Aluminum - chemical element Group III Periodic Table of Elements D.I. Mendeleev. Due to its high chemical activity, aluminum is found in nature only in bound form. In terms of content in the earth's crust, it (in the form of its compounds) ranks first among metals - 8.13% and third place after oxygen and silicon. According to academician A.E. Fersman, there are more than 250 aluminum minerals, which are mainly concentrated near the earth's surface, and more than 40% of them are aluminosilicates.
Almost the only method for producing aluminum metal is electrolysis of cryolite-alumina melt. The main raw material for this process - alumina (A1 2 O 3) is obtained by various hydrochemical methods by processing minerals containing aluminum compounds.

Atomic structure and crystal lattice

In the Periodic System D.I. The Mendeleev atomic number of aluminum is 13, its atomic mass is 26.9815 (for carbon 12 C) and 26.98974 (for oxygen 16 O).

The main isotope is 27 A1, which is stable and consists of 14 neutrons and 13 protons. In addition to one isotope 26 A1, whose half-life is 10 6 years, the existence of six more isotopes with mass numbers 23, 24, 25, 26, 28 and 29 and with short half-lives (from 0.13 to 396 s) has been established, as well as negligible low prevalence in nature (from 2×10 -5 to 1.5×10 -4%).

Aluminum is trivalent, and its 13 electrons are distributed in electron shells l s 2 , 2s 2 , 2р 6, 3s 2 , 3r 1. On the outer electronic layer M there are three valence electrons: two in Z s-orbit with ionization potentials of 1800 and 2300 kJ/mol and one at 3 p-orbit with a potential of 574.5 kJ/mol, and therefore in chemical compounds aluminum is usually trivalent (A1 3+). Since the electron is p-orbit with the nucleus of the atom is connected weaker than two paired electrons in the s-orbit, then under certain conditions, losing a p-electron, the aluminum atom becomes a monovalent ion (A1 +), forming compounds of lower valence (subconnections), and even less often - A1 2+.

Crystal lattice aluminum is a face-centered cube, which is stable at temperatures from 4°K to the melting point. There are no allotropic transformations in aluminum, i.e. its structure is permanent. The unit cell consists of four atoms measuring 4.049596×10 -10 m; at 25 °C atomic diameter ( shortest distance between atoms in the lattice) is 2.86×10 -10 m, and the atomic volume 9.999×10 -6 m 3 /g-atom. Impurities in aluminum have little effect on the lattice parameter.

Aluminum has great chemical activity; the energy of formation of its compounds with oxygen, sulfur and carbon is very high. In the voltage series it is among the most electronegative elements, and its normal electrode potential is -1.67 V. normal conditions, interacting with atmospheric oxygen, aluminum is covered with a thin (2-10 -5 cm) but durable film of aluminum oxide A1 2 0 3, which protects against further oxidation, which determines its high corrosion resistance. However, if present in aluminum or environment Hg, Na, Mg, Ca, Si, Cu and some other elements, the strength of the oxide film and its protective properties are sharply reduced.

Molten aluminum reacts actively with carbon oxide and dioxide and water vapor. The solubility of hydrogen in aluminum is of greatest interest, since the presence of hydrogen in the metal negatively affects mechanical properties aluminum and its alloys. Hydrogen in aluminum in quantities exceeding its solubility in the solid state is considered a harmful impurity.

Aluminum has amphoteric properties, i.e. reacting with acids, it forms the corresponding salts, and when interacting with alkalis, aluminates. This feature significantly expands the possibilities of extracting aluminum from ores of various compositions. Aluminum dissolves in sulfuric acid and hydrochloric acids, as well as in alkalis, but concentrated nitric and organic acids have no effect on aluminum.

Lesson summary on the topic

"Aluminum"

Goals:

n Give an idea of ​​the structure of the aluminum atom based on its position in the PSCE, physical and chemical properties simple substance aluminum and its occurrence in nature

n Summarize students’ knowledge about the use of aluminum, its compounds and alloys in the national economy

n Discuss the importance of aluminum in the human body

7) Application of aluminum and its compounds (generalization of knowledge, checking notes)

Game: select objects made of aluminum and explain what properties the person used in their manufacture

structural material (lightness, malleability for stamping, corrosion resistance); production kitchen utensils, aluminum foil (non-toxic, high thermal conductivity);

· production of wires (lightness, electrical conductivity). The electrical conductivity of aluminum is only 1.7 times less than that of copper, while aluminum is approximately 2 times cheaper. True, aluminum as an electrical material has unpleasant property- due to the strong oxide film it is difficult to solder;

manufacturing mirrors (high reflectivity combined with low cost and ease of spraying); jewelry(when aluminum was very expensive, a variety of jewelry was made from it. The fashion for them immediately passed when new technologies for its production appeared, which reduced the cost many times. Nowadays aluminum is sometimes used in the production of costume jewelry); aluminum is registered as food additives E173 (dye group); highly efficient rocket fuel; silver paint (shine in powder); restores metals from their oxides (aluminothermy); Aluminum chloride AlCl3 is used as a catalyst (?) in the production of many organic substances

8) Aluminum in the human body

The human body receives from 5 to 50 mg of aluminum daily

When hot processing of food products due to the use of aluminum cookware, food contamination with this metal occurs

Aluminum also enters the body with food, drinking water, through the lungs, medicines, deodorants

Deposited in bones, liver, lungs and gray matter of the brain

With age, aluminum content in the lungs and brain increases

Attention! Danger! In high concentrations, aluminum has a negative effect on nervous system and can cause convulsions, decrease or loss of memory, contributes to the development of senile atherosclerosis, development slows down in children, the stomach and intestines are affected. In this case, nettle, horsetail, and preparations containing succinic acid will help.

