Nemetalla - Elements with the 14th to the 16th Mendeleev Table Group. They almost do not conduct electricity and heat. Non-metals are very fragile and practically not bending and any other deformations. They can exist in 2 of the 3 states of matter at room temperature: gas (for example, oxygen) and solids (for example, carbon). Non-metals, do not possess a metal shine and do not reflect the light.

The interaction of non-metals with simple substances.

1. Non-metallic interaction with metals:

2NA + CL 2 \u003d 2NACL,

Fe + S \u003d FES,

6Li + N 2 \u003d 2Li 3 N,

2CA + O 2 \u003d 2CAO.

in such cases, non-metals exhibit oxidative properties (electrons are taken, forming negatively charged particles).

2. The interaction of non-metals with other non-metals:

• interacting with hydrogen, almost all non-metals exhibits oxidative properties, while forming volatile hydrogen compounds - covalent hydrides:

3H 2 + N 2 \u003d 2NH 3,

H 2 + BR 2 \u003d 2HBR;

• interacting with oxygen, all non-metals, except fluoride, exhibit replacement properties:

S + O 2 \u003d SO 2,

4p + 5O 2 \u003d 2p 2 O 5;

• when interacting with fluorine fluorine is an oxidizing agent, and oxygen - reducing agent:

2F 2 + O 2 \u003d 2of 2;

• non-metals interact with each other, the more electronegative metal plays the role of the oxidant, less electronegative - the role of the reducing agent:

S + 3F 2 \u003d SF 6,

Lecture 3. Nemmetalla

1. general characteristics Elements Nemmetalov

Chemical elements-non-metals are only 16, but two of them, oxygen and silicon make up 76% of the mass of the earth's crust. Non-metals are 98.5% of the mass of plants and 97.6% of the mass of man. Of carbon, hydrogen, oxygen, sulfur, phosphorus and nitrogen consist of all the most important organic substancesThey are elements of life. Hydrogen and helium are the main elements of the universe of them consist of all space objects, including our sun. Without unmetall connections it is impossible to present our lives, especially if you remember that vital chemical compound - Water - consists of hydrogen and oxygen.

Non-metals are chemical elements whose atoms take electrons to complete the external energy level, while forming negatively charged ions.

Almost all non-metals have relatively small radii and a large number of electrons on the external energy level From 4 to 7, they are characterized by high electronegability and oxidative properties.

1.1. The position of non-metal elements in the periodic system of chemical elements of Mendeleev

If in the periodic system to spend a diagonal from boron to Astatu, then elements-non-metal elements will be on the right of the diagonal, and the metal from the left, it is the elements of all side subgroups, lanthanoids and actinoids. Elements located near the diagonal, for example, beryllium, aluminum, titanium, germanium, antimony, have a dual character and belong to metalloids. Non-metal elements: S-element - hydrogen; P-elements 13 group - boron; 14 groups - carbon and silicon; 15 groups - nitrogen, phosphorus and arsenic, 16 groups - oxygen, sulfur, selenium and tellurium and all elements 17 groups - fluorine, chlorine, bromine, iodine and astat. The elements 18 of the group are inert gases, occupy a special position, they have a fully completed outer electron layer and occupy an intermediate position between metals and non-metals. They are sometimes referred to nonmetallam, but formally, in physical signs.

1.2. Electronic structure of non-metal elements

Almost all non-metallyle elements at the external energy level have a large number of electrons - from 4 to 7. The element of the boron is an analogue of aluminum, it has only 3 electrons at the external energy level, but it has a small radius, it has a firmly holding its electrons and has the properties of non-metal. Especially mention the electronic structure of hydrogen. This is an s-element, but it is quite easily taken by one electron, forms a hydride ion and shows the oxidative properties of the metal.

Electronic configurations of valence electrons elements-non-metals are shown in the table:

1.3. Patterns in changing the properties of non-metal elements

Consider some patterns in changing the properties of non-metal elements belonging to one period and one group on the basis of the structure of their atoms.

In the period:

The charge of the nucleus increases,

The radius of the atom decreases

The number of electrons in the external energy level increases,

Electricity increases,

Oxidative properties are enhanced,

Non-metallic properties are enhanced.

In a group:

The charge of the nucleus increases,

The radius of the atom increases

The number of electrons in the external energy level does not change,

Electricity decreases,

Oxidative properties weaken,

Non-metallic properties weaken.

Thus, than the right and above it is an element in the periodic system, the brighter its non-metallic properties are expressed.

