, etc. d C 540. The structure of their molecules is based on one of the corollaries of Euler’s theorem, which says that to line a spherical surface, n hexagons and 12 pentagons are needed, with the exception of n = 1. Graphite - black, soft Diamond - colorless, transparent, very hard. Diamond has a tetrahedral crystal lattice, while the crystal lattice of graphite has a multiplanar structure. Finely dispersed graphite (soot) is called amorphous carbon. Diamond can also be obtained from graphite by heating graphite to 1500 - 2000 C under pressure up to 500 thousand atm.

Chemical properties 1. Carbon is quite inert. When heated to 800 – 900 C, it reacts with non-metals and metals: 2 C + N 2 = C 2 N 2 (cyan or cyanogen) C + Si = Si. C (carborundum); C + O 2 = CO 2 3 C + 4 Al = Al 4 C 3 (aluminum carbide) C + 2 S = CS 2 (carbon disulfide) 2. With oxygen, carbon forms two oxides (CO and CO 2). CO - divalent carbon oxide (carbon monoxide): colorless and odorless, toxic, produced by incomplete combustion of coal. In laboratory conditions it can be obtained by dehydrating formic acid with sulfuric acid.

CO is a good reducing agent and is used to obtain metals from oxides: Cu. O + CO = Cu + CO 2 CO easily enters into addition reactions: CO + Cl 2 = COCl 2 (phosgene) CO + S = COS (carbon thioxide) CO molecules – can act as ligands in carbonyl complexes: Ni + 4 CO = Carbonyl complexes are toxic liquids; widely used to obtain pure metals.

At a temperature of 1000 C, it forms urea (urea) with ammonia: CO 2 + 2 NH 3 = CO(NH 2)2 + H 2 O + CO 2 CO 2 is an acidic oxide of carbonic acid: CO 2 + H 2 O = H 2 CO 3 acid is very weak and unstable. Acid salts (hydrocarbonates) can be obtained by the reaction: Ca. CO 3 + CO 2 + H 2 O = Ca(HCO 3)2 Salts (except alkali metal salts) of carbonic acid are thermally unstable: Zn. CO 3 = Zn. O+CO2

3. When sulfur vapor is passed through hot coal, an oily liquid is formed: carbon disulfide CS 2 CS 2 - is the anhydride of thiocarbonic acid, which is obtained indirectly: CS 2 + Na 2 S = Na 2 CS 3 Na 2 CS 3 + 2 HCl = H 2 CS 3 + 2 Na. Cl This acid is the starting material for the production of monothiocarbonic acid H 2 CO 2 S and dithiocarbonic acid H 2 CO 2 S 2, which are used to produce rayon. 4. With nitrogen, carbon forms cyanogen, a gas with the smell of almonds, highly soluble in water: 2 C + N 2 = (CN)2; (CN)2 + 4 H 2 O = (NH 4)2 C 2 O 4 When cyanogen interacts with alkalis, two series of salts are formed: cyanides and cyanates: (CN)2 + 2 KOH = KCN + KNCO + H 2 O KCN - salt hydrocyanic acid (potassium cyanide), KNCO – salt of cyanic acid (potassium cyanate).

5. When carbon interacts with metals, carbides are formed - composition Me 2 C 2, Me 4 C 3, Me 3 C, which are divided into non-decomposable and decomposable: Ca. C 2 + 2 H 2 O = Ca(OH)2 + C 2 H 2 Al 4 C 3 + 12 HCl = 4 Al. Cl 3 + 3 CH 4 Mn 3 C + 6 H 2 O = 3 Mn(OH)2 + CH 4 + H 2

APPLICATION Mixed halides CCl 2 F 2, CCl 3 F, CBr 3 F are called freons and are used as refrigerants in refrigeration technology. Application of CO 2: as an inert atmosphere when welding metals; V food industry. Na. HCO 3, NH 4 HCO 3 – in baking production. Na 2 CO 3, Ca. CO 3 - in production detergents, glass.

