Talk about solids. Solid bodies can be divided into two large groups: amorphous and crystal. We will share them according to the principle there is an order or not.

IN amorphous substances Molecules are chaotic. There are no patterns in their spatial location. In essence, amorphous substances are very viscous fluids, so viscous that solid.

Hence the name: "A-" - negative particle, "Morphe" - form. Amorphous substances include: glasses, resins, wax, paraffin, soap.

The absence of order in the location of the particles determines the physical properties of amorphous bodies: they do not have fixed melting temperatures. As they heated, their viscosity gradually decreases, and they also gradually pass into a liquid state.

In contrast to amorphous substances exist crystalline. The particles of the crystalline substance are spatially ordered. This is the correct structure of the spatial arrangement of particles in the crystalline substance is called crystal lattice.

In contrast to amorphous bodies, crystalline substances have fixed melting temperatures.

Depending on which particles are in nodes latticeAnd on what connections keep them distinguish: molecular, atomic, ionic and metal grilles.

What is fundamentally important to know what a substance is a crystal lattice? What does it determine? Everything. The structure determines how chemical and physical properties of matter.

The easiest example: DNA. In all organisms on Earth, it is built from the same set of structural components: nucleotides of four types. And what a variety of life. This is all determined by the structure: the order in which these nucleotides are located.

Molecular crystal lattice.

A typical example of water - in solid state (ice). In the nodes of the lattice there are integer molecules. And hold them together intermolecular interactions: Hydrogen bonds, van der Waals forces.

These are weak, so the molecular grille is the most continuingThe melting point of such substances is low.

A good diagnostic sign: if the substance has a liquid or gaseous state under normal conditions and / or has a smell, then most likely this substance has a molecular crystal lattice. After all, the liquid and gaseous state is the consequence of the fact that the molecules on the surface of the crystal are badly kept (the relationship is weak). And they are "blowing". This property is called volatility. And blurred molecules, diffusing in the air reach our sense of smell, which is subjectively felt as the smell.

Molecular crystal lattice have:

1. Some simple substances of non-metals: I 2, P, S (that is, all non-metals, which have no atomic grille).
2. Almost all organic substances (in addition to salting).
3. And as mentioned earlier, substances under normal conditions are liquid or gaseous (being frozen) and / or having a smell (NH 3, O 2, H 2 O, acid, CO 2).

Atomic crystal lattice.

In the nodes of the atomic crystal lattice, in contrast to molecular, are located separate atoms. It turns out that covalent bonds hold the lattice (after all, it is they bind neutral atoms).

A classic example is a standard of hardness strength - diamond (in chemical nature is a simple carbon substance). Communications: covalent notolarySince the grille is formed only carbon atoms.

But, for example, in a quartz crystal (the chemical formula of which SiO 2) has Si and O atoms. Therefore, communication covalent polar.

Physical properties Substances with an atomic crystal lattice:

1. strength, hardness
2. high melting temperatures (refractory)
3. non-volatile substances
4. insoluble (nor in water or other solvents)

All these properties are due to the strength of covalent bonds.

Substances in the atomic crystal grille a bit. There are no special patterns, so they just need to remember:

1. Allotropic carbon modifications (C): diamond, graphite.
2. Bor (B), silicon (Si), Germany (GE).
3. Only two allotropic phosphorus modifications have an atomic crystal lattice: red phosphorus and black phosphorus. (White phosphorus is a molecular crystal lattice).
4. SIC - carborund (silicon carbide).
5. BN - Bora nitride.
6. Silica, rhinestone, quartz, river sand - all these substances have the composition of SiO 2.
7. Corundum, Ruby, sapphire - these substances Al 2 O 3 composition.

Surely the question arises: C is diamond, and graphite. But they are completely different: graphite is opaque, dumps, spends electricity, and the diamond is transparent, not dumpling and does not spend current. They differ in the structure.

And then, and that is an atomic lattice, but different. Therefore, the properties are different.

Ion crystal lattice.

Classic example: Salt Salt: NaCl. In the grille nodes are located separate ions: Na + and Cl -. Holds the lattice electrostatic forces of attraction between ions ("plus" attracts to "minus"), that is ion communication.

Ion crystal lattices are quite strong, but fragile, melting points of such substances are quite high (higher than that of metallic representatives, but lower than that of substances with a nuclear grille). Many soluble in water.

With the definition of the ion crystal lattice, as a rule, there are no problems: where the ion connection is there a ion crystal grille. It: all salts, metal oxides, alkalis (and other major hydroxides).

Metal crystal lattice.

