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Aluminum: chemical and physical properties

Some of the most convenient materials in processing are metals. Among them there are also their leaders. So, for example, the main properties of aluminum are known to people for a long time. They are so suitable for use in everyday life that this metal has become very popular. What are the properties of aluminum as a simple substance and as an atom, we consider in this article.

History of the discovery of aluminum

For a long time man knew the connection of the metal in question - alum - kali alum. It was used as a means capable of swelling and binding together the components of the mixture, this was also necessary for the manufacture of leather products. The existence of pure aluminum oxide became known in the XVIII century, in the second half. However, no pure substance was obtained.

He also managed to isolate the metal from his chloride for the first time by the scientist H. K. Oersted. It was he who treated the amalgam of potassium salt and isolated a mixture of gray powder, which was aluminum in its pure form.

Then it became clear that the chemical properties of aluminum are manifested in its high activity, strong reducing ability. Therefore, for a long time no one else worked with him.

However, in 1854 the Frenchman DeVille was able to obtain ingots of metal by electrolysis of the melt. This method is still relevant to this day. Especially the mass production of valuable material began in the twentieth century, when the problems of obtaining a large amount of electricity at the enterprises were solved.

To date, this metal - one of the most popular and used in construction and consumer industries.

General characteristics of the aluminum atom

If we characterize the element under consideration from the position in the periodic system, then we can distinguish several points.

  1. The serial number is 13.
  2. It is located in the third small period, the third group, the main subgroup.
  3. The atomic mass is 26.98.
  4. The number of valence electrons is 3.
  5. The configuration of the outer layer is expressed by the formula 3s 2 3p 1 .
  6. The name of the element is aluminum.
  7. Metallic properties are strongly pronounced.
  8. There are no isotopes in nature, they exist only in one form, with a mass number of 27.
  9. Chemical symbol - AL, in formulas is read as "aluminum".
  10. The degree of oxidation is one, equal to +3.

The chemical properties of aluminum are fully confirmed by the electronic structure of its atom, because having a large atomic radius and a small affinity for the electron, it is able to act as a strong reducing agent, like all active metals.

Aluminum as a simple substance: physical properties

If we talk about aluminum as a simple substance, then it is a silvery-white shiny metal. In air, it is rapidly oxidized and covered with a dense oxide film. The same thing happens with the action of concentrated acids.

The presence of such a feature makes the products made of this metal resistant to corrosion, which, naturally, is very convenient for people. Therefore, aluminum is so widely used in construction. The properties of the substance are also of interest because the metal is very light, yet durable and soft. A combination of such characteristics is not available to every substance.

There are several basic physical properties that are characteristic of aluminum.

  1. High degree of ductility and ductility. This metal is made of light, strong and very thin foil, it is also rolled into a wire.
  2. The melting point is 660 ° C.
  3. The boiling point is 2450 ° C.
  4. The density is 2.7 g / cm 3 .
  5. The crystal lattice is a volume, face-centered, metallic lattice.
  6. The type of connection is metallic.

The physical and chemical properties of aluminum determine the areas of its use and use. If we talk about the everyday aspects, then the characteristics we have examined above play an important role. As an easy, durable and anticorrosive metal, aluminum is used in aircraft and shipbuilding. Therefore, it is very important to know these properties.

Chemical properties of aluminum

From the point of view of chemistry, the metal in question is a strong reducing agent, which is capable of exhibiting high chemical activity, being a pure substance. The main thing is to remove the oxide film. In this case, activity sharply increases.

The chemical properties of aluminum as a simple substance are determined by its ability to react with:

  • Acids;
  • Alkalis;
  • Halogens;
  • Gray.

With water, it does not interact under normal conditions. In this case, from halogens without heating reacts only with iodine. For the remaining reactions, you need a temperature.

Examples can be given that illustrate the chemical properties of aluminum. Equations of interaction reactions with:

  • Acids - AL + HCL = AlCL 3 + H 2 ;
  • Alkalis - 2Al + 6H2O + 2NaOH = Na [Al (OH) 4 ] + 3H2;
  • Halogens - AL + Hal = ALHal 3 ;
  • Gray - 2AL + 3S = AL 2 S 3 .

In general, the most important property of the substance in question is the high ability to restore other elements from their compounds.

Reducing ability

Reducing properties of aluminum are well traced on reactions of interaction with oxides of other metals. He easily extracts them from the composition of matter and allows to exist in a simple form. For example: Cr 2 O 3 + AL = AL 2 O 3 + Cr.

In metallurgy, there is a whole method of obtaining substances, based on similar reactions. It was called aluminothermy. Therefore, in the chemical industry, this element is used specifically for the production of other metals.

Distribution in nature

In the prevalence of other metal elements, aluminum ranks first. It is 8.8% in the earth's crust. If to compare with nonmetals, its place will be the third, after oxygen and silicon.

Due to its high chemical activity, it does not occur in pure form, but only in the composition of various compounds. So, for example, many ores, minerals, rocks, which include aluminum, are known. However, it is extracted only from bauxites, the content of which in nature is not too great.

The most common substances containing the metal under consideration are:

  • Feldspars;
  • Bauxite;
  • Granites;
  • silica;
  • Aluminosilicates;
  • Basalts and others.

In a small amount, aluminum is necessarily part of the cells of living organisms. Some species of mice and sea creatures are able to accumulate this element within their body during their lifetime.


The physical and chemical properties of aluminum make it possible to obtain it only in one way: by electrolysis of the melt of the corresponding oxide. However, this process is technologically complex. The melting point of AL 2 O 3 exceeds 2000 0 C. Because of this, it is not directly possible to electrolyse it. Therefore, proceed as follows.

  1. They extract bauxite.
  2. They are cleaned of impurities, leaving only aluminum oxide.
  3. The cryolite is then melted.
  4. Add the oxide there.
  5. This mixture is electrolyzed and pure aluminum and carbon dioxide are obtained.

The yield of the product is 99.7%. However, it is possible to obtain even more pure metal, which is used for technical purposes.


The mechanical properties of aluminum are not so good as to apply it in pure form. Therefore, alloys based on this substance are most often used. There are many, you can name the most basic.

  1. Duralumin.
  2. Aluminum-manganese.
  3. Aluminum-magnesium.
  4. Aluminum-copper.
  5. Silumin.
  6. Avial.

Their main difference is, of course, third-party additives. In all the basis is aluminum. Other metals make the material more durable, resistant to corrosion, wear-resistant and pliable in processing.

There are several main areas of application of aluminum, both in pure form and in the form of its compounds (alloys).

  1. For the manufacture of wire and foil, used in everyday life.
  2. Making dishes.
  3. Aircraft construction.
  4. Shipbuilding.
  5. Construction and architecture.
  6. Space industry.
  7. Creation of reactors.

Along with iron and its alloys, aluminum is the most important metal. It is these two representatives of the periodic system that have found the most extensive industrial application in the hands of man.

Properties of aluminum hydroxide

Hydroxide is the most common compound that forms aluminum. Its chemical properties are the same as those of the metal itself - it is amphoteric. This means that it is capable of exhibiting a dual nature, reacting with both acids and alkalis.

Aluminum hydroxide itself is a white gelatinous precipitate. It is easy to obtain it by reacting an aluminum salt with an alkali or ammonium hydroxide. When reacted with acids, this hydroxide gives the usual corresponding salt and water. If the reaction proceeds with alkali, then hydroxyl complexes of aluminum are formed, in which its coordination number is 4. Example: Na [Al (OH) 4 ] - sodium tetrahydroxoaluminate.

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