1. The position of metals in the table of elements

Metals are located mainly in the left and lower part of the PSCE. These include:

2. The structure of metal atoms

Metal atoms usually have 1-3 electrons at the outer energy level. Their atoms have a large radius and easily donate valence electrons, i.e. exhibit restorative properties.

3. Physical properties of metals

Change in the electrical conductivity of a metal during its heating and cooling

metal connection - this is the bond that free electrons carry out between cations in a metal crystal lattice.

4. Obtaining metals

1. Recovery of metals from oxides with coal or carbon monoxide

Me x O y + C \u003d CO 2 + Me or Me x O y + CO \u003d CO 2 + Me

2. Sulfide roasting followed by reduction

1 stage - Me x S y + O 2 \u003d Me x O y + SO 2

Stage 2 -Me x O y + C \u003d CO 2 + Me or Me x O y + CO \u003d CO 2 + Me

3 Aluminothermy (recovery with a more active metal)

Me x O y + Al \u003d Al 2 O 3 + Me

4. Hydrothermy - to obtain high purity metals

Me x O y + H 2 = H 2 O + Me

5. Recovery of metals by electric current (electrolysis)

1) Alkali and alkaline earth metals obtained in industry by electrolysis salt melts (chlorides):

2NaCl - melt, electr. current. → 2 Na + Cl 2

CaCl 2 - melt, electr. current.→ Ca + Cl2

hydroxide melts:

4NaOH - melt, electr. current.→ 4 Na + O 2 + 2 H 2 O

2) Aluminum industrially produced by electrolysis aluminum oxide melt I in cryolite Na 3 AlF 6 (from bauxite):

2Al 2 O 3 - melt in cryolite, electr. current.→ 4 Al + 3 O 2

3) Electrolysis aqueous solutions salts use to obtain metals of medium activity and inactive:

2CuSO 4 + 2H 2 O - solution, electr. current.→ 2 Cu + O 2 + 2 H 2 SO 4

5. Finding metals in nature

The most common in earth's crust metal is aluminium. Metals are found both in compounds and in free form.

1. Active - in the form of salts (sulfates, nitrates, chlorides, carbonates)

2. Medium activity – in the form of oxides, sulfides ( Fe 3 O 4 , FeS 2 )

3. Noble - in free form ( Au, Pt, Ag)

CHEMICAL PROPERTIES OF METALS

General Chemical properties metals are presented in the table:

TASKS FOR REINFORCEMENT

No. 1. Finish Equations practicable reactions name the reaction products

Li + H 2 O \u003d

Cu + H 2 O \u003d

Al + H 2 O \u003d

Ba + H 2 O =

Mg + H 2 O \u003d

Ca+HCl=

Na + H 2 SO 4 (K) \u003d

Al + H 2 S \u003d

Ca + H 3 PO 4 \u003d

HCl + Zn =

H 2 SO 4 (to) + Cu \u003d

H 2 S + Mg =

HCl + Cu =

HNO 3 (K) + C u =

H 2 S + Pt =

H 3 PO 4 + Fe =

HNO 3 (p)+ Na=

Fe + Pb(NO 3) 2 =

No. 2. Finish UHR, arrange the coefficients using the electronic balance method, indicate the oxidizing agent (reducing agent):

Al + O 2 \u003d

Li + H 2 O =

Na + HNO 3 (k) =

Mg + Pb (NO 3) 2 \u003d

Ni + HCl =

Ag + H 2 SO 4 (k) \u003d

No. 3. Insert missing characters instead of dots (<, >or =)

Core charge	Li…Rb	Na…Al	Ca…K
Number of energy levels	Li…Rb	Na…Al	Ca…K
Number of outer electrons	Li…Rb	Na…Al	Ca…K
Atom radius	Li…Rb	Na…Al	Ca…K
Restorative properties	Li…Rb	Na…Al	Ca…K

No. 4. Finish UHR, arrange the coefficients using the electronic balance method, indicate the oxidizing agent (reducing agent):

K + O 2 \u003d

Mg + H 2 O \u003d

Pb + HNO 3 (p) =

Fe + CuCl 2 \u003d

Zn + H 2 SO 4 (p) \u003d

Zn + H 2 SO 4 (k) \u003d

No. 5. Solve test tasks

1.Select a group of elements that contains only metals: A) Al, As, P; B) Mg, Ca, Si; B) K, Ca, Pb 2. Select a group in which there are only simple substances - non-metals: A) K 2 O, SO 2, SiO 2; B) H 2 , Cl 2 , I 2 ; B )Ca, Ba, HCl; 3. Indicate what is common in the structure of K and Li atoms: A) 2 electrons on the last electron layer; B) 1 electron on the last electron layer; C) the same number of electronic layers. 4. Metal calcium exhibits properties: A) an oxidizing agent B) reducing agent; C) an oxidizing or reducing agent, depending on the conditions. 5. The metallic properties of sodium are weaker than those of - A) magnesium; B) potassium; C) lithium. 6. Inactive metals include: A) aluminum, copper, zinc; B) mercury, silver, copper; C) calcium, beryllium, silver. 7. What is the physical property is not common to all metals: A) electrical conductivity, B) thermal conductivity, B) solid state of aggregation under normal conditions, D) metallic luster

Part B. The answer to the tasks of this part is a set of letters that should be written down Set a match. With the increase serial number element in the main subgroup of group II of the Periodic system, the properties of the elements and the substances they form change as follows:

1. What features of the structure of metal atoms determine their reducing properties?

The reducing properties of metals are determined by the ability to donate electrons from the outer layer. The easier an atom donates electrons to the outer layer, the stronger the reducing agent it is.