Metal grille is implemented in simple substances of metals. Previously, we said that all the magnificence of the metal communication can only be understood together with the metal crystal lattice. An hour has come.

Main property of metals: electrons on external energy level poorly held, so easy to surrender. Having lost the electron metal turns into a positively charged ion - cation:

Na 0 - 1e → Na +

In the metal crystal lattice, the processes of returns, and the addition of electrons are constantly flowing: an electron is broken from the metal atom in one node. Cation is formed. The eliminated electron is attracted by another cation (or the same): a neutral atom is again formed.

In the nodes of the metal crystal lattice are both neutral atoms and metal cations. And between the nodes travel free electrons:

These free electrons are called electronic gas. They determines the physical properties of simple substances of metals:

1. heat and electrical conductivity
2. metal shine
3. purchase, plasticity

This is a metallic connection: metal cations are attracted to neutral atoms and all this "glued" glued free electrons.

How to determine the type of crystal lattice.

P.S. There is something in the school program and the program of the exam on this topic, with which we do not quite agree. Namely: generalization, that any connection Metal-Nemetall is an ion connection. This assumption is intentionally done, apparently, to simplify the program. But it leads to distortion. The boundary between ion and covalent bond conditional. Each connection has its own percentage of "ionicity" and "covalency". The connection with a low-active metal has a small percentage of "ionicity", it looks more like a covalent. But according to the program of the EGE, it "rounded" towards ion. It breeds, sometimes absurd things. For example, Al 2 O 3 is a substance with an atomic crystal lattice. What ioniness can we talk about here. Only a covalent bond can determine atoms. But according to the Metal-Nemetall standard, we qualify this link as ionic. And the contradiction is obtained: the grille is atomic, and the connection is ionic. This is what it leads excessive simplification.

Solids exist in crystalline and amorphous state and preferably have a crystalline structure. It is distinguished by the correct location of the particles at exactly specific points, is characterized by periodic repeatability in the volume, if it is mentally connected to these points straight - we obtain a spatial frame, which is called the crystal lattice. The concept of "crystalline grille" refers to a geometric image, which describes three-dimensional frequency in placing molecules (atoms, ions) in the crystalline space.

The location points of the particles are called lattice nodes. Inside the frame there are interstal connections. The type of particles and the nature of the connection between them: molecules, atoms, ions - are determined by four such types: ionic, atomic, molecular and metal.

If ions are located in the nodes of the lattice (particles with a negative or positive charge), then this is an ionic crystal lattice characterized by the same relations.

These relationships are very durable and stable. Therefore, substances with such a type of structure have a sufficiently high hardness and density, non-flush and refractory. At low temperatures, they show themselves as dielectrics. However, when laying such compounds, a geometrically correct ion crystal lattice (ion location) is disturbed and the strengths are reduced.

At temperatures close to the melting point, the crystals with ion bond are already capable of carrying out an electric current. Such compounds are easily soluble in water and other liquids, which consist of polar molecules.

The ionic crystal lattice is peculiar to all substances with the ionic type of communication - salts, metal hydroxides, binary compounds of metals with non-metals. It does not matter in space, because each ion is associated immediately with several opponents, the strength of the interaction of which depends on the distance between them (the law of the coulon). Ion-related compounds have a non-elastic structure, they are solids with ion lattices, high polarity, high melting and boiling temperatures, which are electrically conductive in aqueous solutions. There are practically no compounds with ionic connections in pure form.

The ionic crystal lattice is inherent in some hydroxides and oxides of typical metals, salts, i.e. Substances with ionic

In addition to ionic communication in crystals there is a metal, molecular and covalent bond.

Crystals having a covalent bond are semiconductors or dielectrics. Typical examples Atomic crystals are diamond, silicon and germanium.

Diamond is a mineral, allotropic cubic modification (form) of carbon. The crystal lattice of diamond is atomic, very complex. In the nodes of such a lattice there are atoms interconnected by extremely durable covalent bonds. The diamond consists of separate carbon atoms located one by one in the center of the tetrahedron, whose vertices are four closest atoms. Such a lattice is characterized by a granetable cubic that determines the maximum hardness of the diamond and a rather high melting point. There are no molecules in the diamond lattice - and the crystal can be considered as one impressive molecule.

In addition, inherent in silicon, solid Bor, Germany and connections individual elements with silicon and carbon (silica, quartz, mica, river sand, carboorund). In general, representatives with a nuclear grille are relatively few.

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Type of lesson: Combined.