Silicon Silicon occurs naturally in many minerals in the form of Si oxide. O 2, from which elemental silicon can be obtained by reduction with magnesium or carbon. IN pure form silicon is hard, brittle, and has a diamond-like structure. There are amorphous and crystalline silicon.

Chemical properties 1. Silicon is very inert. At high temperatures interacts with fluorine, carbon, and some metals: Si + 2 F 2 = Si. F 4; Si + C = Si. C (carborundum); Si + 2 Mg = Mg 2 Si (silicide). 2. It dissolves well in alkalis and hydrofluoric acid: Si + 4 Na. OH = Na 4 Si. O 4 + 2 H 2 Si + 4 HF = Si. F 4 + 2 H 2 Si. F 4 + 2 HF = H 2 3. Silicon oxide polymer, Si. O 2 forms numerous polysilicic acids. Dissolves in hydrofluoric acid and alkalis: Si. O 2 + 4 HF = Si. F 4 + 2 H 2 O

4. Silicon does not interact directly with hydrogen, therefore hydrogen compounds (silanes) are obtained from silicides: Mg 2 Si + 4 HCl = 2 Mg. Cl 2 + Si. H 4 (monosilane) Silanes can be different composition Si 2 H 6, Si 3 H 8, Si 6 H 14, . . . These are strong reducing agents, very chemically active, and spontaneously ignite in air: Si. H 4 + 2 O 2 = Si. O2 + 2H2O

Application of Si. O 2 is a solid substance with a melting point of 1715 C. It is used in the manufacture of chemical glassware, quartz lamps, etc. Na 2 Si. O 3 – sodium silicate (liquid glass, office glue) Crystalline silicon is the substrate, the basis of semiconductor devices. When silicic acid is calcined, Si is formed. O 2 in the form of an amorphous compound is called “silica gel” and is used as a moisture absorber.

Germanium, tin, lead. Natural compounds Sn. O 2 – casseperite, Pb. S – lead gloss. Germanium does not have its own ores; it is found with ores of zinc, tin, and lead. Tin and lead are obtained by the pyrometallurgical method: tin - by reduction with carbon from oxide, lead - by roasting sulfide in oxygen, and reduction with carbon (II) oxide to metal. Germanium gets more in a complicated way: First, germanium tetrachloride Ge is obtained. Cl4Ge. Cl 4 + H 2 O = Ge. O 2 + 4 HCl Ge. O 2 + 2 H 2 = Ge + 2 H 2 O

Germanium and tin are white, shiny metals that oxidize weakly in air. Lead - gray due to the oxide film. Tin is polymorphic. At temperatures > +13 C, the β modification is stable. As the temperature decreases, βtin transforms into the α modification. This transition begins at +13 C and proceeds very quickly at -33 C, as a result of which tin turns into powder. This phenomenon is called “tin plague”.

Chemical properties 1. When heated, they react with non-metals. 2 Pb + O 2 = 2 Pb. O; Ge + 2 S = Ge. S2; Sn + 2 Cl 2 = Sn. Cl 4 3. Germanium and tin do not interact with water. Lead dissolves slowly in water: 2 Pb + O 2 + 2 H 2 O = 2 Pb(OH)2 4. In the activity series, Ge is between Cu and Ag, i.e. after hydrogen, and Sn and Pb before hydrogen. Tin weakly displaces hydrogen: Sn + H 2 SO 4 (div) = Sn. SO 4 + H 2 Similar reactions with lead practically do not occur, because Pb. Cl 2 and Pb. SO 4 is poorly soluble.

Lead and tin interact similarly (in concentrated lead is passivated): 3 Pb + 8 HNO 3 (diluted) = 3 Pb(NO 3)2 + 2 NO + 4 H 2 O Tin and germanium react with concentrated nitric acid: Sn + 4 HNO 3 = H 2 Sn. O 3 + 4 NO 2 + H 2 O 5. All three elements react with alkalis (germanium in the presence of an oxidizing agent): Sn + 2 Na. OH + 2 H 2 O = Na 2 + H 2 Ge + 2 Na. OH + 2 H 2 O 2 = Na 2

Use of Ge - as a semiconductor material, Sn and Pb mainly in the form of alloys (bronze, babbitt), Sn - as protective coating against corrosion, Pb 3 O 4 - as a dye, Pb(C 2 H 5)4 (tetraethyl lead) - an additive in gasoline (anti-knock).