2. Name the chemical element that forms a simple substance - the most active metal. Justify your choice.

The most active metal is francium (Fr).

Francium most easily donates an electron to the outer layer. It has the largest atomic radius, so the energy of interaction of the atomic nucleus with the outer electron shell small.

3. How does the statement that metals exhibit only reducing properties and, therefore, oxidize at the same time, agree with the process that can be reflected using the equation: Name this process. In what forms of existence of the chemical element does copper appear? For what form of existence chemical elements Is the above statement true?

Metals exhibit reducing properties in the zero oxidation state, i.e. the metal itself can only be a reducing agent. The above process is an example of the oxidation of Cu2+ to Cu0. In this example, copper acts as a cation.

Introduction

Metals are simple substances that under normal conditions have characteristic properties: high electrical and thermal conductivity, the ability to reflect light well (which causes their brilliance and opacity), the ability to take the desired shape under the influence of external forces (plasticity). There is another definition of metals - these are chemical elements characterized by the ability to donate external (valence) electrons.

Of all the known chemical elements, about 90 are metals. Majority inorganic compounds are compounds of metals.

There are several types of classification of metals. The most clear is the classification of metals in accordance with their position in periodic system chemical elements - chemical classification.

If, in the "long" version of the periodic table, a straight line is drawn through the elements boron and astatine, then metals will be located to the left of this line, and non-metals to the right of it.

From the point of view of the structure of the atom, metals are divided into intransitive and transitional. Non-transition metals are located in the main subgroups of the periodic system and are characterized by the fact that in their atoms there is a sequential filling of the electronic levels s and p. Intransition metals include 22 elements of the main subgroups a: Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Al, Ga, In, Tl, Ge, Sn, Pb, Sb, Bi, Po.

Transition metals are located in side subgroups and are characterized by the filling of d - or f -electronic levels. The d-elements include 37 metals of secondary subgroups b: Cu, Ag, Au, Zn, Cd, Hg, Sc, Y, La, Ac, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo , W , Sg , Mn , Tc , Re , Bh , Fe , Co , Ni , Ru , Rh , Pd , Os , Ir , Pt , Hs , Mt .

The f-element includes 14 lanthanides (Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, D y, Ho, Er, Tm, Ub, Lu) and 14 actinides (Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lr).

Among the transition metals, rare earth metals (Sc, Y, La and lanthanides), platinum metals (Ru, Rh, Pd, Os, Ir, Pt), transuranium metals (N p and elements with a higher atomic mass) are also distinguished.

In addition to chemical, there is also, although not generally accepted, but long established technical classification of metals. It is not as logical as chemical one - it is based on one or another practically important feature of the metal. Iron and alloys based on it are classified as ferrous metals, all other metals are non-ferrous. There are light (Li, Be, Mg, Ti, etc.) and heavy metals (Mn, F e, Co, Ni, Cu, Zn, Cd, Hg, Sn, Pb, etc.), as well as groups of refractory (Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, R e), precious (Ag, Au, platinum metals) and radioactive (U, Th, N p, Pu, etc.) metals. In geochemistry, scattered (Ga, Ge, Hf, Re, etc.) and rare (Zr, Hf, Nb, Ta, Mo, W, Re, etc.) metals are also distinguished. As you can see, there are no clear boundaries between groups.

History reference

Despite the fact that the life of human society without metals is impossible, no one knows exactly when and how a person first began to use them. The most ancient writings that have come down to us tell about primitive workshops in which metal was smelted and products were made from it. This means that man mastered metals earlier than writing. Excavating ancient settlements, archaeologists find tools of labor and hunting that people used in those distant times - knives, axes, arrowheads, needles, fish hooks and much more. How ancient settlement, the rougher and more primitive were the products of human hands. The most ancient metal products were found during excavations of settlements that existed about 8 thousand years ago. These were mainly jewelry made of gold and silver and arrowheads and spears made of copper.

The Greek word "metallon" originally meant mines, mines, hence the term "metal" came from. In ancient times, it was believed that there were only 7 metals: gold, silver, copper, tin, lead, iron and mercury. This number correlated with the number of planets known then - the Sun (gold), the Moon (silver), Venus (copper), Jupiter (tin), Saturn (lead), Mars (iron), Mercury (mercury) (see figure) . According to alchemical ideas, metals were born in the bowels of the earth under the influence of the rays of the planets and gradually improved, turning into gold.