- This is the ability to polarize chemical bond, to delay the general electronic pairs.
Nemetallam include 22 elements.
The position of non-metallic elements in the periodic system of chemical elements

Group	I.	III	IV	V.	VI	VII	VIII.
1st period	N.						He.
2nd period		IN	FROM	N.	O.	F.	Ne
3rd period			SI	P.	S.	Cl.	AR
4th period				As	SE	Br.	Kr.
5th period					TE	I.	Xe.
6th period						AT.	RN.

As can be seen from the table, non-metallic elements are mainly located in the right upper part of the periodic system.

The structure of atoms Nemetalles

A characteristic feature of non-metals is greater (compared to metals) the number of electrons at the external energy level of their atoms. This determines their greater ability to attach additional electrons and manifest higher oxidative activity than from metals. Especially strong oxidative properties, i.e. the ability to attach electrons, exhibit non-metals in the 2nd and 3rd periods of VI-VII groups. If you compare the location of electrons by orbitals in fluorine atoms, chlorine and other halogen, then it can be judged about their distinctive properties. There is no fluorine atom of fluoride orbital. Therefore, fluorine atoms can show only valence I and the degree of oxidation - 1. The strongest oxidant is fluorine . In the atoms of other halogen, for example, in the chlorine atom, there are free D-orbitals at the same energy level. Due to this, the breaking of electrons can occur in three different ways. In the first case, chlorine can manifest the degree of oxidation +3 and form the HCLO 2 chloride, which corresponds to the chlorite salt, for example, potassium chlorine KCLO 2. In the second case, chlorine may form compounds in which the degree of chlorine oxidation is +5. Such compounds include chlorinated HCLO 3 acid and its salts - chlorates, such as potassium chlorat KCLO 3 (Bertolet Salt). In the third case, chlorine shows the degree of oxidation +7, for example, in chloroic acid HCLO 4 and in its salts, docks (in potassium perchlorate KCLO 4).

The buildings of non-metal molecules. Physical properties Nemmetalov

In the gaseous state at room temperature are:

· hydrogen - H 2;

· nitrogen - N 2;

· oxygen - O 2;

· fluorine - f 2;

· chlorine - Ci 2.

And inert gases:

· helium - he;

· neon - ne;

· argon - Ar;

· krypton - Kr;

· xenon - XE;

· radon - Rn).

IN liquid - Brom - Br.
IN solid:
· Tellur - TE;

· iodine - i;

· aSTAT - AT.

It's much richer in non-metals and a range of colors: red - phosphorus, brown - in bromine, yellow - in sulfur, yellow-green - in chlorine, purple - in the vapor of iodine, etc.
The most typical nonmetals have a molecular structure, and less typical - non-elastic. This explains the difference between their properties.
Composition and properties of simple substances - non-metals
Nonmetals form both monatomic and ductomic molecules. TO monatomic Nemmetallam include inert gases, practically not reacting even with the most active substances. The inert gases are located in the VIII group of the periodic system, and the chemical formulas of the corresponding simple substances are as follows: HE, NE, AR, KR, XE and RN.
Some nonmetals form dihomatomy molecules. These are H 2, F 2, CL 2, BR 2, CL 2 (elements VII of the periodic system group), as well as oxygen O 2 and nitrogen N 2. Of trehatomic Molecules consists of ozone gas (O 3). For substances of non-metals, which are in a solid state, make a chemical formula quite difficult. Carbon atoms in graphite are connected to each other in different ways. Select a separate molecule in the above structures is difficult. When writing the chemical formulas such as substances, as in the case of metals, assumes are introduced that such substances consist only of atoms. Chemical formulasAt the same time, recorded without indexes: C, Si, S, etc. Such simple substancesAs ozone and oxygen having the same qualitative composition (both consist of the same element - oxygen), but differ in the number of atoms in the molecule, have different properties. So, the oxygen smell does not have, while ozone has a sharp smell that we feel during a thunderstorm. The properties of solid non-metals, graphite and diamonds, which also have the same quality composition, but the different structure is sharply different (fragile graphite, solid diamond). Thus, the properties of the substance are determined not only by its qualitative composition, but also how many atoms are contained in the substance molecule and how they are interconnected. Nonmetals in the form of simple bodies are in a solid or gaseous state (excluding bromine - liquid). They do not have physical properties inherent in metals. Solid nonmetals do not have a glitter characteristic of metals, they are usually fragile, poorly spend electricity And heat (except graphite). The crystalline boron in (as well as crystalline silicon) has a very high melting point (2075 ° C) and a large hardness. The electrical conductivity of the boron with an increase in temperature increases greatly, which makes it possible to widely apply it in semiconductor techniques. Supplement boron to steel and to aluminum, copper, nickel alloys, etc. improves their mechanical properties. Borides (boron compounds with some metals, for example with titanium: TIB, TIB 2) are necessary in the manufacture of parts of jet engines, gas turbine blades. As can be seen from the scheme 1, carbon - with, silicon - Si, Bor - B have similar structure And have some common properties. As simple substances, they are found in two modifications - in crystalline and amorphous. Crystalline modifications of these elements are very solid, with high melting temperatures. Crystalline silicon has semiconductor properties. All these elements form compounds with metals - carbides, silicides and borides (CAC 2, Al 4 C 3, Fe 3 C, Mg 2 Si, TIB, TIB 2). Some of them have a greater hardness, such as Fe 3 C, TIB. Calcium carbide is used to obtain acetylene.