The main objective of the lesson: Give students specific ideas about amorphous and crystalline substances, types of crystalline lattices, establish the relationship between the structure and properties of substances.

Tasks lesson.

Educational: to form the concepts of crystalline and amorphous state of solids, familiarize students with different types of crystalline lattices, establish the dependence of the physical properties of the crystal on the character of the chemical bond in the crystal and the type of crystal lattice, give students the main ideas about the impact of the nature of the chemical bond and the types of crystalline lattices on Properties of a substance, give students an idea of \u200b\u200bthe law of constancy of the composition.

Educational: to continue the formation of the worldview of students, consider the mutual influence of the components of the integer particles of substances, as a result of which new properties appear, to bring up the ability to organize their learning work, follow the rules of work in the team.

Developing: to develop the cognitive interest of schoolchildren using problem situations; Improve the skill of students to establish the causal dependence of the physical properties of substances from the chemical bond and the type of crystal lattice, to predict the type of crystal lattice based on the physical properties of the substance.

Equipment: Periodic System D.I. REMEELEEVA, METALS Collection, non-metals: sulfur, graphite, red phosphorus, oxygen; Presentation of "Crystal Lattices", models of crystal lattices of different types (cook salt, diamond and graphite, carbon dioxide and iodine, metals), samples of plastics and products from them, glass, plasticine, resins, wax, chewing gum, chocolate, computer, multimedia Installation, videos "Renaic acid sublimation".

During the classes

1. Organizational moment.

The teacher welcomes students, records missing.

Then reports theme of the lesson and the purpose of the lesson. Students write the subject of the lesson in the notebook. (Slide 1, 2).

2. Checking homework

(2 student at the board: determine the type of chemical bond for substances with formulas:

1) NaCl, CO 2, I 2; 2) Na, NaOH, H 2 S (write the answer to the board and are included in the survey).

3. Analysis of the situation.

Teacher: What does chemistry study? Answer: Chemistry is a science of substances, their properties and transformations of substances.

Teacher: What is the substance? Answer: Substance is what the physical body consists of. (Slide 3).

Teacher: What aggregate states of substances do you know?

Answer: There are three aggregate states: solid, liquid and gaseous. (Slide 4).

Teacher: Give examples of substances that at different temperatures can exist in all three aggregate states.

Answer: Water. Under normal conditions, water is in liquid state, with a decrease in temperature below 0 0 ° C, the water passes into a solid state - ice, and with an increase in temperature to 100 0 C we will get water vapor (gaseous state).

Teacher (Supplement): Any substance can be obtained in solid, liquid and gaseous form. In addition to water, these are metals, which under normal conditions are in a solid state, when heated, begin to soften, and at a certain temperature (T pl) go into a liquid state - melted. With further heating, to the boiling point, the metals begin to evaporate, i.e. Go to gaseous condition. Any gas can be translated into a liquid and solid state, lowering the temperature: for example, oxygen, which at temperatures (-194 0 C) turns into a liquid blue color, and at temperatures (-218.8 0 C) solidifies in a snow-shaped mass consisting of crystals of blue color. Today in the lesson we will consider the solid state of the substance.

Teacher: Name what solids are on your tables.

Answer: Metals, Plasticine, Salt Salt: NaCl, Graphite.

Teacher: What do you think? Which of these substances are superfluous?

Answer: Plasticine.

Teacher: Why?

Assumptions are made. If students find it difficult, then with the help of the teacher, they come to the conclusion that plasticine, in contrast to metals and sodium chloride, does not have a certain melting point - it (plasticine) gradually softened and goes into a fluid state. Such, for example, chocolate, which melts in the mouth, or chewing gum, as well as glass, plastics, resins, wax (with an explanation, the teacher demonstrates the class samples of these substances). Such substances are called amorphous. (Slide 5), and metals and sodium chloride - crystalline. (Slide 6).

Thus, two types of solids are distinguished : amorphous I. crystal. (slide7).

1) Amorphous substances have no melting point and the location of the particles in them is strictly ordered.

Crystalline substances have a strictly defined melting point and, most importantly, are characterized by the correct location of the particles from which they are constructed: atoms, molecules and ions. These particles are located in strictly defined points of space, and if these nodes connect with straight lines, the spatial frame is formed - crystal cell.

Teacher asks problem issues

How to explain the existence of solids with such various properties?

2) Why are crystalline substances when hitting in certain planes, and the amorphous substances do not possess this property?

Listen to the answers of students and bring them to conclusion:

The properties of substances in solid state depend on the type of crystal lattice (primarily on which particles are in its nodes), which, in turn, is due to the type of chemical bond in this substance.