Handout for parents:"Aluminum is permanent integral part cells. IN small quantities It is necessary for humans, but in case of excess, this metal can pose a serious health hazard. Aluminum enters the body with food, water, deodorants, and from aluminum cookware. Therefore, store and cook dairy dishes, cabbage soup, compotes, salted fish, pickled vegetables and mushrooms in such containers. sauerkraut This is impossible, since in an acidic environment aluminum gradually dissolves and partially passes into products.”

4. Consolidation of acquired knowledge

1) Test with mutual verification “Which statements are true?”

1. Aluminum occurs in nature only in the form of compounds (+)

2. Silumin - an alloy of aluminum with sulfur (-)

3. Aluminum atoms exhibit reducing properties (+)

4. Aluminum is a poor conductor of electricity (-)

5. Aluminum can react with both acids and alkalis (+)

6. If in excess, aluminum can pose a serious health hazard (+)

7. Global aluminum production is constantly decreasing (-)

2) Guess the puzzle:

5. Homework

Required:§ 13 pp. 68-74, ? 1, 4 p. 75, complete the lesson notes

Additional: 1) Write down the equations for the chemical reactions of aluminum with bromine, sulfur and carbon. Consider them from the point of view of OVR. 2) ? 5 p.75

Creative: wrote the poem "Autumn" in 1959, in which he used aluminum as an artistic image: ...And outside the window in the young frost lie fields of aluminum... Explain what properties of aluminum the poet meant. Create beautiful figurative expressions using the properties of aluminum that can be used in essay writing.

6. End of lesson

7. Reflection

Sources of information:

1. Gabrielyan, . 9th grade: educational. For general education institutions / . – M.: Bustard, 2008. – 270 p.

2. Akopyan, V. Not all that glitters is good (article) / V. Akopyan // Bulletin of healthy lifestyle. – 2004. - No. 1.

3. http://ru. wikipedia. org/wiki/ - aluminum, natural compounds and alloys of aluminum and their applications

4. http://**/naz_factory. aspx - Nadvoitsky aluminum smelter

“Aluminum metal” - Aluminum salts (aluminates). Physical properties. Interaction with water. When interacting with dilute acids, aluminum forms salts. It was first obtained by the Danish physicist Oersted in 1925. Interaction with non-metals. Interaction with alkalis. Interaction with oxygen. Reacts with halogens under normal conditions.

"Aluminum metal" - Physical properties. Answer the question: “Why is aluminum called the metal of the future?” Chemical properties. An aluminum cup has become more expensive than a gold one. For the first time he produced aluminum industrially (1855). Al. Aluminum is the metal of the future. Study the properties of group 3 A metals using aluminum as an example. "Silver from clay."

“The atom and its structure” - Example: The polonium atom has a mass number of 210. The composition of the atomic nucleus.", develop practical problem-solving skills. Educational: repeat, generalize and systematize theoretical knowledge on the topics: "Structure of atoms. It should follow from this that atoms are not stable entities.

“Structure of the electron shell” - - The energy level consists of orbitals. 3. The mass of an atom consists of the number of protons and neutrons. Phosphorus. D – orbital. The structure of the electron shell. Group. Repetition. Knowledge test. The group number coincides with the number of electrons on the last energy level. Return to the topic of the lesson. 3d0.

Physical properties :

General chemical properties

Occurrence in nature

Application

Consolidation and testing of knowledge Test questions

List the alkali metals. Why are they called that?

What are the structural features of alkali metal atoms?

What is the oxidation state of the alkali metal in the compound? Why?

What are physical properties alkali metals?

Which alkali metal is the most active and why?

What reactions are characteristic of alkali metals?

What oxides and peroxides are produced by the oxidation of alkali metals?

How do alkali metal atoms and ions color the flame?

Which chemical bonds do they form alkali metals with nonmetals?

How can alkali metals be obtained?

Where are alkali metals used?

What elements form alkaline earth metals?

Where in periodic table are these elements located?

What are the structural features of the atoms of these metals?

What oxidation state is characteristic of alkali-emel elements in compounds?

What are the physical properties of calcium, magnesium?

How should these metals be stored?

How can these metals be obtained?

List the reactions characteristic of these metals.

What is the structure of the aluminum atom?

What is the oxidation state of aluminum in the compounds? Why?

Name the most important natural compounds of aluminum.

What are the physical properties of aluminum?

How does aluminum behave in chemical reactions? Why?

What acids does aluminum not react with?

How does aluminum interact with alkalis?

What metals can aluminum reduce from salts or oxides?

What reactions prove the amphoteric nature of aluminum oxide and hydroxide?

What happens to aluminum hydroxide when heated?