Elements of the secondary subgroup of group IV -. Found in nature in the form of minerals: Fe. Ti. O 3 – ilmenite, Ti. O 2 – rutile, Zr. Si. O 4 – zircon. Hf does not have its own ores; it is found in ores of zirconium, iron, and manganese. Ti is obtained by pyrometallurgical process from Ti. Cl 4 or Ti. O2:Ti. O 2 + 2 Mg = Ti + 2 Mg. O Purification of titanium from impurities is usually carried out using the gas transport method: Ti + 2 J 2 → Ti. J 4 → Ti + 2 J 2 Zirconium and hafnium are obtained by electrolysis of molten salts.

Pure metals are tough, impact-resistant, with high melting points (Ti – 1700 C, Zr – 1900 C, Hf – 2200 C). Ti is a light metal, its density is 4.5 g/cm3. Chemically, titanium is the most active. Zirconium and hafnium are less active.

Chemical properties 1. Characteristic oxidation states in compounds for Ti +4, +3; for Zr and Hf +4. When heated, all three elements actively interact with various non-metals: Zr + C = Zr. C; Hf + 2 S = Hf. S2; 2 Ti + N 2 = 2 Ti. N; Ti + 2 Cl 2 = Ti. Cl 4 2. They react poorly with acids Ti, Zr and Hf. Only titanium dissolves in nitric acid: Ti + 4 HNO 3 = H 2 Ti. O 3 + 4 NO 2 + H 2 O

Zirconium and hafnium interact only with “ royal vodka”: 3 Hf + 18 HCl + 4 HNO 3 = 3 H 2 + 4 NO + 8 H 2 O 3. Ti oxides. O 2 – amphoteric, Zr. O 2 – weakly amphoteric, Hf. O 2 – basic. 4. When interacting with sulfuric acid, the oxides form the corresponding sulfates, which quickly hydrolyze to titanyl, zirconyl, hafnyl sulfate: Ti. O 2 + 2 H 2 SO 4 = Ti(SO 4)2 + 2 H 2 O Ti(SO 4)2 + H 2 O = Ti. OSO 4 + H 2 SO 4 In amphoteric Ti. O 2 has a more pronounced acidic function. Its corresponding metatitanic acid is H 2 Ti. O 3 exists in two modifications α and β. General formula of titanic acids x. Ti. O2·y. H2O.

Application Titanium is the third most important (after iron and aluminum) structural material. Titanium is used in the form of alloys in ships, rocketry, and mechanical engineering. Zirconium and hafnium are used in nuclear reactor construction (zirconium for shells of fuel elements, hafnium for control rods to absorb neutrons during reactor operation).

Lesson Plan

General characteristics of elements of group IV A.

Carbon and silicon

Target:

Educational: to form in students general idea about the elements included in the 4th group, study their basic properties, consider their biochemical role and the use of the main compounds of elements.

Developmental: develop skills in written and oral speech, thinking, and the ability to use acquired knowledge to solve various tasks.

Educating: cultivate a sense of the need to learn new things.

Lesson progress

Repetition of the covered topic:

How many elements are nonmetals? Indicate their place in PSHE?

What elements are classified as organogenic?

Specify physical state all non-metals.

How many atoms do nonmetal molecules consist of?

What oxides are called non-salt-forming? Write the formulas of non-salt-forming non-metal oxides.

Cl 2 → HCl → CuCl 2 → ZnCl 2 → AgCl

Write the last reaction equation in ionic form.