Man first mastered native metals - gold, silver, mercury. The first artificially obtained metal was copper, then it was possible to master the production of an alloy of copper by nightingale - bronze, and only later - iron. In 1556, a book by the German metallurgist G. Agricola "On Mining and Metallurgy" was published in Germany - the first detailed guide to obtaining metals that has come down to us. True, at that time lead, tin and bismuth were still considered varieties of the same metal. In 1789, the French chemist A. Lavoisier, in his manual on chemistry, gave a list of simple substances, which included all the then known metals - antimony, silver, bismuth, cobalt, tin, iron, manganese, nickel, gold, pla - mud, lead, tungsten and zinc. With the development of chemical research methods, the number of known metals began to increase rapidly. In the 18th century 14 metals were discovered, in the 19th century. - 38, in the 20th century. - 25 metals. In the first half of the 19th century satellites of platinum were discovered, alkali and alkaline earth metals were obtained by electrolysis. In the middle of the century, cesium, rubidium, thallium and indium were discovered by spectral analysis. The existence of metals predicted by D. I. Mendeleev on the basis of his periodic law (these are gallium, scandium and germanium) was brilliantly confirmed. The discovery of radioactivity at the end of the 19th century. led to the search for radioactive metals. Finally, by the method of nuclear transformations in the middle of the 20th century. radioactive metals that do not exist in nature, in particular transuranium elements, were obtained.

Physical and chemical properties of metals.

All metals are solids (except mercury, which is liquid under normal conditions), they differ from non-metals special kind bonds (metal bond). Valence electrons are loosely bound to a particular atom, and inside every metal there is a so-called electron gas. Most metals have a crystalline structure, and a metal can be thought of as a "rigid" crystal lattice of positive ions (cations). These electrons can more or less move around the metal. They compensate for the repulsive forces between cations and thus bind them into a compact body.

All metals have high electrical conductivity (that is, they are conductors, unlike non-metals-dielectrics), especially copper, silver, gold, mercury and aluminum; the heat conductivity of metals is also high. A distinctive property of many metals is their ductility (ductility), as a result of which they can be rolled into thin sheets (foil) and drawn into wire (tin, aluminum, etc.), however, there are also quite brittle metals (zinc, antimony , bismuth).

In industry, not pure metals are often used, but their mixtures, called alloys. In an alloy, the properties of one component usually successfully complement the properties of another. So, copper has a low hardness and is of little use for the manufacture of machine parts, while copper-zinc alloys, called brass, are already quite hard and are widely used in mechanical engineering. Aluminum has good ductility and sufficient lightness (low density), but is too soft. On its basis, an alloy of ayuralumin (duralumin) is prepared, containing copper, magnesium and manganese. Duralumin, without losing the properties of its aluminum, acquires high hardness and is therefore used in aviation technology. Alloys of iron with carbon (and additions of other metals) are well-known cast iron and steel.

Metals vary greatly in density: for lithium it is almost half that of water (0.53 g / cm 3), and for osmium it is more than 20 times higher (22.61 g / cm 3). Metals also differ in hardness. The softest - alkali metals, they are easily cut with a knife; the hardest metal - chromium - cuts glass. The difference in melting points of metals is great: mercury is a liquid under normal conditions, cesium and gallium melt at the temperature of the human body, and the most refractory metal, tungsten, has a melting point of 3380 ° C. Metals whose melting point is above 1000 ° C are classified as refractory metals, lower - as fusible. At high temperatures, metals are capable of emitting electrons, which is used in electronics and thermoelectric generators for the direct conversion of thermal energy into electrical energy. Iron, cobalt, nickel and gadolinium, after being placed in a magnetic field, are able to permanently maintain a state of magnetization.

Metals also have some chemical properties. Metal atoms give up valence electrons relatively easily and pass into positively charged ions. Therefore, metals are reducing agents. This, in fact, is their main and most common chemical property.

Obviously, metals as reducing agents will react with various oxidizing agents, among which there may be simple substances, acids, salts of less active metals, and some other compounds. Compounds of metals with halogens are called halides, with sulfur - sulfides, with nitrogen - nitrides, with phosphorus - phosphides, with carbon - carbides, with silicon - silicides, with boron - borides, with hydrogen - hydrides, etc. Many of these compounds have found important applications in the new technology. For example, metal borides are used in radio electronics, as well as in nuclear technology as materials for regulating neutron radiation and protecting against it.

Under the action of concentrated oxidizing acids, a stable oxide film is also formed on some metals. This phenomenon is called passivation. So, in concentrated sulfuric acid, metals such as Be, Bi, Co, F e, Mg, and Nb are passivated (and do not react with it), and in concentrated nitric acid - metals Al, Be, Bi , Co, Cr, F e, Nb, Ni, Pb, Th and U.

The more to the left the metal is located in this row, the greater the reducing properties it has, i.e., it is more easily oxidized and goes into solution in the form of a cation, but it is more difficult to recover from the cation to the free state.

One non-metal, hydrogen, is placed in a series of voltages, since this allows you to determine whether this metal will react with acids - non-oxidizing agents in an aqueous solution (more precisely, it will be oxidized by hydrogen cations H +). For example, zinc reacts with hydrochloric acid, since in the series of voltages it is to the left (before) hydrogen. On the contrary, silver is not transferred into solution by hydrochloric acid, since it is in the series of voltages to the right (after) hydrogen. Metals behave similarly in dilute sulfuric acid. Metals that are in the series of voltages after hydrogen are called noble (Ag, Pt, Au, etc.)

periodic system D.I. Mendeleev subdivided into ... period (excluding the first) begins alkaline metal and ends with a noble gas. Elements 2...

periodic system elements Mendeleev

Abstract >> Chemistry

II. Periodic law and periodic system chemical elements Opening D.I. Mendeleev Periodic Law Structure Periodic systems a) ... - non-metal, and bismuth - metal). IN Periodic system typical metals located in group IA (Li...

