Metal communication is a bond formed between atoms under conditions of severe delocalization (the propagation of valence electrons in several chemical bonds in compound) and the deficiency of electrons in the atom (crystal). It is unsaturated and spatially non-directional.

Delocalization of valence electrons in metals is a consequence of a multicenter character metal bond. Multical centers of metal communication provides high electrical conductivity and thermal conductivity of metals.

Saturability Determined by the number of valence orbitals involved in the formation of Chem. Communication. Quantitative characteristic - valence. Valence - the number of connections that can form one atom with others; - determined by the number of valence orbitals participating in the formation of communication on the exchange and donor-acceptor mechanism.

Food - the connection is formed in the direction of maximum overlapping of electronic clouds; - determines the chemical and crystalochemical structure of the substance (as the atoms in the crystal lattice are associated).

In the formation of a covalent bond, electron density is concentrated between interacting atoms. (drawing from the notebook). In the case of a metallic coupling, electronic density is delocalized throughout the crystal. (drawing from the notebook)

(Example from the notebook)

Due to the unsaturation and non-directional of metallic communications, metal bodies (crystals) are highly symmetric and highly coordinated. The overwhelming majority of crystalline metal structures correspond 3 types of atom packings in crystals:

1. HCC- Grenetzentarized cubic dense resistant structure. Packing density - 74.05%, coordination number \u003d 12.

2. GPU- hexogonal tight-packed structure, packaging density \u003d 74.05%, K.C. \u003d 12.

3. OCC- the volume is centered, the density of the package \u003d 68.1%, K.ch. \u003d 8.

Metal communication does not exclude a certain seal of covalency. The metal bond is in pure form is characteristic only for alkaline and alkaline-land metals.

Pure metal communication is characterized by the energy of about 100/150/200 kJ / mol, 4 times weaker than covalent.

36. Chlorine and its properties. B \u003d 1 (III, IV, V and VII) Step. Sounds \u003d 7, 6, 5, 4, 3, 1, -1

yellow-green gas with a sharp annoying smell. Xlore is found in nature only in the form of connections. In nature in the form of chloride potassium, magnesium, nitrium, formed in the sharp evaporation of the former seas, lakes. Obtaining: 2NaCl + 2H2O \u003d 2NAOH + H2 + CL2, electrolysis of water ps chloridesMe. \\ 2kmnO4 + 16HCl \u003d 2mnCl2 + 2KCl + 8H2O + 5Cl2 / Chemically chlorine is very active, directly connects with almost all IU, and non-metals (except Carbon, nitrogen, oxygen, inert gases), replaces hydrogen in the prevolution and joins unsaturated compounds, displaces bromine and iodine from their compounds. Phosphor flammifies in the atmosphere of chlorine RSL3, and with further chlorination - RSL5; Sulfur with chlorine \u003d S2CL2, SSL2 and other SNCLM. A mixture of chlorine with hydrogen is burning. With oxygen chlorine forms oxides: CL2O, CLO2, CL2O6, CL2O7, CL2O8, as well as hypochlorites (chlorothic acid salts), chlorite, chlorates and perchlorates. Everything oxygen compounds Chlorine form explosive mixtures with easily oxidizing substances. The chlorine oxides of a small resistant and can spontaneously explode, hypochlorites during storage are slowly decomposed, chlorates and perchlorates can explode under the influence of the initiators. In the water -Hlornoty and SOL: SL2 + H2O \u003d nsLo + HCl. In the chlorination of aqueous solutions, hypochlorites and chlorides are formed on cold alkali: 2None + CL2 \u003d NASLO + NASL + H2O, and when heated is chlorates. In the interaction of ammonia with chlorine, three chloride nitrogen is formed. With other halogens intergenogenic compounds. Fluorides CLF, CLF3, CLF5 are very reactive; For example, in the CLF3 atmosphere, glass wool is self-proposal. Known chlorine compounds with oxygen to fluorine - chlorine oxyfluoride: CLO3F, CLO2F3, CLOF, CLOF3 and Fluoro FCLO4 perchlorate. Application:production of chemicalsOed, water purification, syntheses in food, farm Prom-Tu-bactericid, antisept., Whitening of papers, tissues, pyrotechnics, matches, in CXTs destroy weeds.