Add possible reaction equations:

1) H 2 + Cl 2 = 6) CuO + H 2 =

2) Fe + Cl 2 = 7) KBr + I 2 =

3) NaCl + Br 2 = 8) Al + I 2 =

4) Br 2 + KI = 9) F 2 + H 2 O =

5) Ca + H 2 = 10) SiO 2 + HF =

Write down the reaction equations for the interaction of nitrogen with a) calcium; b) with hydrogen; c) with oxygen.

Carry out a chain of transformations:

N 2 → Li 3 N → NH 3 → NO → NO 2 → HNO 3

When 192 g of ammonium nitrite was decomposed by the reaction NH 4 NO 2 = N 2 + 2H 2 O, 60 liters of nitrogen were obtained. Find the yield of the product from the theoretically possible.

Learning new material.

Group 4A includes p-elements: carbon, silicon, germanium, tin and lead. Differing in the number of energy levels, their unexcited atoms have 4 electrons at the outer level. Due to the increase in the number of filled electronic layers and the size of the atom in the group from top to bottom, the attraction of outer valence electrons to the nucleus is weakened, therefore the non-metallic properties of the elements in the subgroup from top to bottom are weakened and the metallic properties are enhanced. However, carbon and silicon have significantly different properties from other elements. These are typical non-metals. Germanium has metallic characteristics, and in tin and lead they predominate over non-metallic ones.

In nature carbon It is found in a free state in the form of diamond and graphite. The carbon content in the earth's crust is about 0.1%. It is part of natural carbonates: limestone, marble, chalk, magnesite, dolomite. Carbon is the main component organic matter. Coal, peat, oil, wood and natural gas are usually considered as combustible materials used as fuel.

Physical properties. Carbon as a simple substance exists in several allotropic forms: diamond, graphite, carbyne and fullerene, which have sharply different physical properties, which is explained by the structure of their crystal lattices. Carbin – a finely crystalline black powder, first synthesized in the 60s by Soviet chemists, and later found in nature. When heated to 2800º without air access, it turns into graphite. Fullerene - in the 80s, spherical structures formed by carbon atoms were synthesized, called fullerenes. They are closed structures consisting of a certain number of carbon atoms - C 60, C 70.

Chemical properties. Chemically, carbon is normal conditions inert. Reactivity increases with increasing temperature. At high temperatures, carbon reacts with hydrogen, oxygen, nitrogen, halogens, water and some metals and acids.

When water vapor is passed through hot coal or coke, a mixture of carbon monoxide (II) and hydrogen is obtained:

C + H 2 O = CO + H 2 ( water vapor ),

This reaction takes place at 1200º, at temperatures below 1000º oxidation occurs to CO 2 :

C + 2H 2 O= CO 2 + 2 H 2 .

An industrially important process is the conversion of water gas to methanol (methyl alcohol):

CO + 2H 2 = CH 3 HE

When exposed to high temperatures, carbon is able to interact with metals, forming carbide, Among them, “methanides” and “acetylenides” are distinguished, depending on what gas is released when they interact with water or acid:

SaS 2 + HCl = CaCl 2 + C 2 H 2

Al 4 C 3 + 12 H 2 O = 2 Al(OH) 3 ↓ + 3 CH 4

Calcium carbide, which is obtained by heating lime CaO and coke in electric furnaces without air access, is of great practical importance:

CaO + 3C = CaC 2 + CO

Calcium carbide is used to produce acetylene:

SaS 2 + 2 H 2 O= Ca(OH) 2 + C 2 H 2

However, carbon is characterized by reactions in which it exhibits reducing properties:

2 ZnO + C = Zn+ CO 2

Ccarbon unification.