Periodic D.I. law Mendeleev (2)

Biography >> Biology

connections. He determined that metals correspond to basic oxides and bases, ... and hydroxides in some metals brought confusion. The classification was ... atoms of chemical elements in Periodic system DI. Mendeleev change monotonically, so...

periodic system and its importance in the development of chemistry D.I. Mendeleev

Abstract >> Chemistry

Periods refer to s-elements (alkaline and alkaline earth metals), constituting Ia- and IIa-subgroups (highlighted ... the scientific basis for teaching chemistry. Conclusion periodic system D.I. Mendeleev became a milestone in the development of atomic...

B about Most of the known chemical elements form simple substances, metals.

Metals include all elements of secondary (B) subgroups, as well as elements of the main subgroups located below the diagonal "beryllium - astatine" (Fig. 1). In addition, the chemical elements metals form groups of lanthanides and actinides.

Rice. 1. The location of metals among the elements of subgroups A (highlighted in blue)

Compared to non-metal atoms, metal atoms have b about Larger sizes and fewer outer electrons, usually 1-2. Consequently, the outer electrons of metal atoms are weakly bound to the nucleus; metals easily give them away, exhibiting reducing properties in chemical reactions.

Consider the patterns of change in some properties of metals in groups and periods.

In periodsfrom As the nuclear charge increases, the atomic radius decreases. The nuclei of atoms attract outer electrons more and more, therefore, the electronegativity of atoms increases, the metallic properties decrease. Rice. 2.

Rice. 2. Change in metallic properties in periods

In the main subgroups from top to bottom in metal atoms, the number of electron layers increases, therefore, the radius of atoms increases. Then the outer electrons will be weaker attracted to the nucleus, so there is a decrease in the electronegativity of atoms and an increase in metallic properties. Rice. 3.

Rice. 3. Change in metallic properties in subgroups

These regularities are also characteristic of the elements of secondary subgroups, with rare exceptions.

Atoms of metal elements tend to donate electrons. In chemical reactions, metals act only as reducing agents, they donate electrons and increase their oxidation state.

The atoms that make up simple substances, non-metals, as well as the atoms that make up the composition, can accept electrons from metal atoms. complex substances, which are able to lower their oxidation state. For example:

2Na 0 + S 0 = Na +1 2 S -2

Zn 0 + 2H +1 Cl \u003d Zn +2 Cl 2 + H 0 2

Not all metals have the same chemical activity. Some metals under normal conditions practically do not enter into chemical reactions They are called noble metals. The noble metals include: gold, silver, platinum, osmium, iridium, palladium, ruthenium, rhodium.

Noble metals are very rare in nature and are almost always found in native state(Fig. 4). Despite their high resistance to corrosion-oxidation, these metals still form oxides and other chemical compounds, for example, silver chloride and nitrate salts are known to everyone.

Rice. 4. Nugget of gold

Summing up the lesson

In this lesson, you examined the position of the chemical elements of metals in the Periodic Table, as well as the structural features of the atoms of these elements, which determine the properties of simple and complex substances. You have learned why there are much more chemical elements of metals than non-metals.

Bibliography

1. Orzhekovsky P.A. Chemistry: 9th grade: textbook for general education. inst. / P.A. Orzhekovsky, L.M. Meshcheryakova, M.M. Shalashova. - M.: Astrel, 2013. (§28)
2. Rudzitis G.E. Chemistry: inorgan. chemistry. Organ. chemistry: textbook. for 9 cells. / G.E. Rudzitis, F.G. Feldman. - M.: Enlightenment, JSC "Moscow textbooks", 2009. (§34)
3. Khomchenko I.D. Collection of tasks and exercises in chemistry for high school. - M.: RIA "New Wave": Publisher Umerenkov, 2008. (p. 86-87)
4. Encyclopedia for children. Volume 17. Chemistry / Chapter. ed. V.A. Volodin, leading. scientific ed. I. Leenson. - M.: Avanta +, 2003.

1. A single collection of digital educational resources (video experiences on the topic) ().
2. Electronic version of the journal "Chemistry and Life" ().

Homework

1. from. 195-196 No. 7, A1-A4 from the textbook by P.A. Orzhekovsky "Chemistry: 9th grade" / P.A. Orzhekovsky, L.M. Meshcheryakova, M.M. Shalashova. - M.: Astrel, 2013.
2. What properties (oxidizing or reducing) can an Fe 3+ ion have? Illustrate your answer with reaction equations.
3. Compare the atomic radius, electronegativity and reducing properties of sodium and magnesium.

The position of metals in the periodic system

If we draw a diagonal from boron to astatine in the Mendeleev table, then in the main subgroups under the diagonal there will be metal atoms, and in the secondary subgroups all elements are metals. Elements located near the diagonal have dual properties: in some of their compounds they behave like metals; in some - as non-metals.

The structure of metal atoms

In periods and main subgroups, there are regularities in the change in metallic properties.