Check homework:

1) NaCl - ion connection,

CO 2 - Covalent Polar Communication

I 2 - Covalent Nonolaur Communication

2) Na - metal communication

NAON - ion connection between Na + ion - (o and n covalent)

H 2 S - covalent polar

Frontal survey.

• What is the connection called ionic?
• What is the connection called covalent?
• What is the connection called covalent polar? Notolar?
• What is called electronegitability?

Conclusion: Logic sequence is traced, the relationship of phenomena in nature: the structure of the atom-\u003e E-\u003e types of chemical bond-\u003e Type of crystal lattice-\u003e properties of substances . (Slide 10).

Teacher: Depending on the type of particles and on the nature of the relationship between them distinguish four types of crystal lattices: ionic, molecular, atomic and metal. (Slide 11).

The results are issued in the following table sample table for students on the desk. (See Appendix 1). (Slide 12).

Ion crystal lattices

Teacher: What do you think? For substances with what type of chemical communication will be characterized by such a type of lattice?

Answer: ion lattice will be characterized for substances with ion chemical bond.

Teacher: What particles will be in the nodes of the lattice?

Answer: ions.

Teacher: What particles are called ions?

Answer: Jones are particles that have a positive or negative charge.

Teacher: What ions are in composition?

Answer: Simple and complex.

Demonstration - model of the crystal sodium chloride lattice (NaCl).

Teacher's explanation: Sodium and chlorine ions are located in the nodes of the crystal lattice sodium chloride.

In the NaCl crystals of individual sodium chloride molecules. The entire crystal should be considered as a giant macromolecule consisting of an equal number of Na + and Cl -, Na N Cl n ions, where N is a large number.

Communication between ions in such a crystal is very durable. Therefore, substances with an ion lattice have a relatively high hardness. They are refractory, non-volatile, fragile. The melt is conducted by electric current (why?), It is easily dissolved in water.

Ionic compounds are binary compounds of metals (I A and II A), salts, alkali.

Atomic crystal lattices

Demonstration of crystal lattices of diamond and graphite.

Pupils on the table sample graphite.

Teacher: What particles will be in the nodes of the atomic crystal lattice?

Answer: In the nodes of the atomic crystal lattice there are separate atoms.

Teacher: What chemical connection between atoms will arise?

Answer: Covalent chemical bond.

Teacher's explanations.

Indeed, in the nodes of atomic crystalline lattices there are separate atoms associated with covalent bonds. Since atoms, like ions, can be located differently in space, then crystals of different shapes are formed.

Atomic crystal lattice diamond

There are no molecules in these lattices. The whole crystal should be considered as a giant molecule. An example of substances with such a type of crystalline lattice can serve as allotropic carbon modifications: diamond, graphite; as well as boron, silicon, red phosphorus, germanium. Question: What are these substances in composition? Answer: Simple in composition.

Atomic crystal lattices have not only simple, but also complex. For example, aluminum oxide, silicon oxide. All these substances have very high melting temperatures (diamond over 3500 0 c), durable and hard, non-volatile, are practically insoluble in liquids.

Metal crystal lattices

Teacher: Guys, you have a collection of metals on the tables, consider these samples.

Question: What chemical bond is characteristic of metals?

Answer: Metal. Communication in metals between positive ions through common electrons.

Question: What general physical properties for metals is characteristic?

Answer: gloss, electrical conductivity, thermal conductivity, plasticity.

Question: Explain what is the reason for such a number of various substances the same physical properties?

Answer: Metals have a single structure.

Demonstration of models of crystal lattices of metals.

Explanation of the teacher.

Metal tie substances have metal crystal lattices

In the nodes of such lattices there are atoms and positive ions of metals, and in the volume of the crystal, valence electrons are fluid. Electrons electrostatically attract positive metal ions. This explains the stability of the lattice.

Molecular crystal lattices

The teacher demonstrates and calls substances: iodine, sulfur.

Question: What unites these substances?

Answer: These substances are non-metals. Simple in composition.

Question: What is the chemical connection inside the molecules?

Answer: Chemical bond inside covalent molecules is notolar.

Question: What physical properties are characteristic of them?

Answer: volatile, low-melting, poorly soluble in water.

Teacher: Let's compare the properties of metals and non-metals. Pupils respond that the properties are fundamentally different.

Question: Why does the properties of non-metals differ very much from the properties of metals?

Answer: Metal has a metallic connection, and the non-metals are covalent, non-polar.

Teacher: Consequently, the type of lattice is different. Molecular.