Biological role: biogenic, component of plant tissues and animals. 100g The main osmotically active substance of blood plasma, lymphs, cerebrospinal fluid and some tissues. Sodium chloride is required \u003d 6-9g-bread, meat and dairy products. Plays a role in water-salt exchanging, contributing to keeping water tissues. Regulation of acid-alkaline equilibrium in tissues is carried out along with other processes by change in chlorine distribution between blood and other tissues, chlorine is involved in the energy exchange in plants, activating both oxidative phosphorylation and photo phosphorylation. XLOR has a positive effect on the absorption of oxygen roots, the blast component.

37. Hydrogen, water. V \u003d 1; st. Okisl \u003d + 1-1 Hydrogen ion is completely deprived of electronic shells, can fit at very close distances, introduced into electronic shells.

The most common element of the universe. It is the main mass of the sun, stars and other cosmic tel. In the free state on Earth, it is found relatively rarely - it is contained in oil and combustible gases, is present in the form of inclusions in some minerals, large. Part of water. Receipt: 1. LaboratoryZn + 2HCl \u003d ZnCl2 + H 2; 2.Si + 2NAOH + H 2 O \u003d Na 2 SiO 3 + 2H 2; 3. Al + NaOH + H 2 O \u003d Na (Aloh) 4 + H 2. 4. In industry: conversion, electrolysis: CH4 + H2O \u003d CO + 3H2 \\ CO + H2O \u003d CO + H.2 / Chem Sv-Va.In N.U.: H 2 + F 2 \u003d 2HF. When irradiation, lighting, catalysts: H 2 + O 2, S, N, P \u003d H 2 O, H 2 S, NH 3, Ca + H2 \u003d San2 \\ F2 + H2 \u003d 2HF \\ N2 + 3H2 → 2NH3 \\ CL2 + H2 → 2HCl, 2NO + 2H2 \u003d N2 + 2H2O, Cuo + H2 \u003d Cu + H2O, CO + H2 \u003d CH3OH. Hydrogen forms hydrides: ionic, covalent and metal. To ion -nah - & Cah 2 - & + H 2 O \u003d Ca (OH) 2; NAH + H 2 O \u003d NaOH + H 2. Covalent -B 2 H 6, Alh 3, Sih 4. Metal -SD-elements; Composition variable: MEH ≤1, MEH ≤2 - introduced in emptiness between atoms. Heat, current, solid. Water.p3-hybrid Sylopolarn.Molecules at an angle of 104.5 , dipoles, NAB.Raspolt.Ratcher. Support is reagent at room T: with active men with halogens (F, CL) and intermediate compounds of the salts, images weak to-so and weak, causing their full hydrolysis ; With anhydrides and halogen chidrides of carbon and inorganic. Kis-T; with active metal compounds; with carbides, nitrides, phosphide, silicide, hydrides of active ME; With many salts, forming hydrates; with borants, silanes; with keten, carbon monoxide; with noble gases. Water reagrates when heated: with FE, MGC coal, methane; with some alkyl halides. Application: hydrogen -Sintez ammonia, methanol, chloride, tv.zhirov, hydrogen flame - for welding, melting, in metallurgy for the reduction of oxide, fuel for missiles, in pharmacy-water, peroxide-antisept, bactericide, washing, hair discoloration, sterilization.

Biol.rol: hydrogen-7kg, the main function of hydrogen is structuring the biological space (water and hydrogen bonds) and the formation of a diversity of org molecules (enters the structure of proteins, carbohydrates, fats, enzymes) due to hydrogen bonds

copy DNA molecule. Water takes part in huge

the number of biochemical reactions, in all physiological and biological

processes, ensures the metabolism between the organism and the external environment, between

cells and inside cells. Water is a structural base of cells necessary for

maintain the optimal volume, it determines the spatial structure and

biomolecules features.

The name "Metal Communication" indicates that it will be about the internal structure of metals.

Atoms of most metals at the external energy level contain a small number of valence electrons compared with the total number of external energy-close orbitals, and valence electrons due to a small ionization energy are weakly held in atom. Therefore, it is energetically more profitable that the electrons are not localized, but belonged to the entire metal. So, one electron contains 16 elements, two - 58, three - 4 elements and not only one PD. Only atoms of elements GE, Sn and Pb are at the outer level of 4 electrons, SB and BI - 5 and PO - 6. But these elements are not characteristic metals.