Atoms of many metals have 1, 2, or 3 valence electrons, for example:

Na(+11): 1S2 2S22p6 3S1

Ca(+20): 1S2 2S22p6 3S23p63d0 4S2

Alkali metals (group 1, main subgroup): ... nS1.

Alkaline earth (group 2, main subgroup): ... nS2.

The properties of metal atoms are in a periodic dependence on their location in the table of D. I. Mendeleev.

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a - copper; b) magnesium; c) α-modification of iron

Metal atoms tend to donate their outer electrons. In a piece of metal, ingot or metal product, metal atoms donate external electrons and send them to this piece, ingot or product, turning into ions. The “torn off” electrons move from one ion to another, temporarily reconnect with them into atoms, break off again, and this process occurs continuously. Metals have a crystal lattice, in the nodes of which there are atoms or ions (+); between them are free electrons (electron gas). The connection scheme in metal can be displayed as follows:

М0 ↔ nē + Мn+,

atom - ion

where n is the number of external electrons participating in the bond (y Na - 1, y Sa - 2 ē, y Al - 3 ē).

This type of bond is observed in metals - simple substances-metals and in alloys.

A metallic bond is a bond between positively charged metal ions and free electrons in crystal lattice metals.

The metallic bond has some similarities with the covalent, but also some difference, since the metallic bond is based on the socialization of electrons (similarity), all atoms take part in the socialization of these electrons (difference). That is why crystals with a metallic bond are plastic, electrically conductive and have a metallic sheen. However, in the vapor state, metal atoms are bound together covalent bond, metal pairs consist of individual molecules (monatomic and diatomic).

General characteristics of metals

The ability of atoms to donate electrons (to be oxidized)	← Increasing
Interaction with atmospheric oxygen	Oxidizes quickly at normal temperatures	Slowly oxidized at normal temperature or when heated	Do not oxidize
Interaction with water	At ordinary temperature, H2 is released and hydroxide is formed	When heated, H2 is released	H2 is not displaced from water
Interaction with acids	Displace H2 from dilute acids	Does not displace H2 from dilute acids
React with conc. and razb. HNO3 and conc. H2SO4 when heated	Do not react with acids
Being in nature	Only in connections	In compounds and in free form	Mostly free
How to get	Melt electrolysis	Reduction with coal, carbon monoxide(2), aluminothermy, or electrolysis of aqueous salt solutions
The ability of ions to gain electrons (recover)	Li K Ca Na Mg Al Mn Zn Cr Fe Ni Sn Pb (H) Cu Hg Ag Pt Au
Increasing →

Electrochemical series of voltages of metals. Physical and chemical properties of metals

General physical properties metals

The general physical properties of metals are determined by the metallic bond and the metallic crystal lattice.

Malleability, plasticity

Mechanical action on a metal crystal causes a displacement of the layers of atoms. Since the electrons in the metal move throughout the crystal, there is no breaking of bonds. Plasticity decreases in the series Au, Ag, Cu, Sn, Pb, Zn, Fe. Gold, for example, can be rolled into sheets with a thickness of no more than 0.001 mm, which are used for gilding various objects. Aluminium foil tea appeared relatively recently and earlier, chocolate was forged in tin foil, which was called staniol. However, Mn and Bi do not have plasticity: they are brittle metals.

metallic luster

Metallic luster, which all metals lose in powder, except Al And mg. The brightest metals are hg(the famous "Venetian mirrors" were made from it in the Middle Ages), Ag(modern mirrors are now made from it using the “silver mirror” reaction). Ferrous and non-ferrous metals are (conditionally) distinguished by color. Among the latter, we single out precious ones - Au, Ag, Pt. Gold is the metal of jewelers. It was on its basis that wonderful Faberge Easter eggs were made.

ringing

Metals ring, and this property is used to make bells (remember the Tsar Bell in the Moscow Kremlin). The most sonorous metals are Au, Ag, Cu. Copper rings with a thick, buzzing ringing - crimson ringing. This figurative expression is not in honor of the raspberry, but in honor of the Dutch city of Malina, where the first church bells. In Russia, then Russian masters began to cast bells even best quality, and residents of cities and towns donated gold and silver jewelry so that the bell cast for temples would sound better. In some Russian pawnshops, the authenticity of gold rings accepted for commission was determined by the ringing of a gold wedding ring suspended from a woman's hair (a very long and clear high sound is heard).

Under normal conditions, all metals, except mercury Hg, are solids. The hardest of metals is chromium Cr: it scratches glass. The softest are alkali metals, they are cut with a knife. Alkali metals are stored with great care - Na - in kerosene, and Li - in vaseline because of its lightness, kerosene - in a glass jar, a jar - in asbestos chips, asbestos - in a tin jar.

Electrical conductivity

The good electrical conductivity of metals is explained by the presence of free electrons in them, which, under the influence of even a small potential difference, acquire a directed movement from the negative pole to the positive. As the temperature rises, vibrations of atoms (ions) increase, which makes it difficult for the directed movement of electrons and thereby leads to a decrease in electrical conductivity. At low temperatures, the oscillatory motion, on the contrary, greatly decreases and the electrical conductivity increases sharply. Near absolute zero, metals exhibit superconductivity. Ag, Cu, Au, Al, Fe have the highest electrical conductivity; the worst conductors are Hg, Pb, W.