The overall characteristic of non-metals.

Nemetalla - Chemical elements that form simple bodies that do not have properties characteristic of metals. The high-quality characteristic of non-metals is electronegativity.

Electricity - This is the ability to polarize chemical bond, to delay the general electronic pairs.

Nemetallam include 22 elements.

The position of non-metallic elements in the periodic system of chemical elements

1st period
2nd period
3rd period
4th period
5th period
6th period

As can be seen from the table, non-metallic elements are mainly located in the right upper part of the periodic system.

The structure of atoms Nemetalles

A characteristic feature of non-metals is greater (compared to metals) the number of electrons at the external energy level of their atoms. This determines their greater ability to attach additional electrons and manifest higher oxidative activity than from metals. Especially strong oxidative properties, i.e. the ability to attach electrons, exhibit non-metals in the 2nd and 3rd periods of VI-VII groups. If you compare the location of electrons by orbitals in fluorine atoms, chlorine and other halogen, then it can be judged about their distinctive properties. There is no fluorine atom of fluoride orbital. Therefore, fluorine atoms can show only valence I and the degree of oxidation - 1. The strongest oxidant is fluorine. In the atoms of other halogen, for example, in the chlorine atom, there are free D-orbitals at the same energy level. Due to this, the breaking of electrons can occur in three different ways. In the first case, chlorine can manifest the degree of oxidation +3 and form the HCLO 2 chloride, which corresponds to the chlorite salt, for example, potassium chlorine KCLO 2. In the second case, chlorine may form compounds in which the degree of chlorine oxidation is +5. Such compounds include chlorinated HCLO 3 acid and its salts - chlorates, such as potassium chlorat KCLO 3 (Bertolet Salt). In the third case, chlorine shows the degree of oxidation +7, for example, in chloroic acid HCLO 4 and in its salts, docks (in potassium perchlorate KCLO 4).

The buildings of non-metal molecules. Physical properties Nemmetalov

In the gaseous state at room temperature are:

hydrogen - H 2;

nitrogen - N 2;

oxygen - O 2;

fluorine - f 2;

chlorine - Ci 2.

And inert gases:

helium - he;

neon - ne;

argon - Ar;

krypton - Kr;

xenon - XE;

radon - Rn).

In a liquid - bromine - Br.

In solid:

• carbon - C;

  silicon - Si;

  phosphorus - p;

• arsenic - as;

  selenium - SE;

  tellur - TE;

• aSTAT - AT.

It's much richer in non-metals and a range of colors: red - phosphorus, brown - in bromine, yellow - in sulfur, yellow-green - in chlorine, purple - in the vapor of iodine, etc.

The most typical nonmetals have a molecular structure, and less typical - non-elastic. This explains the difference between their properties.

Composition and properties of simple substances - non-metals

Nonmetals form both monatomic and ductomic molecules. TO monatomic Nemmetallam include inert gases, practically not reacting even with the most active substances. The inert gases are located in the VIII group of the periodic system, and the chemical formulas of the corresponding simple substances are as follows: HE, NE, AR, KR, XE and RN.