Question: What particles are in the nodes of the lattice?

Answer: Molecules.

Demonstration of crystal carbon dioxide and iodine lattices.

Explanation of the teacher.

Molecular crystal grille

As you can see, the molecular crystal lattice may have not only solid simple substances: noble gases, H 2, O 2, N 2, I 2, O 3, white phosphorus P 4, but also sophisticated: solid water, solid chloride and hydrogen sulfide. Most solid organic compounds have molecular crystal lattices (naphthalene, glucose, sugar).

In the nodes of the lattices there are non-polar or polar molecules. Despite the fact that atoms inside molecules are bound by durable covalent bonds, there are weak forces of intermolecular interaction between the molecules themselves.

Output:Substitution substances, have a low hardness, low melting point, volatile, capable of sublimation.

Question : What kind of process is called sublimation or sublimation?

Answer : The transition of a substance from a solid aggregate state immediately into a gaseous, bypassing liquid, called sublimation or sublimation.

Demonstration of experience: the sublimation of benzoic acid (video and video).

Working with a completed table.

Appendix 1. (Slide 17)

Crystal lattices, type of communication and properties of substances

Type of lattice	Types of particles in lattice nodes	Type of communication between particles	Examples of substances	Physical properties of substances
Ionic	Ions	Ionic - communication durable	Salts, halides (IA, IIA), oxides and hydroxides of typical metals	Solid, durable, non-volatile, fragile, refractory, many soluble in water, melted electric current
Atomic	Atoms	1. Covenant non-polar - communication is very durable 2. Covalent Polar - Communication is very durable	Simple substancesbut: diamond (C), graphite (C), Bor (B), silicon (Si). Painst substances: aluminum oxide (Al 2 O 3), silicon oxide (IY) -sio 2	Very solid, very refractory, durable, non-volatile, are not soluble in water
Molecular	Molecules	Between molecules - weak forces of intermolecular attraction, but inside a molecular covalent connection	Solids under special conditions, which, with ordinary gases or liquids (O 2, H 2, CL 2, N 2, BR 2, H 2 O, CO 2, HCl); sulfur, white phosphorus, iodine; Organic substances	Fragile, volatile, loss, capable of sublimation, have a small hardness
Metal	Atom-ions	Metalless strength	Metals and alloys	Dovenki, have glitter, plasticity, heat and electrically conductive

Question: What type of crystal lattice from the above is not found in simple substances?

Answer: ionic crystal lattices.

Question: Which crystal lattices are characteristic of simple substances?

Answer: For simple substances, metallic crystal lattice; For non-metals - atomic or molecular.

Work with the Periodic System D.I. Inendeeva.

Question: Where in the periodic system there are metal elements and why? Non-metal elements and why?

Answer: If you hold a diagonal from Bora to Astat, then elements-metals will be located in the lower left corner from this diagonal. At the last energy level, they contain from one to three electrons. These are elements I A, II A, III A (except for boron), as well as tin and lead, antimony and all elements of side subgroups.

Nemetal elements are in the upper right corner from this diagonal, because At the last energy level contain from four to eight electrons. These are elements IY A, Y A, Yi A, Yii A, Yiii A and Bor.

Teacher: Let's find elements of non-metals, in which simple substances have an atomic crystal lattice (Answer: C, B, SI) and molecular ( Answer: N, S, O , halogens and noble gases ).

Teacher: Word output, how to determine the type of crystal lattice of a simple substance, depending on the position of the elements in the periodic system of D.I. Imeteleev.

Answer: For metal elements that are located in I A, II A, IIIA (except for boron), as well as tin and lead, and all elements of side subgroups in a simple substance type lattice-metal.

For non-metal elements IY A and boron in a simple substance, atomic crystal lattice; And in the elements y a, yi a, yii a, yii a in simple substances, the crystal lattice is molecular.

We continue to work with a table filled.

Teacher: Look carefully on the table. What pattern is traced?

We carefully listen to the answers of students, after which, together with the class, we conclude:

There is the following regularity: if the structure of substances is known, then you can predict their properties, or vice versa: if the properties of substances are known, then the structure can be determined. (Slide 18).

Teacher: Look carefully on the table. What other classification of substances can you offer?

If students find it difficult, then the teacher explains that substances can be divided into substances of molecular and non-ethomicular structure. (Slide 19).

The substances of the molecular structure consist of molecules.

The substances of the neccular structure consist of atoms, ions.