Carbon monoxide (CO) is carbon monoxide. Industrially, it is produced by passing carbon dioxide over hot coal at high temperature. In laboratory conditions, CO is obtained by the action of concentrated sulfuric acid on formic acid when heated (sulfuric acid takes away water):

UNSOUN =H 2 O+ CO

Carbon monoxide (CO 2) is carbon dioxide. In the atmosphere, carbon dioxide is 0.03% by volume, or 0.04% by mass. Volcanoes and hot springs supply the atmosphere, and finally, humans burn fossil fuels. The atmosphere constantly exchanges gases with ocean water, which contains 60 times more carbon dioxide than the atmosphere. It is known that carbon dioxide absorbs well sun rays V infrared region spectrum Thus, carbon dioxide creates greenhouse effect and regulates global temperature.

In laboratory conditions, carbon dioxide is produced by the action of hydrochloric acid on marble:

SaCO 3 + 2 HCl = CaCl 2 + H 2 O+ CO 2

The property of carbon dioxide not to support combustion is used in fire-fighting devices. As pressure increases, the solubility of carbon dioxide increases sharply. This is the basis for its use in the production of fizzy drinks.

Carbonic acid exists only in solution. When the solution is heated, it decomposes into carbon monoxide and water. The salts of the acid are stable, although the acid itself is unstable.

The most important reaction to the carbonate ion is the action of dilute mineral acids - hydrochloric or sulfuric. At the same time, bubbles of carbon dioxide are released with hissing, and when it is passed through a solution of calcium hydroxide (limewater), it becomes cloudy as a result of the formation of calcium carbonate.

Silicon. After oxygen, it is the most abundant element on Earth. It makes up 25.7% of the mass earth's crust. A significant part of it is represented by silicon oxide, called silica, which occurs in the form of sand or quartz. In very pure form, silicon oxide occurs as a mineral called rock crystal. Crystalline silicon oxide, colored with various impurities, forms precious and semi-precious stones: agate, amethyst, jasper. Another group of natural silicon compounds is silicates - derivatives silicic acid.

In industry, silicon is obtained by reducing silicon oxide with coke in electric furnaces:

SiO 2 + 2 C = Si + 2 CO

In laboratories, magnesium or aluminum is used as reducing agents:

SiO 2 + 2Mg = Si + 2MgO

3 SiO 2 + 4Al = Si + 2Al 2 O 3 .

The purest silicon is obtained by reducing silicon tetrachloride with zinc vapor:

SiCl 4 + 2 Zn = Si + 2 ZnCl 2

Physical properties. Crystalline silicon is a brittle substance of dark gray color with a steely sheen. The structure of silicon is similar to that of diamond. Silicon is used as a semiconductor. The so-called solar panels, converting light energy into electrical energy. Silicon is used in metallurgy to produce silicon steels, which have high heat resistance and acid resistance.

Chemical properties. In terms of chemical properties, silicon, like carbon, is a non-metal, but its non-metallicity is less pronounced, since it has a large atomic radius.

Silicon at normal conditions chemically quite inert. It reacts directly only with fluorine, forming silicon fluoride:

Si + 2 F 2 = SiF 4

Acids (except for a mixture of hydrofluoric acid and nitric acid) have no effect on silicon. But it dissolves in alkali metal hydroxides:

Si + NaOH + H 2 O=Na 2 SiO 3 + 2H 2

At high temperatures in electric oven silicon carbide is obtained from a mixture of sand and coke SiC– carborundum:

SiO 2 + 2C =SiC+ CO 2

Whetstones and grinding wheels are made from silicon carbide.

Compounds of metals with silicon are called silicides:

Si + 2 Mg = Mg 2 Si

When magnesium silicide is treated with hydrochloric acid, the simplest hydrogen compound of silicon is obtained silane –SiH 4 :

Mg 2 Si+ 4NSl = 2 MdCl 2 + SiH 4

Silane is a poisonous gas with unpleasant smell, self-flammable in air.

Silicon compounds. Silicon dioxide– a solid, refractory substance. In nature, it is distributed in two types crystalline and amorphous silica. Silicic acid- is a weak acid; when heated, it easily decomposes into water and silicon dioxide. It can be obtained either in the form of a gelatinous mass containing water or in the form of a colloidal solution (sol). Silicic acid salts are called silicates. Natural silicates are quite complex compounds; their composition is usually depicted as a combination of several oxides. Only sodium and potassium silicates are soluble in water. They are called soluble glass, and their solution – liquid glass.