Some nonmetals form dihomatomy molecules. These are H 2, F 2, CL 2, BR 2, CL 2 (elements VII of the periodic system group), as well as oxygen O 2 and nitrogen N 2. Of trehatomic Molecules consists of ozone gas (O 3). For substances of non-metals, which are in a solid state, make a chemical formula quite difficult. Carbon atoms in graphite are connected to each other in different ways. Select a separate molecule in the above structures is difficult. When writing the chemical formulas such as substances, as in the case of metals, assumes are introduced that such substances consist only of atoms. Chemical formulas, while recorded without indexes: C, SI, S, etc. Such substances such as ozone and oxygen having the same quality composition (both consist of the same element - oxygen), but differing by the number Atoms in the molecule, have different properties. So, the oxygen smell does not have, while ozone has a sharp smell that we feel during a thunderstorm. The properties of solid non-metals, graphite and diamonds, which also have the same quality composition, but the different structure is sharply different (fragile graphite, solid diamond). Thus, the properties of the substance are determined not only by its qualitative composition, but also how many atoms are contained in the substance molecule and how they are interconnected. Nonmetals in the form of simple bodies are in a solid or gaseous state (excluding bromine - liquid). They do not have physical propertiesinherent in metals. Solid nonmetals do not have a glitter characteristic of metal, they are usually fragile, poorly conduct electric current and heat (except graphite). The crystalline boron in (as well as crystalline silicon) has a very high melting point (2075 ° C) and a large hardness. The electrical conductivity of the boron with an increase in temperature increases greatly, which makes it possible to widely apply it in semiconductor techniques. Supplement boron to steel and to aluminum, copper, nickel alloys, etc. improves their mechanical properties. Borides (boron compounds with some metals, for example with titanium: TIB, TIB 2) are necessary in the manufacture of parts of jet engines, gas turbine blades. As can be seen from the scheme 1, carbon - C, silicon - Si, Bor - B have a similar structure and have some common properties. As simple substances, they are found in two modifications - in crystalline and amorphous. Crystalline modifications of these elements are very solid, with high melting temperatures. Crystalline silicon has semiconductor properties. All these elements form compounds with metals - carbides, silicides and borides (CAC 2, Al 4 C 3, Fe 3 C, Mg 2 Si, TIB, TIB 2). Some of them have a greater hardness, such as Fe 3 C, TIB. Calcium carbide is used to obtain acetylene.

Chemical properties Nemmetalov

In accordance with the numerical values \u200b\u200bof relative electries-negativeness, non-metal oxidation abilities increase in the following order: Si, B, H, P, C, S, I, N, CL, O, F.

Nonmetals like oxidizing agents

The oxidative properties of non-metals are manifested in their interaction:

with metals: 2NA + CL 2 \u003d 2NACL;

with hydrogen: H 2 + F 2 \u003d 2HF;

with non-metals, which have lower electronegitability: 2p + 5s \u003d p 2 S 5;

with some complicated substances: 4NH 3 + 5O 2 \u003d 4NO + 6H 2 O,

2FeCl 2 + Cl 2 \u003d 2 FECL 3.

Nonmetals as reducing agents

All non-metals (except fluorine) exhibit replacement properties when interacting with oxygen:

S + O 2 \u003d SO 2, 2H 2 + O 2 \u003d 2H 2 O.

Oxygen in the compound with fluorine may also show a positive degree of oxidation, i.e., be a reducing agent. All other non-metals exhibit replacement properties. For example, chlorine directly with oxygen is not connected, but an indirect way to obtain its oxides (Cl 2 O, CLO 2, CL 2 O 2), in which chlorine shows a positive degree of oxidation. Nitrogen at high temperature is directly connected to oxygen and shows rehabilitation properties. Even easier with oxygen reacts sulfur.

Many non-metals exhibit replacement properties when interacting with complex substances:

Zno + C \u003d Zn + CO, S + 6HNO 3 concrease \u003d H 2 SO 4 + 6NO 2 + 2H 2 O.

There are also such reactions in which the same nonmetall is both the oxidizing agent and the reducing agent:

Cl 2 + H 2 O \u003d HCl + HCLO.

Fluorine is the most typical nonmetall, which is uncharacteristic reducing properties, i.e. the ability to give electrons in chemical reactions.

Unmetalov compounds

Nonmetals can form compounds with different intramolecular bonds.

Types of unmetall connections

General formulas for hydrogen compounds by groups of periodic system of chemical elements are shown in the table:

Non-volatile hydrogen compounds				Volatile hydrogen compounds

With metals, hydrogen forms (for some exception), non-volatile compounds that are solid substances of a non-ethics. Therefore, their melting points are relatively high. With nonmetallaces, hydrogen forms volatile compounds of the molecular structure (for example, HF fluoride, hydrogen sulfide H 2 S, ammonia NH 3, methane CH 4). Under normal conditions, these are gases or volatile fluids. When dissolved in water, hydrogen compounds of halogens, sulfur, selenium and tellurium form acids of the same formula as the hydrogen compounds themselves: HF, HCl, HBr, Hi, H 2 S, H 2 SE, H 2 TE. When the ammonia water is formed in the water dissolution, ammonia water is formulated, usually denoted by the NH 4 OH formula and called ammonium hydroxide. It is also denoted by the NH 3 ∙ H 2 O formula and is called ammonia hydrate.