Law of constancy of the composition

Teacher: Today we will get acquainted with one of the main laws of chemistry. This is the law of constancy of the composition, which was opened by the French chemist J.L.prust. The law is valid only for the substances of the molecular structure. Currently, the law is read like this: "Molecular chemical compounds regardless of the method of obtaining them have permanent composition and properties." But for substances with a nelecular structure, this law is not always fair.

The theoretical and practical importance of the law is that, on its basis, the composition of substances can be expressed using the chemical formulas (for many substances of the neo-mecular structure, the chemical formula shows the composition of the non-actual, but conditional molecule).

Output: the chemical formula of the substance contains greater information. (Slide 21)

For example, SO 3:

1. Specific substance - sulfur gas, or sulfur oxide (Yi).

2. Type of substance is complex; Class - oxide.

3. Qualitative composition - consists of two elements: sulfur and oxygen.

4. Quantitative composition - molecule consists of 13 sulfur atom and 3 oxygen atoms.

5. Clear molecular weight - M R (SO 3) \u003d 32 + 3 * 16 \u003d 80.

6. Molar mass - M (SO 3) \u003d 80 g / mol.

7. Many other information.

Consolidation and application of knowledge gained

(Slide 22, 23).

Game in labels - Noliki: Straighten up vertical, horizontal, diagonals of substances having the same crystal lattice.

Reflection.

The teacher asks the question: "Guys, what's new did you know in the lesson?".

Summing up the classes

Teacher: Guys, let's summarize the main results of our lesson - answer questions.

1. What classifications of substances did you know?

2. How do you understand the term crystal lattice.

3. What types of crystal gratings do you now know?

4. What patterns of structure and properties of substances did you know?

5. In what aggregate state of the substance have crystal lattices?

6. What basic law of chemistry did you meet the lesson?

Homework: §22, Abstract.

1. Make a formula of substances: calcium chloride, silicon oxide (IY), nitrogen, hydrogen sulfide.

Determine the type of crystal lattice and try to predict: what should be the melting point of these substances.

2. Creative task -\u003e Create questions to the paragraph.

The teacher thanks for the lesson. Sets the stupid mark.

The substance, as you know, can exist in three aggregate states: gaseous, liquid and solid (Fig. 70). For example, oxygen, which, under normal conditions, is gas, at a temperature of -194 ° C turns into a blue liquid, and at a temperature of -218.8 ° C, it solids in a snow-shaped mass consisting of blue crystals.

Fig. 70.
Aggregate water states

Sliding substances are divided into crystalline and amorphous.

Amorphous substances have no clear melting point - when heated, they gradually soften and go into a fluid state. Amorphous substances include most plastics (for example, polyethylene), wax, chocolate, plasticine, various resins and chewing gum (Fig. 71).

Fig. 71.
Amorphous substances and materials

Crystalline substances are characterized by the correct location of the components of their particles in strictly defined points of space. When connecting these points, the spatial frame is formed by straight lines, called the crystal lattice. The points in which the crystal particles are placed, are called grid nodes.

In the nodes of the imaginary crystal lattice can be monatomic ions, atoms, molecules. These particles perform oscillatory movements. With an increase in the temperature of the scope of these oscillations, it increases, as a rule, to thermal expansion of tel.

Depending on the type of particles located in the assemblies of the crystal lattice, and the nature of the relationship between them is distinguished by four types of crystalline lattices: ionic, atomic, molecular and metal (Table 6).

Table 6.
Position of elements in the periodic system D. I. Mendeleev and types of crystalline decisions of their simple substances

Simple substances formed by the elements not presented in the table have a metal grid.

Ion call crystal lattices, in the nodes of which are ions. They form substances with ion bond, which can be associated both by Na +, Cl - and complex ions, it is. Consequently, ionic crystal lattices have salts, bases (lumps), some oxides. For example, sodium chloride crystal is constructed from alternating positive Na + ions and negative CLs, forming a cube shape (Fig. 72). The links between ions in such a crystal are very durable. Therefore, substances with an ion lattice have relatively high firmness and durability, they are refractory and non-volatile.

Fig. 72.
Ion crystal lattice (sodium chloride)

Atomic is called crystalline lattices, in the nodes of which are separate atoms. In such lattices, atoms are interconnected by very strong covalent bonds.

Fig. 73.
Atomic crystal lattice (diamond)

This type of crystal lattice has a diamond (Fig. 73) is one of the allotropic modifies of carbon. Circled and polished diamonds are called diamonds. They are widely used in jewelry (Fig. 74).