Tasks for consolidation.

2. Add possible reaction equations and solve the problem.

Crossword.

Pabout vertical: 1. Carbonic acid salt.

Horizontal: 1. The hardest natural substance on Earth. 2. Construction material. 3. Substance used to make dough. 4. Silicon compounds with metals. 5. Element of the main subgroup 1V of the PS group chemical elements. 6. Salts of carbonic acid containing hydrogen. 7. Natural silicon compound.

Homework: pp.210 – 229.

General characteristics of elements of group IV, the main subgroup periodic table D. I. Mendeleev

The elements of the main subgroup of group IV include carbon, silicon, germanium, tin, and lead. Metallic properties are enhanced, non-metallic properties are reduced. The outer layer has 4 electrons.

Chemical properties(carbon based)

· Interact with metals

4Al+3C = Al 4 C 3 (reaction occurs at high temperature)

· Interact with non-metals

2H 2 +C = CH 4

· Interact with oxygen

· Interact with water

C+H2O = CO+H2

· Interact with oxides

2Fe 2 O 3 +3C = 3CO 2 +4Fe

· Interact with acids

3C+4HNO3 = 3CO2 +4NO+2H2O

Carbon. Characteristics of carbon, based on its position in the periodic table, allotropy of carbon, adsorption, distribution in nature, production, properties. The most important carbon compounds

Carbon (chemical symbol - C, lat. Carboneum) is a chemical element of the fourteenth group (according to the outdated classification - the main subgroup of the fourth group), the 2nd period of the periodic system of chemical elements. serial number 6, atomic mass- 12.0107. Carbon exists in many allotropic modifications with very diverse physical properties. The variety of modifications is due to the ability of carbon to form chemical bonds different types.

Natural carbon consists of two stable isotopes - 12C (98.93%) and 13C (1.07%) and one radioactive isotope 14C (β-emitter, T½ = 5730 years), concentrated in the atmosphere and upper part of the earth's crust.

The main and well-studied allotropic modifications of carbon are diamond and graphite. Under normal conditions, only graphite is thermodynamically stable, while diamond and other forms are metastable. Liquid carbon exists only at a certain external pressure.

At pressures above 60 GPa, the formation of a very dense modification C III (density 15-20% higher than the density of diamond), which has metallic conductivity, is assumed.

The crystalline modification of carbon of the hexagonal system with a chain structure of molecules is usually called carbyne. Several forms of carbyne are known, differing in the number of atoms in the unit cell.

Carbyne is a fine-crystalline black powder (density 1.9-2 g/cm³) and has semiconductor properties. Received in artificial conditions made up of long chains of carbon atoms arranged parallel to each other.

Carbyne is a linear polymer of carbon. In the carbyne molecule, carbon atoms are connected in chains alternately either by triple and single bonds (polyene structure) or permanently by double bonds (polycumulene structure). Carbyne has semiconducting properties, and its conductivity increases greatly when exposed to light. The first practical application is based on this property - in photocells.

Graphene is a two-dimensional allotropic modification of carbon, formed by a layer of carbon atoms one atom thick, connected through sp² bonds into a hexagonal two-dimensional crystal lattice.

At ordinary temperatures, carbon is chemically inert; at sufficiently high temperatures it combines with many elements and exhibits strong reducing properties. Chemical activity different forms carbon decreases in the series: amorphous carbon, graphite, diamond; in air they ignite at temperatures respectively above 300-500 °C, 600-700 °C and 850-1000 °C.

The combustion products of carbon are CO and CO2 (carbon monoxide and carbon dioxide, respectively). Unstable suboxide carbon C3O2 (melting point −111 °C, boiling point 7 °C) and some other oxides (for example, C12O9, C5O2, C12O12) are also known. Graphite and amorphous carbon begin to react with hydrogen at a temperature of 1200 °C, with fluorine at 900 °C.