Non-metal oxygen form acid oxides. In one oxides, they exhibit the maximum degree of oxidation equal to the number of the group (for example, SO 2, N 2 O 5), and others are lower (for example, SO 2, N 2 O 3). Acid oxide The acid corresponds to, and of the two oxygen acids of one non-metallol, the one in which it exhibits a higher degree of oxidation. For example, HNO 3 nitric acid is stronger than nitrogenous HNO 2, and sulfuric acid H 2 SO 4 is stronger than sulfur H 2 SO 3.

Characteristics oxygen compounds Nemmetalov

The properties of higher oxides (i.e. oxides, which include an element of this group with the highest degree of oxidation) in the periods from left to right, gradually change from the main to acid.

In groups from top to bottom, the acidic properties of higher oxides are gradually weakened. This can be judged by the properties of acids corresponding to these oxides.

The increase in the acidic properties of the highest oxides of the corresponding elements in the periods from left to the right is due to the gradual increase in the positive charge of the ions of these elements.

In the main subgroups of the periodic system of chemical elements in the direction from top to bottom, the acid properties of higher oxides of non-metals are reduced.

Halogens.

The structure of atoms halogen

The halogens include elements of the VIII group of the periodic system, the atoms of these elements contain seven electrons at the external energy level and until it is lacking only one electron, so halogens exhibit bright oxidative properties. In a subgroup with an increase in the sequence number, these properties are reduced due to an increase in the radius of atoms: the rehabilitation properties of them increase from fluorine to Astanat. Similarly, the value of the relative electronenence of halogen is reduced. As the most electronegative element, fluorine in connections with other elements exhibits a constant degree of oxidation -1 . The remaining halogens can exhibit both this degree of oxidation in compounds with metals, hydrogen and less electronegative elements and positive odd degrees of oxidation from +1 before +7 In compounds with more electronegative elements: oxygen, fluorine.

Simple substances halogens and their properties

Chlorine, bromine and iodine in glass vessels

Describing simple substances - halogen, it is necessary to recall the main theoretical information on the types of chemical bond and the crystalline structure of the substance. In diatomic molecules of halogen atoms are associated with a covalent non-polar bond D · · g or Mr. and have a molecular crystal lattice.

Under normal conditions F. 2 - bright yellow, with orange tint gas, Cl. 2 - yellow-green poisonous gas with a characteristic indulgeous smell, Br. 2 - the volatile brown liquid (the bromine pairs are very poisonous, burns bromom very painful and do not heal for a long time), and I. 2 - solid crystalline substance capable of sublimation. In row F. 2, Cl 2 , Br. 2 , I. 2 - The density of simple substances is growing, and the intensity of the color increases. Consequently, in the change in the properties of atoms and simple substances - halogen, the same pattern is manifested: with an increase in the sequence number, non-metallic properties weaken, and metal - enhanced.

Chemical properties of halogen

The interaction of halogens with metals with the formation of halides:

2NA + i 2 - 2NA +1 i -1 (sodium iodide);

2Al + 3i 2 \u003d 2Al +3 i 3 -1 (aluminum iodide);

2AL + 3Br 2 \u003d 2AL +3 br 3 -1 (aluminum bromide).

In the reactions of metals of side subgroups (transition metals) with halogens, halides are formed with a large degree of metal oxidation, for example:

2fe + 3Cl 2 \u003d 2FECl 3,

but 2nsl + Fe \u003d FECL 2 + H 2.

The interaction of halogens with hydrogen with the formation of halogen breeders (communication type - covalent polar, type of grid - molecular). Comparison of the speed of chemical reactions of different halogens with hydrogen makes it possible to repeat its dependence on the nature of the reacting substances. So, fluorine has so much reaction rate, which interacts with hydrogen with an explosion, even in the dark. Chlorine's reaction with hydrogen under normal conditions is slow and only when igniting or illumination, its speed increases many times (explosion occurs). It is even slower to interact with hydrogen in bromine and iodine, and the latter reaction is already becoming an endothermic character:

Only fluorine interacts with hydrogen irreversible, the remaining halogens depending on the conditions can also give a reversible reaction.

The aqueous solutions of halogen hydrogen sodes are acids: HF - fluoride hydrogen (plumbing), HCl - chloride (hydrogen), HBr - bomomomodnaya, Hi - iodium hydrogen.

Halogens interact with water:

2F 2 + 2N 2 O \u003d 4HF + O 2

Water in fluorine is burning, oxygen is not the cause, but by the consequence of burning, speaking in an unusual role of the reducing agent.

To characterize the ability of some halogen (not atoms of halogen, and simple substances) to the oss of others from solutions of their compounds, the "range of activity" of halogens, which is written as follows:

F 2\u003e SL 2\u003e BR 2\u003e I 2,

i.e. oxidative properties decrease.