Thermal conductivity

Under normal conditions, the thermal conductivity of metals changes mainly in the same sequence as their electrical conductivity. Thermal conductivity is due to the high mobility of free electrons and oscillating motion atoms, due to which there is a rapid equalization of temperature in the mass of the metal. The highest thermal conductivity is for silver and copper, the lowest for bismuth and mercury.

Density

The density of metals is different. It is less the less atomic mass element-metal and the greater the radius of its atom. The lightest metal is lithium (density 0.53 g/cm3), the heaviest is osmium (density 22.6 g/cm3). Metals with a density less than 5 g/cm3 are called light, the rest are called heavy.

The melting and boiling points of metals are varied. The most fusible metal is mercury (tboil = -38.9°C), cesium and gallium melt at 29 and 29.8°C, respectively. Tungsten is the most refractory metal (tboil = 3390°C).

The concept of allotropy of metals on the example of tin

Some metals have allotropic modifications.

For example, tin is distinguished by:

α-tin, or gray tin ("tin plague" - the transformation of ordinary β-tin into α-tin during low temperatures caused the death of R. Scott's expedition to South Pole, which has lost all the fuel, since it was stored in tanks sealed with tin), is stable at t<14°С, серый порошок.

β-tin, or white tin (t = 14 - 161 ° C) is a very soft metal, but harder than lead, can be cast and soldered. It is used in alloys, for example, for the manufacture of tinplate (tinned iron).

Electrochemical series of voltages of metals and its two rules

The arrangement of atoms in a row according to their reactivity can be represented as follows:

Li, K, Ca, Na, Mg, Al, Mn, Zn, Fe, Ni, Sn, Pb,H2 , Сu, Hg, Ag, Pt, Au.

The position of an element in the electrochemical series shows how easily it forms ions in an aqueous solution, that is, its reactivity. The reactivity of elements depends on the ability to accept or donate electrons involved in bond formation.

1st voltage series rule

If the metal is in this row before hydrogen, it is able to displace it from acid solutions, if after hydrogen, then no.

For example, Zn, Mg, Al gave a substitution reaction with acids (they are in a series of voltages up to H), but Cu no (she after H).

2nd stress series rule

If a metal is in a series of voltages up to the metal of the salt, then it is able to displace this metal from the solution of its salt.

For example, CuSO4 + Fe = FeSO4 + Cu.

In such cases, the position of the metal before or after hydrogen may not matter, it is important that the reacting metal precede the salt-forming metal:

Cu + 2AgNO3 = 2Ag + Cu(NO3)2.

General chemical properties of metals

In chemical reactions, metals are reducing agents (donate electrons).

Interaction simple substances .

1. Metals form salts with halogens - halides:

Mg + Cl2 = MgCl2;

Zn + Br2 = ZnBr2.

2. Metals form oxides with oxygen:

4Na + O2 = 2 Na2O;

2Cu + O2 = 2CuO.

3. Metals form salts with sulfur - sulfides:

4. With hydrogen, the most active metals form hydrides, for example:

Ca + H2 = CaH2.

5. with carbon, many metals form carbides:

Ca + 2C = CaC2.

Interaction with complex substances

1. Metals at the beginning of a series of voltages (from lithium to sodium), under normal conditions, displace hydrogen from water and form alkalis, for example:

2Na + 2H2O = 2NaOH + H2.

2. Metals located in a series of voltages up to hydrogen interact with dilute acids (HCl, H2SO4, etc.), as a result of which salts are formed and hydrogen is released, for example:

2Al + 6НCl = 2AlCl3 + 3H2.

3. Metals interact with solutions of salts of less active metals, as a result of which a salt of a more active metal is formed, and a less active metal is released in free form, for example:

CuSO4 + Fe = FeSO4 + Cu.

Metals in nature.

Finding metals in nature.

Most metals occur in nature in the form of various compounds: active metals are found only in the form of compounds; low-active metals - in the form of compounds and in free form; noble metals (Ag, Pt, Au...) in free form.

Native metals are usually found in small amounts in the form of grains or inclusions in rocks. Occasionally there are quite large pieces of metals - nuggets. Many metals in nature exist in a bound state in the form of natural chemical compounds - minerals. Very often these are oxides, for example, iron minerals: red iron ore Fe2O3, brown iron ore 2Fe2O3 ∙ 3H2O, magnetic iron ore Fe3O4.

Minerals are part of rocks and ores. Ores called mineral-containing natural formations in which metals are in quantities suitable technologically and economically for the production of metals in industry.

According to the chemical composition of the mineral included in the ore, oxide, sulfide and other ores are distinguished.

Usually, before obtaining metals from ore, it is pre-enriched - empty rock, impurities are separated, as a result, a concentrate is formed, which serves as a raw material for metallurgical production.

Methods for obtaining metals.

Obtaining metals from their compounds is the task of metallurgy. Any metallurgical process is a process of reduction of metal ions with the help of various reducing agents, as a result of which metals are obtained in a free form. Depending on the method of carrying out the metallurgical process, pyrometallurgy, hydrometallurgy and electrometallurgy are distinguished.

Pyrometallurgy- this is the production of metals from their compounds at high temperatures using various reducing agents: carbon, carbon monoxide (II), hydrogen, metals (aluminum, magnesium), etc.