Carbon dioxide reacts with water to form weak carbonic acid - H2CO3, which forms salts - carbonates. The most widespread on Earth are calcium carbonates (mineral forms - chalk, marble, calcite, limestone, etc.) and magnesium (mineral form dolomite).

Graphite with halogens, alkali metals, etc.
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substances form inclusion compounds. When skipping electrical discharge Cyanogen is formed between the carbon electrodes in a nitrogen atmosphere. At high temperatures, the reaction of carbon with a mixture of H2 and N2 produces hydrocyanic acid:

The reaction of carbon with sulfur produces carbon disulfide CS2; CS and C3S2 are also known. With most metals, carbon forms carbides, for example:

The reaction of carbon with water vapor is important in industry:

When heated, carbon reduces metal oxides to metals. This property Widely used in the metallurgical industry.

Graphite is used in the pencil industry, but mixed with clay to reduce its softness. Diamond, due to its exceptional hardness, is an indispensable abrasive material. In pharmacology and medicine, various carbon compounds are widely used - derivatives of carbonic acid and carboxylic acids, various heterocycles, polymers and other compounds. Carbon plays a huge role in human life. Its applications are as diverse as this multifaceted element itself. In particular, carbon is an integral component of steel (up to 2.14% wt.) and cast iron (more than 2.14% wt.)

Carbon is part of atmospheric aerosols, due to which the regional climate can change and the number of sunny days can decrease. Carbon enters environment in the form of soot in the exhaust gases of vehicles when burning coal at thermal power plants, during open coal mines, underground gasification, production of coal concentrates, etc.
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Carbon concentration above combustion sources is 100-400 μg/m³, major cities 2.4-15.9 µg/m³, rural areas 0.5 - 0.8 µg/m³. With gas aerosol emissions from nuclear power plants, (6-15)·109 Bq/day 14СО2 enters the atmosphere.

High content carbon in atmospheric aerosols leads to increased morbidity among the population, especially in the upper respiratory tract and lungs. Occupational diseases - mainly anthracosis and dust bronchitis. In the air working area MPC, mg/m³: diamond 8.0, anthracite and coke 6.0, coal 10.0, carbon black and carbon dust 4.0; V atmospheric air maximum one-time 0.15, average daily 0.05 mg/m³.

The most important connections. Carbon (II) monoxide (carbon monoxide) CO. Under normal conditions, it is a colorless, odorless, and tasteless gas. The toxicity is explained by the fact that it easily combines with blood hemoglobin Carbon monoxide (IV) CO2. Under normal conditions, it is a colorless gas with a slightly sour smell and taste, one and a half times heavier than air, does not burn and does not support combustion. Carbonic acid H2CO3. Weak acid. Carbonic acid molecules exist only in solution. Phosgene COCl2. Colorless gas with a characteristic odor, boiling point = 8°C, melting point = -118°C. Very poisonous. Slightly soluble in water. Reactive. Used in organic syntheses.

General characteristics of elements of group IV, the main subgroup of D.I. Mendeleev’s periodic system - concept and types. Classification and features of the category "General characteristics of elements of group IV, the main subgroup of the periodic table of D. I. Mendeleev" 2017, 2018.

Metallic properties are enhanced, non-metallic properties are reduced. There are 4 electrons on the outer layer.

Chemical properties(carbon based)

Interact with metals:

4Al + 3C = Al 4 C 3 (idset reaction at high temperature)

Interact with non-metals:

2H 2 + C = CH 4

Interact with water:

C + H 2 O = CO + H 2

2Fe 2 O 3 + 3C = 3CO 2 + 4Fe

Interact with acids:

3C + 4HNO3 = 3CO2 + 4NO + 2H2O

Carbon. Characteristics of carbon based on its position in the periodic table, allotropy of carbon, adsorption, distribution in nature, production, properties. The most important carbon compounds

Carbon (chemical symbol - C, lat. Carboneum) is a chemical element of the fourteenth group (according to the outdated classification - the main subgroup of the fourth group), the 2nd period of the periodic table of chemical elements. serial number 6, atomic mass - 12.0107.