So, chlorine displaces the bromine and iodine (but not fluorine), and the bromine is able to oust only iodine from solutions of the corresponding salts:

2NABR + CL 2 \u003d 2NAsl + Br 2

2ki + br 2 \u003d 2kvr + i 2.

Biological significance and the use of halogen

Fluorineplays a very important role in the life of plants, animals and man. Without fluorine, the development of the bone skeleton and especially the teeth is impossible. The fluorine content in the bones is 80-100 mg per 100 g of dry matter. In the enamel fluorine is present in the form of compound Ca 4 F 2 (PO 4) 2 and gives it hardness and whiteness. With a lack of fluorine in the human body, a dental tissue is leshed (caries), and its excess contributes to the disease of the teeth with fluorosis. The daily need of a person in fluorine is 2-3 mg. Chlorine(chlorine ion) is more important for animal and human life than for plants. It is part of the kidneys, lungs, spleen, blood, saliva, cartilage, hair. Chlorine ions regulate blood buffer system. Sodium chloride is an integral part of blood plasma and spinal fluid and participates in the regulation of water exchange in the body. Free hydrochloric acid is part of the gastric juice of all mammals and is actively involved in digestion. A healthy person is contained in the stomach of 0.2-0.3% hydrochloric acid. The lack of chlorine in the body leads to tachycardia, decrease in blood pressure, seizures. A sufficient amount of chlorine is contained in vegetables such as celery, radishes, cucumbers, white cabbage, dill, pepper, onions, artichoke. Brominealso among the necessary trace elements and is most of all it is contained in the pituitary gland, blood. Thyroid gland, adrenal glands. Bromides in small doses (0.1-0.3 adult) are not positively valid nervous system As amplifiers of braking processes in the cerebral cortex. In nature, bromide accumulates in plants such as rye, wheat, barley, potatoes, carrots, cherry, apples. Many bromine is contained in Dutch cheese. Iodine In the human body begins to accumulate in the womb. In the hormone of the thyroid gland of man - thyroxine - contains 60% of the associated iodine. This hormone with blood flow enters the liver, kidneys, dairy glands, gastrointestinal tract. The disadvantage of iodine in the human body causes diseases such as endemic goiter and cretinism, in which growth slows down and mental retardation develops. In combination with other elements, iodine contributes to the growth and respancies of animals, improves their health and fertility. The main suppliers of iodine for a person are cereals, eggplants, beans, white cabbage and colored, potatoes, onions, carrots, cucumbers, pumpkin, salad, sea cabbage, squid.

State Educational Standard

Introduced from the moment of statement in Moscow 2000 Generalcharacteristic Directions of the preparation of a graduate specialist "Security ..., Types of interaction, alloys, use in the technique. Nemetalla, properties, use, the most important compounds - oxides ...

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In nature. 3. The kingdom of mushrooms (3 hours) mushrooms. Generalcharacteristic Mushrooms, their structure and vital activity. Yeast ... recognition and receipt of substances. Topic 2. Nemetalla (27 o'clock) Generalcharacteristicnemmetalov: position in the periodic system D. I. ...

The main educational program of the initial and secondary general education "Secondary School No. 10"

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Specified general Main goals common Education taking into account specifics training subject; 2) generalcharacteristic Educational ... in electrolyte solutions. Variety of substances Generalcharacteristicnemmetalov Based on their position in the periodic ...

The very first scientific classification of chemical elements was dividing them to metals and non-metals. This classification has not lost its significance and now.

Of the 118 currently known chemical elements of the element of the element form these substances with non-metallic properties.

Nonmetals are located in III-VII groups. According to physical properties, VIII group, or a group of noble gases, should also be attributed to nonmetallam. Nemetalla form p.- elements, as well as hydrogen and helium, which are s.- elements. In a long periodic table p.-Elements that form non-metals are eligible and higher than the B-AT conditional boundary.

Group	I.	III	IV	V.	VI	VII	VIII.
1st period	H.						He.
2nd period		B.	C.	N.	O.	F.	Ne
3rd period			SI	P.	S.	Cl.	AR
4th period				As	SE	Br.	Kr.
5th period					TE	I.	Xe.
6th period						AT.	RN.

Nemetalla - These are chemical elements for the atoms of which are characteristic of the ability to take electrons before the external layer is completed due to the existence, as a rule, on the outer electron layer of four or more electrons and the small radius of atoms compared to metals atoms.

2. Features of the structure of nemetal atoms.

In most non-metal atoms from four to eight valence electrons in the outer layer, but at the hydrogen atom, one, at the helium atom - two, and at the boron atom - three valence electrons, a small radius of an atom (orbital radius is less than 0.1 nm). Therefore, Nemmetalov atoms seek to bring the missing to 8e. This property of atoms is characterized by electronegitability. For non-metal atoms, high electronegability values \u200b\u200bare characteristic. It changes from 2 to 4.