Elements - metal form simple substances. Under normal conditions, these are crystalline substances (except mercury). According to the theory of "free electrons" in the metal grilles, there are positively charged ions, which are immersed in electronic "gas" distributed throughout the metal, from non-silized valence electrons. There is electrostatic interaction between positively charged metal ions and non-silized electrons, which ensures the resistance of the substance.

In fig. 3.17 shows the scheme crystal lattice Sodium metal. In it, each sodium atom is surrounded by eight neighboring atoms. On the example of this substance, consider a metal connection.

At the sodium atom, like all metals, there is an excess of valented orbitals and a lack of electrons. Thus, its valence electron (3s 1) can occupy one of 9 free orbital: 3S (one), SP (three) and 3D (five). Under the rapprochement of atoms, as a result of the formation of a crystal lattice, the valence orbitals of neighboring atoms overlap, due to which the electrons are freely moving from one orbital to another, communicating between all the atoms of the metal crystal (Fig. 3.18).

In this way, metal communication is strongly non-silized chemical communicationsarising in the case when atoms have little valence electrons compared to the number of free valence orbitals, and valence electrons due to low ionization energy are weakly held by the kernel.

Metal communication has some similarity with covalent, since it is based on the generalization of valence electrons. However, with a covalent connection, valence electrons are generalized only two neighboring atoms, while all atoms are involved in the generalization of these electrons. That is why crystals with a covalent bond of fragile, and from metal - plastic; In the latter case, the mutual displacement of ions and electrons without disrupting communication is possible. This suggests non-sharply (lack of orientation) of a metallic connection. The presence of electrons that can freely move in terms of crystal, provides high electrical conductivity and thermal conductivity, as well as hardware. The metal glitter is due to the reflection of light rays from the electron gas, which is somewhat abroad of positively charged ions. It is the metallic bond that explains the physical properties of metals.

Metal bond is characteristic of metals in solid and liquid state. This is the property of the aggregates of atoms located in close proximity to each other. However, in a vapor state, atoms of metals, as well as all substances, are related to a covalent bond. Pairs of metals consist of individual molecules (single-name and ductomy). The bond strength in the crystal is greater than in the metal molecule, therefore the formation of a metal crystal proceeds with the release of energy.

4. Basic classes of inorganic compounds

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general chemistry
Lectures Tyumen 2005 UDC 546 (075) Sevastyanova G.K., Karnukhova T. M. general chemistry: Lecture course. - Tyumen: Tsogu, 2005. - 210 s.

Basic laws of chemistry
1. The law of preserving the mass of substances (M.V. Lomonosov; 1756): the mass of substances that entered the reaction is equal to the mass of substances formed as a result of the reaction. 2. For

General provisions
According to modern ideas, the atom is the smallest particle of the chemical element, which is the carrier of its chemical properties. The atom is electrically neutral and consists of positively charged

Development of ideas about the structure of an atom
Until the end of the 19th century, most scientists presented an atom as an indecomposable and indivisible particle of the element - the "end node" of matter. It was also considered that atoms are unchanged: atom of this element

Electron state model in atom
In accordance with quantum - mechanical representations, an electron is a formation that behaves both as a particle, and as a wave, i.e. He possesses, like other microparticles, corpuscles

Quantum numbers
For the characteristic of the electron behavior in the atom, quantum numbers were introduced: the main, orbital, magnetic and spin. The main quantum number n determines the electron energy on energy

Electronic configurations (formulas) of elements
Recording the distribution of electrons in the atom in levels, sublayers and orbitals received the name of the electronic configuration (formula) of the element. Usually the electronic formula is provided for the main

The order of filling by electrons levels, sublevels, orbitals in multielectronic atoms
The sequence of filling by electrons levels, sublevels, orbitals in multielectronic atoms determine: 1) the principle of least energy; 2) Clekkovsky rule; 3)

Electronic elements family
Depending on which kind of grain, the latter is filled with electrons, all elements are divided into four types - electronic families: 1. S - elements; filled with electrons S -

The concept of electronic analogues
Atoms of elements with the same filling of the external energy level are the name of electronic analogues. For example:

Periodic law and periodic system of elements D.I. Mendeleev
The most important event of chemistry in the 19th century was the discovery of a periodic law, made in 1869 by a brilliant Russian scientist D. I. Mendeleev. Periodic law In the formulation of D. I. Mendeleev

Structure of the periodic system of chemical elements D. I. Mendeleev
The elements in the periodic system are located in the sequence of increasing the sequence numbers z from 1 to 110. The sequence number of the element Z corresponds to the charge of the kernel of its atom, as well as the number of d

Periodic system D.I. Mendeleev and electronic structure of atoms
Consider the relationship between the position of the element in the periodic system and electronic structure His atoms. Each subsequent element periodic system one electron more than the previous one

The frequency of properties of elements
Since the electronic structure of the elements varies periodically, then, accordingly, the properties of the elements determined by their electronic structure are periodically changed, such as atomic radius, Hene

Theory of the method of valence ties
The method was developed by V. Gateler and J. London. A great contribution to its development was also made by J. Slater and L. Poling. The main provisions of the method valence ties: 1. Chemical Communication

Covalent communication
The chemical bond between atoms carried out by the communal electrons is called covalent. Covalent bond (means - "jointly acting") arises due to the formation of common

Saturability of covalent bond
The saturation of the covalent bond (the valence possibilities of the atom, the maximum valence) characterizes the ability of atoms to participate in the formation of a certain limited number of covalent

The focus of covalent communications
According to the MOV, the most strong chemical bonds occur in the direction of maximum overlapping atomic orbitals. Since atomic orbitals have a definite form, their maximum

Polarity and polarizability of chemical
Covalent bond, in which the common electronic density (common electrons, a binder electron cloud) symmetrical with respect to the nuclei of interacting atoms, is called

Polarity of molecules (types of covalent molecules)
The polarity of the molecule from the polarity of communication should be distinguished. For ductomic molecules of type AV, these concepts coincide, as already shown on the example of the HCl molecule. In such molecules the bigger

Ion communication
In the interaction of two atoms with very different electrical negotiations, the overall pair of electrons can be almost completely shifted to the atom with greater electronegathy. In re

Hydroxide
Among the multi-element compounds, an important group is hydroxides - sophisticated substancescontaining hydroxochroup OH. Some of them (main hydroxides) exhibit the properties of the base - n

Acid
Acids are substances dissociating in solutions to form hydrogen cations and anions of the acid residue (from the position of the theory of electrolytic dissociation). Acid classifies

Basis
The grounds from the standpoint of the theory of electrolytic dissociation are substances that dissociate in solutions to form hydroxide ions OH ~ and metal ions (exception NH4OH

The first law of thermodynamics
The relationship between internal energy, warmth and work establishes the first law (beginning) of thermodynamics. Its mathematical expression: q \u003d du + a, or for nonsense

The thermal effect of the chemical reaction. Thermochemistry. GESS Act
Everything chemical processes accompanied by thermal effects. The thermal effect of the chemical reaction is called the heat released or absorbed as a result of the conversion of the source substances

Entropy
If the system has an external impact on the system, certain changes occur in the system. If, after removing this impact, the system may return to the initial state, the process is

Free Energy Gibbs
All chemical reactions are usually accompanied by a change in both entropy and enthalpy. The relationship between enthalpy and entropy of the system establishes the thermodynamic function of a state that calls

Free energy Helmholts
The direction of flow of isochoretum processes (V \u003d const and T \u003d const) is determined by the change in the free energy of the Helmholtz, which is also called isochloro-isothermal potential (F): DF \u003d

The law of acting masses
The dependence of the chemical reaction rate on the concentration of reactant substances is determined by the law of the existing masses. This law is established by Norwegian scientists Guldberg and Vaage in 1867. He is formula

Dependence of the rate of chemical reaction from temperature
The dependence of the speed of the chemical reaction from temperature is determined by the Vant-Gooff rule and the Arrhenius equation. Rule-Gooff rule: with increasing temperature for every 1

Source Activated Complex Reaction Products
To form an active complex, some energy barrier should be overcome, spending EA energy. This energy is activation energy - some excess energy, compared

Catalyst influence
Changing the reaction rate under the influence of small additives of special substances, the number of which does not change during the process, is called catalysis. Substances that change the speed of the chemical

General ideas about chemical equilibrium. Chemical equilibrium constant
Chemical reactions, as a result of which, at least one of the starting materials is fully consuming, are called irreversible flowing to the end. However, most reactions are