Metal Recovery Examples

ZnO + C → Zn + CO2;

carbon monoxide:

Fe2O3 + 3CO → 2Fe + 3CO2;

hydrogen:

WO3 + 3H2 → W + 3H2O;

CoO + H2 → Co + H2O;

aluminum (aluminothermy):

4Al + 3MnO2 → 2Al2O3 + 3Mn;

Cr2O3 + 2Al = 2Al2O3 + 2Cr;

Magnesium:

TiCl4 + 2Mg = Ti + 2MgCl2.

Hydrometallurgy- this is the production of metals, which consists of two processes: 1) a natural metal compound is dissolved in an acid, resulting in a solution of a metal salt; 2) from the resulting solution, this metal is displaced by a more active metal. For example:

1. 2CuS + 3O2 = 2CuO + 2SO2.

CuO + H2SO4 = CuSO4 + H2O.

2. CuSO4 + Fe = FeSO4 + Cu.

Electrometallurgy is the production of metals by electrolysis of solutions or melts of their compounds. The role of the reducing agent in the electrolysis process is played by an electric current.

General characteristics of metals of the IA group.

The metals of the main subgroup of the first group (IA-groups) include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr). These metals are called alkali metals, since they and their oxides form alkalis when interacting with water.

Alkali metals are s-elements. Metal atoms have one s-electron (ns1) on the outer electron layer.

Potassium, sodium - simple substances

Alkali metals in ampoules:
a - cesium; b - rubidium; c - potassium; g - sodium

Basic information about the elements of group IA

	Li lithium	Na sodium	K potassium	Rb rubidium	Cs cesium	Fr French
atomic number
Oxidation state
Basic natural compounds	Li2O Al2O3 4SiO2 (spodumene); LiAl(PO4)F, LiAl(PO4)OH (amblygonite)	NaCl (table salt); Na2SO4 10H2O (Glauber's salt, Mirabilite); KCl NaCl (sylvinite)	KCl (sylvin), KCl NaCl (sylvinite); K (potassium feldspar, orthoeye); KCl MgCl2 6H2O (carnallite) - found in plants	As an isoamorphous impurity in potassium minerals - sylvinite and carnallite	4Cs2O 4Al2O3 18 SiO2 2H2O (semi-cyte); satellite of potassium minerals	Actinium α-decay product

Physical Properties

Potassium and sodium are soft silvery metals (cut with a knife); ρ(K) = 860 kg/m3, Tm(K) = 63.7°C, ρ(Na) = 970 kg/m3, Tm(Na) = 97.8°C. They have high thermal and electrical conductivity, color the flame in characteristic colors: K - in a pale purple color, Na - in yellow.

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Interaction with complex substances:

1. 2Na + 2H2O → 2NaOH + H2.

2. 2Na + Na2O2 → 2Na2O.

3. 2Na + 2НCl → 2NaCl + Н2.

Pulp and paper industry" href="/text/category/tcellyulozno_bumazhnaya_promishlennostmz/" rel="bookmark"> paper production, artificial fabrics, soap, for cleaning oil pipelines, in the production of artificial fiber, in alkaline batteries.

Finding metal compoundsIAgroups in nature.

salt ― NaCl- sodium chloride, NaNO3- sodium nitrate (Chilean saltpeter), Na2CO3- sodium carbonate (soda), NaHCO3- sodium bicarbonate (baking soda), Na2SO4- sodium sulfate, Na2SO4 10Н2О- Glauber's salt KCl- potassium chloride, KNO3- potassium nitrate (potassium nitrate), K2SO4- potassium sulfate, K2CO3- potassium carbonate (potash) - crystalline ionic substances, almost all soluble in water. Sodium and potassium salts exhibit the properties of medium salts:

2NaCl (solid) + H2SO4 (conc.) → Na2SO4 + 2HCl;

KCl + AgNo3 → KNO3 + AgCl ↓;

Na2CO3 + 2HCl → NaCl + CO2 + H2O;

K2CO3 + H2O ↔ KHCO3 + KOH;

CO32- + H2O ↔ HCO3- + OH - (alkaline environment, pH< 7).

salt crystals

salt mine

Na2CO3 serves for the production of paper, soap, glass;

NaHCO3― in medicine, cookery, in production of mineral waters, in fire extinguishers;

K2CO3― for receiving liquid soap and glass;

Potash - potassium carbonate

NaNO3, KNO3, KCl, K2SO4- the most important potash fertilizers.

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Sea salt contains 90-95% NaCl (sodium chloride) and up to 5% other minerals: magnesium salts, calcium salts, potassium salts, manganese salts, phosphorus salts, iodine salts, etc. Together, over 40 useful elements of the periodic table - all this exists in sea water.

The Dead Sea

There is something extraordinary, almost fantastic in it. In the eastern lands, even the tiniest stream of moisture is a source of life, gardens bloom there, cereals ripen. But this water kills all life.

Many peoples have visited these shores: Arabs, Jews, Greeks, Romans; each of them called this huge lake in their own language, but the meaning of the name was the same: dead, dead, lifeless.