In accordance with it, nonmetals form a special range:

Fluorine - The strongest oxidizing agent, its atoms in chemical reactions are not able to give electrons, that is, to show rehabilitation properties.

Atoms, non-metals are dominated by oxidative properties, that is, the ability to attach electrons. This ability characterizes the value of electronegability, which naturally changes in periods and subgroups.

Non-metals may exhibit replacement properties, although in a much weaker extent compared with metals: in periods and subgroups, their restorative ability varies in reverse order Compared to oxidative.

The characteristics of non-metal elements and their compounds are naturally changed in groups and periods.

In periods (with an increase in the sequence number, i.e. left and right):

· Increases the charge of the nucleus,

· The number of external electrons increases,

· The radius of atoms is reduced,

· Increases the strength of the connection of electrons with the kernel (ionization energy),

· Increases electronegability,

· The oxidative properties of simple substances ("non-metalliousness") (except for the elements of the group VIIIA),

· Weakens the rehabilitation properties of simple substances ("Metality") (except the elements of the group VIIIA),

· Weakens the basic nature of hydroxides and appropriate oxides,

· Increases the acidic nature of hydroxides and appropriate oxides,

· Valence in compound with oxygen increases from 3 to 7, the highest valence is equal to the number number.

In groups (with an increase in the sequence number, i.e. from top to bottom):

· Increases the charge of the nucleus,

· Increases atoms (only in the main subgroups),

· The strength of the connection of electrons with the kernel decreases (ionization energy; only in the main subgroups),

· Electricity decreases (only in the main subgroups),

· Weakens the oxidative properties of simple substances ("non-metalliousness"; only in the main subgroups) (except the elements of the group VIIIA),

· The restorative properties of simple substances ("Metality" are strengthened; only in the main subgroups) (except for the elements of the group VIIIA),

· The main character of hydroxides and appropriate oxides (only in the main subgroups),

· Weakens the acid character of hydroxides and appropriate oxides (only in the main subgroups),

· The stability of hydrogen compounds is reduced (their reduction activity increases; only in the main subgroups),

· The valence of elements does not change and equal to the number number.

Type of communication, characteristic of non-metals:

· Ionic (Ksi) ;

· Covalent (non-polar - in simple substances (C1 2)

· Polar - in unmetall connections (SCL 2.).

However, it should be especially highlighted at the dual position of hydrogen in the periodic system: in I and VII groups of the main subgroups. This is not by chance. On the one hand, a hydrogen atom, like atoms alkali metalsHas on the outer (and only one for it) one electron layer (electronic 1s 1 configuration), which is able to give, showing the properties of the reducing agent.

In most of its compounds, hydrogen, as well as alkali metals, shows the degree of oxidation +1, but the return of the electron at the hydrogen atom is harder than that of alkali metal atoms. On the other hand, atom of hydrogen, as well as halogen atoms, to complete the outer electron layer there is a lack of one electron, so hydrogen atom can take one electron, showing the properties of the oxidant and characteristic of halogen degree of oxidation -1 in hydrides - compounds with metals like metal compounds With halogens - halides. But the addition of one electron to the hydrogen atom occurs harder than halogen.

Under normal conditions, hydrogen H 2 - gas. His molecule, like halogens, doubles.

Elements of the VIII of the main subgroup group are inert or noble gases whose atoms have a complete outer electron layer. The electronic configuration of atoms of these elements is such that they cannot be attributed to any metals or non-metallam. They are those objects that in the natural system are clearly separated by elements on metals and non-metals, occupying between them the border position. Inert or noble gases ("nobility" is expressed in inertia) sometimes refer to nonmetallam, but purely formally, according to physical signs. These substances retain a gaseous state up to very low temperatures.

Inertia in chemical relations in these elements is relative. For xenon and crypton, connections with fluorine and oxygen are known. Undoubtedly, in the formation of these compounds, the inert gases acted as reducing agents.

3. The prevalence of non-metal elements.

Oxygen and siliconthey are the most common elements, their share accounts for about 70% of the mass of the earth's crust. The rare elements include iodine, selenium, tellurium and some others, thousands of the percentage of the mass of the earth's crust occur. Many non-metal compounds are a mandatory component of plant and animal organisms. To organogenic elements ("boring" organic substances: proteins, fats, carbohydrates, nucleic acids) include: oxygen O (it accounts for about 60% of human body weight), C, N, N, P and S. in small quantities In the organisms of animals and plants contain F, O, I.