Chemical equilibrium displacement. Principle Le Chatelier
Chemical equilibrium remains unchanged until the parameters are constant, with which

Phase equilibrium. Phase rule Gibbs
Heterogeneous equilibrium associated with the transition of a substance from one phase to another unchanged chemical compositionare called phase. These include equilibrium in the processes are evaporated

You learned how the atoms of metal elements and non-metal elements interact (electrons go from the first to second), as well as the atoms of non-metallulus elements (unpaired electrons of the external electron layers of their atoms are combined into general electronic pairs). Now we will get acquainted with how the atoms of metal elements interact. Metals usually exist in the form of isolated atoms, but in the form of an ingot or metal product. What keeps metal atoms in a single amount?

Atoms of most elements-metals at the outer level contain a small number of electrons - 1, 2, 3. These electrons are easily separated, and atoms turn into positive ions. The detached electrons move from one ion to another, tying them into a single whole.

It is simply impossible to figure out which electron. All unfolded electrons became common. Connecting with ions, these electrons temporarily form atoms, then again come off and connected with another ion, etc. The process is infinitely, which can be portrayed by the scheme:

Consequently, in the volume of metal, atoms are continuously converted into ions and vice versa. They are also called atom ions.

Figure 41 schematically shows the structure of the sodium metal fragment. Each sodium atom is surrounded by eight adjacent atoms.

Fig. 41.
The scheme of the structure of the crystalline sodium fragment

The separated external electrons are freely moving from one formed ion to another, connecting that gluing, the ionic sodium core into one gigantic metal crystal (Fig. 42).

Fig. 42.
Metal communication scheme

Metal communication has some similarity with covalent, as it is based on the generalization of external electrons. However, the formation of a covalent bond is generalized external unpaired electrons of only two neighboring atoms, while all atoms are involved in the establishment of a metallic bond. That is why crystals with a covalent bond of fragile, and with a metal, as a rule, plastic, electrically conductive and have a metal shine.

Figure 43 shows the ancient gold figure of a deer, which is already more than 3.5 thousand years old, but it has not lost characteristic of gold - this very plastic from metals - noble metal gloss.

fig. 43. Golden deer. Vi in. BC e.

Metal bond is characteristic of both pure metals and mixtures of various metals - alloys in solid and liquid states. However, in a vaporous state, metal atoms are connected with a covalent bond (for example, sodium pairs fill the lamps of yellow light to illuminate the streets of large cities). Metal pairs consist of separate molecules (single andomic and ductomy).

The question of chemical connections is the central question of the science of chemistry. You got acquainted with the initial ideas about the types of chemical bond. In the future, you will learn a lot of interesting things about the nature of the chemical connection. For example, in most metals, in addition to metallic communications, there is also a covalent bond that there are other types of chemical ties.

Key words and phrases

1. Metal connection.
2. Atom-ions.
3. Community electrons.

Work with computer

1. Contact your electronic application. Examine the lesson material and execute the proposed tasks.
2. Find online email addresses on the Internet, which can serve as additional sources that reveal the content of keywords and phrase phrases. Invite your assistance to the teacher in the preparation of a new lesson - make a message by keywords and phrases of the next paragraph.

Questions and tasks

1. Metal communication has similarities with a covalent bond. Compare these chemical links among themselves.
2. Metal communication has similarities with ion bond. Compare these chemical links among themselves.
3. How can I increase the hardness of metals and alloys?
4. By the formulas of substances, determine the type of chemical bond in them: VA, Wavr 2, HBR, R 2.

Topic: Chemical Communication Types

Lesson: Metal and Hydrogen Chemical Communications

Metal communication -this is a type of communication in metals and their alloys between atoms or metal ions and relatively free electrons (electron gas) in a crystal lattice.

Metals are chemical elements With low electronegativity, so they easily give their valence electrons. If nemetall is located next to the metal element, the electrons from the metal atom are moving to nonmetal. This type of communication is called ionic (Fig. 1).

When simple substances of metals or them alloy, the situation is changing.