We stood on a deserted shore, the dull look of which evoked sadness: a dead land - no grass, no birds. On the other side of the lake reddish mountains rose steeply from the green water. Bare, wrinkled slopes. It seemed that some kind of force tore off their natural cover, and the muscles of the earth were exposed.

We decided to take a dip, but the water turned out to be cold, we only washed ourselves with thick water flowing like a steep brine. A few minutes later, the face and hands were covered with a white coating of salt, and an unbearably bitter taste remained on the lips, from which it was impossible to get rid of for a long time. It is impossible to drown in this sea: thick water itself keeps a person on the surface.

Sometimes fish swim from the Jordan to the Dead Sea. She dies in a minute. We found one such fish thrown ashore. She was hard as a stick, in a strong salt shell.
This sea can become a source of wealth for the people. After all, this is a giant pantry of mineral salts.

Each liter of Dead Sea water contains 275 grams of potassium, sodium, bromine, magnesium, and calcium salts. Mineral reserves here are estimated at 43 billion tons. Bromine and potash can be mined extremely cheaply, and nothing limits the scale of production. The country has huge reserves of phosphates, which are in great demand on the world market, and their insignificant amount is mined.

General characteristics of the elements of the IIA-group.

The metals of the main subgroup of the second group (IIA-groups) include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), radium (Ra). These metals are called alkaline earth metals, since their Me (OH) 2 hydroxides have alkaline properties, and their MeO oxides are similar in their refractoriness to oxides heavy metals formerly called "lands".

Alkaline earth metals are s-elements. Metal atoms have two s-electrons (ns2) on the outer electron layer.

Basic information about the elements of the IIA group

	Be beryllium	mg magnesium	Ca calcium	Sr strontium	Ba barium	Ra radium
atomic number
The structure of the outer electron shells of atoms	where n = 2, 3, 4, 5, 6, 7, n is period number
Oxidation state
Basic natural compounds	3BeO Al2O3 6SiO2 (beryl); Be2SiO4 (phenacite)	2MgO SO2 (olivine); MgCO3 (magnesite); MgCO3 CaCO3 (dolomite); MgCl2 KCl 6H2O (karnal-lite)	CaCO3 (calcite), CaF2—fluorite, CaO Al2O3 6SiO2 (anorthite); CaSO4 2H2O (gypsum); MgCO3 CaCO3 (dolomite), Сa3(PO4)2 is phosphorite, Сa5(PO4)3Х (Х = F, Cl, OH) is apatite	SrCO3 (stront cyanite), SrSO4 (celestine)	BaCO3 (baterite) BaSO4 (barite, heavy spar)	As part of uranium ores

alkaline earth- lungs silvery white metals. Strontium has a golden hue, much harder alkali metals. Barium is similar in softness to lead. In air at normal temperature, the surface of beryllium and magnesium is covered with a protective oxide film. Alkaline earth metals actively interact with atmospheric oxygen, so they are stored under a layer of kerosene or in sealed vessels, like alkali metals.

Calcium is a simple substance

Physical Properties

Natural calcium is a mixture of stable isotopes. The most common calcium is 97%. Calcium is a silvery white metal; ρ = 1550 kg/m3, Тmelt = 839°С. Colors the flame orange-red.

Chemical properties

Interaction with simple substances (non-metals):

1. With halogens: Ca + Cl2 → CaCl2 (calcium chloride).

2. With carbon: Ca + 2C → CaC2 (calcium carbide).

3. With hydrogen: Ca + H2 → CaH2 (calcium hydride).

salt: CaCO3 calcium carbonate is one of the most common compounds on Earth: chalk, marble, limestone. The most important of these minerals is limestone. He himself is an excellent building stone, in addition, he is a raw material for the production of cement, slaked lime, glass, etc.

Roads are strengthened with lime gravel, and soil acidity is reduced with powder.

Natural chalk is the remains of shells of ancient animals. It is used as school crayons, as part of toothpastes, for the production of paper and rubber.

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Physical Properties

Iron is a silvery-white or gray metal, hard, with high ductility, thermal and electrical conductivity, refractory; ρ = 7874 kg/m3, Tm = 1540°C. Unlike other metals, iron can be magnetized, it has ferromagnetism.

Chemical properties

Iron interacts with both simple and complex substances.

The interaction of iron with oxygen

a) when heated (combustion), b) at n. y. (corrosion)

Chemical properties of iron

At n. at.	When heated
Reaction	3FeSO4 + 2K3 = Fe32↓ + 3K2SO4 (turbulene blue - dark blue precipitate).	1. 4FeCl3 + 3K4 = Fe43↓ + 12KCl (Prussian blue - dark blue precipitate). 2. FeCl3 + 3NH4CNS ⇆ Fe(CNS)3 + 3NH4Cl (fe blood-red thiocyanate + ammonia).

The biological role of iron

Biochemists reveal the huge role of iron in the life of plants, animals and humans. As part of hemoglobin, iron causes the red color of this substance, which, in turn, determines the color of the blood. The body of an adult contains 3 g of iron, of which 75% is part of hemoglobin, due to which the most important biological process, respiration, is carried out. Iron is also essential for plants. It participates in the oxidative processes of protoplasm, in the respiration of plants and in the construction of chlorophyll, although it is not included in its composition itself. Iron has long been used in medicine for the treatment of anemia, with exhaustion, loss of strength.