Two non-metal elements make up 76% of the mass of the earth's crust. This is oxygen (49%) and silicon (27%). The atmosphere contains 0.03% of the oxygen mass in earth Kore. Nonmetals are 98.5% of the mass of plants, 97.6% of human body weight. In the air that we breathe are simple and sophisticated substancesAlso formed by non-metals (oxygen O 2, nitrogen, carbon dioxide CO 2, water vapor N 2 O, etc.).

Hydrogen - The main element of the universe. Many space objects (gas clouds, stars, including the sun) more than half consist of hydrogen. On the ground it, including the atmosphere, hydrosphere and a lithosphere, only 0.88%. But this is by mass, and the atomic mass of hydrogen is very small. Therefore, the small content of it is only apparent, and from every 100 atoms on Earth 17 - hydrogen atoms.

4. Non-metals are simple substances. Structure.

In simple substances, non-metal atoms are associated with a covalent non-polar bond; in noble gases chemical ties not. Due to this, a more stable electronic system is formed than in isolated atoms. At the same time, single (for example, in hydrogen molecules H 2, CL 2 halogen molecules, Vg 2), double (for example, in oxygen molecules) are triggers (for example, in nitroles) covalent bonds.

We turn to the consideration of the structure of non-metal molecules. Nonmetals form both monatomic and ductomic molecules.

The monoatomic nonmetallams include inert gases, practically not reacting even with the most active substances. Inert gases are located in the VIII group Periodic system, and the chemical formulas of the corresponding simple substances are as follows: HE, NE, AR, KR, XE and RN.

Some non-metals form diatomic molecules. These are halogens - F 2, CL 2, BR 2, I 2 (elements of the VII group of the periodic system), as well as H 2, N 2, O 2. Ozone, phosphorus, sulfur atoms - from more Atoms (O 3, P 4, S 8), inert gases - from one atom (non, NE, Ar, Kr).

For substances of non-metals, which are in a solid state, make a chemical formula quite difficult. Carbon atoms in graphite are connected to each other in different ways. Select a separate molecule in the above structures is difficult. When writing the chemical formulas such as substances, as in the case of metals, assumes are introduced that such substances consist only of atoms. Chemical formulas, while recorded without indexes - C, Si, S, etc.

The most typical nonmetals have a molecular structure, and less typical - non-elastic. This explains the difference between their properties.

1. Molecular structure. These nonmetals in solid statemolecular crystal lattices. In this case, in each molecule, the atoms are connected quite firmly covalent bond, but the individual molecules with each other in the crystals of the substance are very weakly connected. Therefore, under normal conditions, most of these substances are gases or solids low melting And only the only bromine (VG 2) is a liquid. All these substances of the molecular structure, so volatile. In solid state, they are low saline due to the weak intermolecular interaction, holding their molecules in the crystal, and are capable of sublimation.

Molecular non-metals: H 2, N 2, P 4 (white phosphorus), AS 4, O 2, O 3, S 8, F 2, CL 2, I 2. The noble gases (HE, NE, AR, KR, KX, RN) can also be attributed to them, the atoms of which are like "single-matlas".

2. Atomic structure. These nonmetallesatomic crystal lattices , therefore, they have a large hardness and very high melting temperatures. These substances are formed by long chains of atoms. Due to the high strength of covalent bonds, they tend to have high hardness, and any changes associated with the destruction of covalent bonds in their crystals (melting, evaporation) are made with high energy consideration. Many such substances have high temperatures Melting and boiling, and their volatility is quite small.

Nemolecular non-metals: B (several allotropic modifications), C (graphite), C (diamond), Si, Ge, P (red), P (black), as, SE, TE. All of them solids, silicon, germanium, selenium and some others have semiconductor properties.

The cause of a wide variety of physical properties of non-metals lies in a different structure of crystalline decisions of these substances.

Part of non-metals has atomic crystal lattice. Crystals of such substances consist of atoms connected by durable covalent bonds. Such nonmetals are in solid aggregate state And are non-volatile. Examples of such substances are diamond, graphite, red phosphorus and silicon.

Models of crystal lattices diamond (left) and graphite. The crystals of these allotropic modifications consist of carbon atoms connected by covalent bonds. Graphite crystals, in contrast to diamond crystals, are composed of separate layers, which are located with each other, just like sheets of paper in the book.

Many non-metal elements form several simple substances - allotropic modifications.

Allotropy is the ability of atoms of one chemical element to form several simple substances. And these simple substances - allotropic modifications or modifications.

Allotropy can be associated with different composition of molecules - different number of atoms in the molecule (O 2 and O 3), and with a different structure of crystals. Allotropic modifications formed by the same chemical element, significantly different among themselves in both the structure and properties.