In the formation of molecules, electronic orbitals of metals do not remain unchanged. They interact with each other, forming a new molecular orbital. Depending on the composition and structure of the compound, molecular orbitals can be both close to the totality of atomic orbitals, and significantly differ from them. In the interaction of electronic orbitals of metal atoms, molecular orbitals are formed. Such such that the valence electrons of the metal atom can move freely on these molecular orbital. Full separation, charge, i.e. metal - This is not a totality of cations and floating around electrons. But this is not a totality of atoms, which sometimes go to the cationic form and transmit their electron to another cation. The real situation is a combination of two of these extreme options.

Essence of metallic communication consists In the following: metals atoms give out outer electrons, and some of them turn into positively charged ions. Brooded from atoms lektonsrelatively freely move between the emerging positivemetal ions. A metallic bond arises between these particles, i.e. electrons, as it were, cement positive ions in a metal grid (Fig. 2).

The presence of metallic communication determines the physical properties of metals:

· High plasticity

· Heat and electrical conductivity

· Metal shine

Plastic - This material ability is easy to deform under the action of mechanical load. Metal bond is realized between all metal atoms at the same time, therefore, with mechanical exposure to metal, specific connections are not broken, and only the position of the atom changes. Metal atoms that are not associated with rigid connections among themselves can, as it should slide along the electron gas layer, as it occurs when a single glass is slipped differently with the layer of water between them. Due to this, the metals can be easily deformed or roll into thin foil. The most plastic metals are pure gold, silver and copper. All these metals are in nature in natives in one or another purity. Fig. 3.

Fig. 3. Metals found in native nature

Of these, especially from gold, various decorations are made. Thanks to its amazing plasticity, gold is used when finishing palaces. From it you can roll the foil thickness of only 3. 10 -3 mm. It is called tin gold, applied to plaster, stucco decorations or other items.

Heat and electrical conductivity . The best electric current is carried out copper, silver, gold and aluminum. But since gold and silver - expensive metals, then for the manufacture of cables, cheaper copper and aluminum are used. The most bad electrical conductors are manganese, lead, mercury and tungsten. In tungsten, the electrical resistance is so large that when the electric current is passed, it starts glowing. This property is used in the manufacture of incandescent bulbs.

Body temperature - This is a measure of the energy of the components of its atoms or molecules. Electronic metal gas can rather quickly transmit excess energy from one ion or atom to another. The temperature of the metal is quickly aligned all over the volume, even if the heating comes on one side. It is observed, for example, if you lower the metal spoon in tea.

Metal shine. The gloss is the body's ability to reflect light rays. Silver, aluminum and palladium are highly reflective. Therefore, it is these metals that make a thin layer on the surface of the glass in the manufacture of headlights, spotlights and mirrors.

Hydrogen communications

Consider the boiling and melting temperature of halcogens hydrogen compounds: oxygen, sulfur, selenium and tellurium. Fig. four.

If you mentally extract the direct boiling and melting temperatures of sulfur hydrogen compounds, selenium and tellurium, then we will see that the water melting point must roughly be -100 0 C, and boiling - approximately -80 0 C. This happens because there is between water molecules interaction - hydrogen bond that unites Water molecules In the Association . Extra energy is required to destroy these associates.

The hydrogen bond is formed between the strongly polarized, having a significant proportion of the positive charge at the hydrogen atom and another atom with very high electronegitability: fluorine, oxygen or nitrogen . Examples of substances capable of forming a hydrogen bond are shown in Fig. five.

Consider the formation of hydrogen ties between water molecules. Hydrogen bond is depicted with three dots. The occurrence of hydrogen communication is due to a unique feature of the hydrogen atom. T. K. The hydrogen atom contains only one electron, then when pulling out a total electron pair by another atom, the kernel of the hydrogen atom is taken off, the positive charge of which acts on electronegative elements in the molecules of substances.

Compare properties ethyl alcohol and dimethyl ether. Based on the structure of these substances, it follows that ethyl alcohol can form intermolecular hydrogen bonds. This is due to the presence of hydroxochroup. Dimethyl ether intermolecular hydrogen ties can not form.

Comparish their properties in Table 1.

T KIP., T pl, solubility in water higher in ethyl alcohol. This is a common pattern for substances, between the molecules of which hydrogen communications are formed. These substances are characterized by higher T of instrumentation., T pl, solubility in water and lower volatility.

Physical properties compounds depend on molecular weight Substances. Therefore, to compare the physical properties of substances with hydrogen bonds, it is legitimately only for substances with close molecular weights.