Carbon exists in a variety of allotropes with very diverse physical properties. The variety of modifications is due to the ability of carbon to form chemical bonds of different types.

Natural carbon consists of two stable isotopes - 12C (98.93%) and 13C (1.07%) and one radioactive isotope 14C (β-emitter, T½ = 5730 years), concentrated in the atmosphere and upper part of the earth's crust.

The main and well-studied allotropic modifications of carbon are diamond and graphite. Under normal conditions, only graphite is thermodynamically stable, while diamond and other forms are metastable. Liquid carbon exists only at a certain external pressure.

At pressures above 60 GPa, the formation of a very dense modification C III (density 15-20% higher than the density of diamond), which has metallic conductivity, is assumed.

The crystalline modification of carbon of the hexagonal system with a chain structure of molecules is called carbyne. Several forms of carbyne are known, differing in the number of atoms in the unit cell.

Carbyne is a fine-crystalline black powder (density 1.9-2 g/cm³) and has semiconductor properties. Obtained under artificial conditions from long chains of carbon atoms laid parallel to each other.

Carbyne is a linear polymer of carbon. In the carbyne molecule, the carbon atoms are connected in chains alternately either by triple and single bonds (polyene structure) or permanently by double bonds (polycumulene structure). Carbyne has semiconducting properties, and its conductivity increases greatly when exposed to light. The first practical application is based on this property - in photocells.

The reaction of carbon with sulfur produces carbon disulfide CS2; CS and C3S2 are also known.

With most metals, carbon forms carbides, for example:

The reaction of carbon with water vapor is important in industry:

When heated, carbon reduces metal oxides to metals. This property is widely used in the metallurgical industry.

Graphite is used in the pencil industry, but mixed with clay to reduce its softness. Diamond, due to its exceptional hardness, is an indispensable abrasive material. In pharmacology and medicine, various carbon compounds are widely used - derivatives of carbonic acid and carboxylic acids, various heterocycles, polymers and other compounds. Carbon plays a huge role in human life. Its applications are as varied as this many-sided element itself. In particular, carbon is an integral component of steel (up to 2.14% wt.) and cast iron (more than 2.14% wt.)

Carbon is part of atmospheric aerosols, as a result of which the regional climate may change and the number of sunny days may decrease. Carbon enters the environment in the form of soot in the exhaust gases of vehicles, during the combustion of coal at thermal power plants, during open-pit coal mining, underground gasification, production of coal concentrates, etc. The carbon concentration above combustion sources is 100-400 μg/m³, in large cities 2 .4-15.9 µg/m³, rural areas 0.5-0.8 µg/m³. With gas aerosol emissions from nuclear power plants, (6-15) · 109 Bq/day 14СО2 enters the atmosphere.

The high carbon content in atmospheric aerosols leads to increased morbidity in the population, especially in the upper respiratory tract and lungs. Occupational diseases are mainly anthracosis and dust bronchitis. In the air of the working area, MPC, mg/m³: diamond 8.0, anthracite and coke 6.0, coal 10.0, carbon black and carbon dust 4.0; in atmospheric air the maximum one-time is 0.15, the average daily is 0.05 mg/m³.

The most important connections. Carbon (II) monoxide (carbon monoxide) CO. Under normal conditions, it is a colorless, odorless, and tasteless gas. The toxicity is explained by the fact that it easily combines with hemoglobin in the blood.

Carbon monoxide (IV) CO2. Under normal conditions, it is a colorless gas with a slightly sour smell and taste, one and a half times heavier than air, does not burn and does not support combustion.
Carbonic acid H2CO3. Weak acid. Carbonic acid molecules exist only in solution.

Phosgene COCl2. Colorless gas with a characteristic odor, boiling point = 8°C, melting point = -118°C. Very poisonous. Slightly soluble in water. Reactive. Used in organic syntheses.