Fig. 74.
Two imperial crowns with diamonds:
a - crown of the British Empire; B - Big Imperial Crown of the Russian Empire

To substances with an atomic crystal lattice include crystalline, silicon and germanium, as well as complex substances, such as silica, quartz, sand, rhinestone, which includes silicon oxide (IV) SiO 2 (Fig. 75).

Fig. 75.
Atomic crystal lattice (silicon oxide (IV))

Most substances with a nuclear crystal lattice have very high melting temperatures (for example, in diamond, it is over 3500 ° C, in silicon - 1415 ° C, in silica - 1728 ° C), they are durable and firm, almost insoluble.

Molecular call crystal lattices, in the nodes of which are molecules. Chemical bonds in these molecules can also be covalent polar (HCL chloride, water H 2 0), and covalent non-polar (N 2 nitrogen, ozone 0 3). Despite the fact that atoms inside molecules are associated with very strong covalent bonds, weak forces of intermolecular attraction act between the molecules themselves. Therefore, substances with molecular crystalline lattices have low hardness, low melting temperatures, volatile.

Examples of substances with molecular crystal lattices are solid water - ice, solid carbon oxide (IV) C) 2 - "Dry Loda" (Fig. 76), solid chloride HCL and hydrogen sulfide H 2 S, solid simple substances formed by one- (noble Gaza: helium, neon, argon, krypton), two- (hydrogen H 2, oxygen O 2, chlorine CL 2, nitrogen N 2, iodine 1 2), three- (ozone O 3), four- (white phosphorus p 4 ), octate (sulfur S 7) molecules. Most solid organic compounds Have molecular crystalline lattices (naphthalene, glucose, sugar).

Fig. 76.
Molecular crystal lattice (carbon dioxide)

Metal crystalline grilles have metallic tie substances (Fig. 77). In the nodes of such lattices there are atoms and ions (then atoms, then ions in which metal atoms easily convert, giving their external electrons to total use). Such an internal structure of metals determines their characteristic physical properties: forging, plasticity, electric and thermal conductivity, metal shine.

Fig. 77.
Metal crystal lattice (iron)

Laboratory experience number 13
Acquaintance with the collection of substances with different types of crystal lattice. Making models of crystal lattice

Check out the collection of substances issued to you. Write down their formulas, characterize physical properties and based on the type of crystal lattice based on them.

Collect the model of one of the crystal lattice.

For substances having a molecular structure, just open by the French chemist J. L. Proustom (1799-1803) the law of constancy of the composition. Currently, this law is as follows:

The Prut law is one of the main laws of chemistry. However, for substances of a non-ethnicular structure, for example, ionic, this law is not always fair.

Key words and phrases

1. Solid, liquid and gaseous state of the substance.
2. Sliding substances: amorphous and crystalline.
3. Crystal lattices: ionic, atomic, molecular and metal.
4. Physical properties of substances with different types of crystal lattice.
5. The law of constancy of the composition.

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. What aggregate state will be oxygen at -205 ° C?
2. Remember the work of A. Belyaeva "Selener of air" and characterize the properties of solid oxygen using its description given in the book.
3. What type of substances (crystalline or amorphous) are plastics? What properties of plastics underlie their industrial use?
4. What type of crystal diamond grille is? List the physical properties characteristic of diamond.
5. What type of crystal iodine grille belongs to? List the physical properties typical for iodine.
6. Why changes the melting point of metals in very wide limits? To prepare an answer to this question, use additional literature.
7. Why is a silicon product split into pieces when hitting, and the lead product is only flattened? In which of the specified cases, the destruction of the chemical bond occurs, and in what - no? Why?

The links between ions in the crystal are very durable and stable. Therefore, the substance with the ion lattice has high hardness and durability, refractory and non-volatile.

Substances with an ion crystal lattice have the following properties:

1. relatively high hardness and strength;

2. fragility;

3. heat resistance;

4. refractory;

5. Netty.

Examples: Salts - sodium chloride, potassium carbonate, base - calcium hydroxide, sodium hydroxide.

4. The mechanism for the formation of a covalent bond (exchange and donor-acceptor).

Each atom seeks to complete its external electronic level to reduce potential energy. Therefore, the kernel of one atom is attracted to itself the electronic density of the other atom and, on the contrary, there is an imposition of electronic clouds of two adjacent atoms.

Demonstration of appliqués and schemes for the formation of a covalent non-polar chemical bond in a hydrogen molecule. (Students write and sketch diagrams).

Conclusion: The connection between atoms in the hydrogen molecule is carried out due to the general electron pair. Such a connection is called covalent.