Energy one hydrogen bond about 10 times less covalent bond energy. If there are several functional groups capable of the formation of hydrogen bonds in organic molecules of complex composition, then intramolecular hydrogen bonds (proteins, DNA, amino acids, ortonitrophenol, etc.) can be formed in them. Due to the hydrogen bond, the secondary structure of proteins is formed, a double DNA helix.

Wang der Waalsovoy.

Recall the noble gases. Helium compounds have not yet been received. It is not able to form conventional chemical connections.

With highly negative temperatures, you can get liquid and even hard helium. In a liquid condition, helium atoms are held using electrostatic attraction forces. There are three options for these forces:

· Orientation forces. This is the interaction between two dipoles (HCl)

· Induction attraction. This is the attraction of a dipole and a non-polar molecule.

· Dispersion attraction. This is the interaction between two non-polar molecules (HE). It occurs due to the uneven movement of the electron movement around the kernel.

Summing up lesson

The lesson considers three types of chemical bonds: metallic, hydrogen and van der Waalsovaya. The dependence of physical and chemical properties was explained from different types Chemical bonds in the substance.

Bibliography

1. Rudzitis G.E. Chemistry. Basics of general chemistry. Grade 11: Tutorial for general education institutions: Basic level / G.E. Rudzitis, F.G. Feldman. - 14th ed. - M.: Enlightenment, 2012.

2. Popel P.P. Chemistry: 8 cl.: Textbook for general educational institutions / P.P. Popel, hp skill. - K.: IC "Academy", 2008. - 240 s.: Il.

3. Gabrielyan O.S. Chemistry. Grade 11. A basic level of. 2nd ed., Ched. - M.: Drop, 2007. - 220 s.

Homework

1. Nos. 2, 4, 6 (p. 41) Rudzitis G.E. Chemistry. Basics of general chemistry. Grade 11: Tutorial for general education institutions: Basic level / G.E. Rudzitis, F.G. Feldman. - 14th ed. - M.: Enlightenment, 2012.

2. Why is tungsten used for the manufacture of hairs of incandescent bulbs?

3. What is explained by the absence of hydrogen bonds in the aldehydes molecules?

The purpose of the lesson

• Give an idea of \u200b\u200ba metal chemical connection.

• Learn to record metallic formation schemes.

• Read S. physical properties Metals.

• Learn to clearly divide species chemical ties .

Tasks lesson

• Find out how to interact with each other atoms of metals

• Determine how the metallic connection affects the properties of the substances formed by it

Major terms:

• Electricity - chemical property Atom, which is a quantitative characteristic of an atom ability in a molecule to attract general electronic pairs to itself.
• Chemical communications - The interaction of atoms, due to overlapping electronic clouds of interacting atoms.
• Metal communication - This is a connection in metals between atoms and ions, formed by the establishment of electrons.
• Covalent communication - Chemical bond, formed by overlapping a pair of valence electron. Providing communication electrons are called a common electronic pair. There are 2 types: polar and not polar.
• Ion communication - a chemical bond that is formed between the nonmetal atoms in which the total electronic para Moves to the atom with greater electronegitability. As a result, atoms are attracted as a variene-charged body.
• Hydrogen communications - the chemical bond between the electronegative atom and the hydrogen atom h bound is covalently with another electronegative atom. N, O or F. can act as electronegative atoms. Hydrogen bonds May be intermolecular or intramolecular.

  DURING THE CLASSES

Metal chemical communications

Determine the elements of the not in the "queue". Why?
Ca Fe P K Al Mg Na
What elements from the table Mendeleev are called metals?
Today we learn what properties are from metals, and how they depend on the connection that is formed between the Metal Jones.
To begin with, remember the location of metals in the periodic system?
Metals As we all know usually exist in the form of isolated atoms, but in the form of a piece, ingot or metal product. We find out that it collects metal atoms in a holistic volume.

On the example, we see a piece of gold. And by the way, the unique metal is gold. With pure gold forging, you can make a foil thickness 0.002 mm! Such a shorter foil sheet is almost transparent and has a green shade asking. As a result, it is possible to get a thin foil from the gold ingot of gold, which covers the area of \u200b\u200bthe shaded cortex.
In chemical terms, all metals are characterized by ease of return of valence electrons, and as a result, the formation of positively charged ions and show only positive oxidation. That is why metals are in free state are restlings. The total feature of metal atoms are large sizes in relation to nonmets. External ellektrons are at large distances from the nucleus and therefore weakly connected with it, therefore easily come off.
The atoms of a larger count of metals at the outer level have a small number of electrons - 1,2,3. These electrons easily open and metal atoms become ions.
IM0 - N ē ⇆ Men +
metal atoms - Electrons external. Orbits ⇆ Metal ions

Thus, the flipped electrons can move from one ion to another, they become free to another, and as if communicating them into a single whole. Therefore, it turns out that all the separated electrons are evidence of common, since it cannot be understood which elecotron belongs to which of the metal atoms.
Electrons can condense with cations, then atoms are temporarily formed, from which electrons then come off. This process is constantly and without stopping. It turns out that in the volume of metal, atoms are continuously converted into ions and vice versa. In this case, a small number of common electrons binds a large number of atoms and metal ions. But it is important that the number of electrons in the metal is equal to the general charge of positive ions, Ie, it turns out that in general the metal remains electronic.
Such a process is represented as a model - metal ions are in the cloud from electrons. Such an electronic cloud is called "Electronic Gas".

For example, in this picture, we see how electronics are moving amongmerly inside the Metal crystal lattice.

Fig. 2. Movement of electron

In order to better understand what electronic gas is and how it behaves in the chemical reactions of different metals, let's see an interesting video. (Gold in this video is mentioned solely as a color!)

Now we can write down the definition: a metal communication is a connection in metals between atoms and ions, formed by the establishment of electrons.

Let's compare all kinds of connections that we know and fasten to better distinguish them, let's see the video for this.

Metal communication is not only in pure metal, but also characteristic of mixtures of different metals, alloys in different aggregate states.
Metal communication is essential and determines the main properties of metals.
- electrical conductivity - indiscriminate movement of electrons in the volume of metal. But with a small potential difference so that the electrons move ordered. Metals with better conductivity are AG, CU, AU, AL.
- Plasticity
The links between metal layers are not very significant, it allows you to move layers under load (deforming the metal does not break it). Best deforming metal (soft) AU, AG, CU.
- Metal shine
Electronic gas reflects almost all light rays. That is why pure metals are so shiny and most often have a symbol or white color. Metal are the best reflectors AG, CU, AL, PD, HG

Homework

Exercise 1
Choose formulas substances that have
a) covalent polar communication: CL2, KCL, NH3, O2, MGO, CCL4, SO2;
b) S. ion communication: HCl, KBR, P4, H2S, NA2O, CO2, CAS.
Exercise 2
Disture unnecessary:
a) Cucl2, Al, MGS
b) N2, HCl, O2
c) CA, CO2, Fe
d) MgCl2, NH3, H2

Metal sodium, metal lithium, and the remaining alkaline metals change the color of the flame. Metal lithium and its salt give fire - red color, metallic sodium and sodium salts - yellow, metal potassium and its salt - purple, and rubidium and cesium - also purple, but brighter.

Fig. 4. A piece of metal lithium

Fig. 5. Flame staining with metal

Lithium (LI). Metal lithium, as well as the metallic sodium, belongs to alkaline metals. Both dissolve in water. Sodium, dissolving in water forms a caustic soda - very strong acid. In the dissolution of alkali metals, a lot of heat and gas (hydrogen) is distinguished in water. Such metal is desirable not to touch their hands, as you can burn.

Bibliography

1. Lesson on the topic "Metal Chemical Communication", Teachers of Chemistry Tucht Valentina Anatolyevna MOU "Esenovichskaya Sosh"
2. F. A. Derkach "Chemistry", - scientific and methodological manual. - Kiev, 2008.
3. L. B. Tsvetkov " Inorganic chemistry"- 2nd publication, corrected and complemented. - Lviv, 2006.
4. V. V. Malinovsky, P. G. Nagorno "Inorganic Chemistry" - Kiev, 2009.
5. Glinka N.L. General chemistry. - 27 ed. / Under. ed. V.A. Rabinovich. - L.: Chemistry, 2008. - 704 S.Il.

Edited and sent Lisenak A.V.

Over the lesson worked:

Tucht V.A.

Lisnyak A.V.

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