What connection is called covalent nepolyarn? (Tutorial page 33).

Compilation of electronic formulas of molecules of simple substances of non-metals:

Ci Ci - electronic formula of the chlorine molecule,

Ci - Ci is the structural formula of the chlorine molecule.

N n is the electronic formula of nitrogen molecule,

N ≡ N is the structural formula of the nitrogen molecule.

Electricity. Covalent polar and non-polar communication. Covalent bonds.

But molecules can form different non-metal atoms and in this case the general electronic pair will be shifted to a more electronegative chemical element.

Explore the textbook material on page 34

Conclusion: Metals have a lower electronegability value than non-metals. And between them it is very different.

Demonstration of the polar covalent bond formation scheme in the chloride molecule.

The total electron pair is shifted to chlorine as the electronegative. So this is a covalent connection. It is formed by atoms, the electronegativity of which is slightly different, therefore it is a covalent polar communication.

Compilation of electronic formulas of molecules of iodorodor and water:

H j - electronic formula of iodorode molecule,

H → J is the structural formula of the iodorod molecule.

H O - electronic formula of water molecule,

N → O is the structural formula of the water molecule.

Independent work with a textbook: To write down the definition of electronegativity.

Molecular and atomic crystal lattices. Properties of substances with molecular and atomic crystal lattices

Independent work with a textbook.

Questions for self-control

Atom, which chemical element has a charge of the core +11

- Write the scheme of the electronic structure of the sodium atom

- External layer completed?

- How to achieve the completion of the filling of the electronic layer?

- make an electron recoil scheme

- Compare the structure of the atom and sodium ion

Compare the structure of the atom and an inert gas of neon.

Determine the atom, of which element with the number of protons 17.

- Record the circuit of the electronic structure of the atom.

- Is the layer completed? How to achieve this.

- Create a scheme for completing the electronic chlorine layer.

Task in groups:

1-3 Group: Covenate electronic and structural formulas of substances molecules and specify the bR 2 bond type; NH 3.

4-6 groups: Consider electronic and structural formulas of molecules of substances and specify the type of communication F 2; HBr.

Two student work at the additional board with the same task for the sample to self-test.

Oral survey.

1. Give the definition of the concept of "Electricity".

2. What depends the electronenence of the atom?

3. How does the electronencence of atoms of elements change in periods?

4. How does the electrothitality of the elements atoms change in the main subgroups?

5. Compare the electronegability of metals and nonmetal atoms. Whether ways are distinguished by the completion of the outer electron layer characteristic of metals and non-metal atoms? What are the reasons for this?

7. What chemical elements are able to give electrons, take electrons?

What happens between atoms at the return and adoption of electrons?

What are the particles formed from the atom as a result of the return or addition of electrons?

8. What will happen when a metal and non-metal atoms meet?

9. How is ion connection formed?

10. Chemical bond formed by the formation of general electronic pairs is called ...

11. Covalent connection is ... and ...

12. What is the similarity of covalent polar and covalent non-polar communication? What does the polarity of communication depend on?

13. What is the difference in covalent polar and covalent non-polar communication?

Plan of classes number 8

Discipline: Chemistry.

Subject:Metal connection. Aggregate states and hydrogen bond .

Objective: To form a concept about chemical bonds on an example of a metallic connection. To achieve an understanding of the communication mechanism.

Planned results

Subject: forming a horizon and functional literacy of a person to solve practical problems; ability to process, explain the results; readiness and ability to apply cognition methods in solving practical problems;

MetaPered: Use of various sources to obtain chemical information, the ability to estimate its accuracy to achieve good results in the professional field;

Personal: the ability to use the achievements of modern chemical science and chemical technologies to increase their own intellectual development in the selected professional activity;

Time rate:2 hours

Type of classes:Lecture.

Plan lesson:

1. Metal connection. Metal crystal lattice and metallic chemical bond.

2. Physical properties of metals.

3. Aggregate states of substances. Transition of a substance from one aggregate state to another.

4. Hydrogen communications

Equipment: Periodic system chemical elements, crystal lattice, distribution material.

Literature:

1. Chemistry grade 11: studies. For general education. organizations G.E. Rudzitis, F.G. Feldman. - M.: Enlightenment, 2014. -208 C.: Il ..

2. Chemistry for professions and specialties of technical profile: a textbook for the stud. media institutions. prof. Education / O.S. Gabrilyan, I.G. Outrium. - 5 - ed., Even. - M.: Publishing Center "Academy", 2017. - 272c., With color. Il.

Lecturer: Tubaltseva Yu.N.