One of the most convenient materials in processing is metals. Among them also have their own leaders. For example, the basic properties of aluminum have been known to people for a long time. They are so suitable for domestic use 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
It has long been known to man the compound of the metal in question - potassium alum. It was used as a means that could swell and bind together the components of the mixture, it was also necessary when dressing leather products. The existence of pure aluminum oxide became known in the 18th century, in its second half. However, no pure substance was obtained.
The scientist H.K. Oersted was able to isolate the metal from its chloride for the first time. It was he who treated the potassium amalgam with salt and isolated gray powder from the mixture, which was pure aluminum.
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 metal ingots by melt electrolysis. This method is relevant to this day. Especially mass production of valuable material began in the 20th century, when the problems of obtaining large amounts of electricity at enterprises were solved.
Today, this metal is one of the most popular and used in construction and household industries.
General characteristic of an aluminum atom
If we characterize the element under consideration by position in the periodic system, we can distinguish several points.
- The serial number is 13.
- It is located in the third small period, the third group, the main subgroup.
- The atomic mass is 26.98.
- The number of valence electrons is 3.
- The configuration of the outer layer is expressed by the formula 3s 2 3p 1 .
- The name of the element is aluminum.
- Metallic properties are strongly expressed.
- It does not have isotopes in nature, exists in only one form, with a mass number of 27.
- The chemical symbol is AL, read in the formulas as "aluminum."
- The oxidation state 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 low electron affinity, 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 silver-white shiny metal. It rapidly oxidizes in air and becomes covered with a dense oxide film. The same thing happens with concentrated acids.
The presence of such a feature makes products made of this metal resistant to corrosion, which, of course, is very convenient for people. Therefore, aluminum finds such wide application in construction. The properties of the substance are also interesting in that this metal is very light, while being durable and soft. The combination of such characteristics is not available to every substance.
Several basic physical properties that are characteristic of aluminum can be distinguished.
- High degree of ductility and ductility. This metal is used to make light, strong and very thin foil; it is also rolled into wire.
- Melting point - 660 0 C.
- Boiling point - 2450 0 .
- Density - 2.7 g / cm 3 .
- The crystal lattice is volume face-centered, metal.
- Type of connection - metal.
The physical and chemical properties of aluminum determine the scope of its application and use. If we talk about everyday life, then the characteristics already considered by us above play a large role. As a light, durable and anti-corrosion metal, aluminum is used in aircraft and shipbuilding. Therefore, these properties are very important to know.
Chemical properties of aluminum
From the point of view of chemistry, the metal in question is a strong reducing agent that is capable of exhibiting high chemical activity, being a pure substance. The main thing is to eliminate the oxide film. In this case, the activity increases sharply.
The chemical properties of aluminum as a simple substance are determined by its ability to react with:
- acids;
- alkalis;
- halogens;
- gray.
It does not interact with water under normal conditions. Moreover, it reacts only with iodine from halogens without heating. For other reactions, temperature is needed.
Examples can be given illustrating the chemical properties of aluminum. The equations of reactions of interaction with:
- acids - AL + HCL = AlCL 3 + H 2 ;
- alkalis - 2Al + 6H 2 O + 2NaOH = Na [Al (OH) 4 ] + 3H 2 ;
- halogens - AL + Hal = ALHal 3 ;
- gray - 2AL + 3S = AL 2 S 3 .
In general, the most important property of the substance in question is its high ability to restore other elements from their compounds.
Recovery ability
The reducing properties of aluminum are well seen in reactions with other metal oxides. It easily extracts them from the composition of the substance and allows it to exist in a simple form. For example: Cr 2 O 3 + AL = AL 2 O 3 + Cr.
In metallurgy, there is a whole technique for producing substances based on similar reactions. It is called aluminothermy. Therefore, in the chemical industry, this element is used specifically for the production of other metals.
Spread in nature
In terms of prevalence among other metal elements, aluminum is in first place. Its in the earth's crust contains 8.8%. If compared with non-metals, then its place will be third, after oxygen and silicon.
Due to its high chemical activity, it is not found in its pure form, but only in the composition of various compounds. For example, many ores, minerals, rocks, which include aluminum, are known. However, it is mined only from bauxites, the content of which in nature is not too high.
The most common substances containing the metal in question:
- 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 plunders and marine inhabitants are able to accumulate this element inside their body during life.
Getting
The physical and chemical properties of aluminum make it possible to obtain it in only one way: by electrolysis of the melt of the corresponding oxide. However, this process is technologically complicated. The melting point of AL 2 O 3 exceeds 2000 0 C. Because of this, it cannot be directly subjected to electrolysis. Therefore, proceed as follows.
- Bauxites are mined.
- They clean them from impurities, leaving only aluminum oxide.
- Then melted cryolite.
- Oxide is added there.
- This mixture is electrolyzed to give pure aluminum and carbon dioxide.
The product yield is 99.7%. However, it is possible to obtain even more pure metal, which is used for technical purposes.
Application
The mechanical properties of aluminum are not so good as to be used in pure form. Therefore, alloys based on this substance are most often used. There are many of them, the most basic ones can be called.
- Duralumin.
- Aluminum-manganese.
- Aluminum-magnesium.
- Aluminum-copper.
- Silumins.
- Air.
Their main difference is, of course, third-party additives. In all, aluminum is the basis. Other metals make the material more durable, resistant to corrosion, wear-resistant and malleable in processing.
We can name several main areas of application of aluminum both in pure form and in the form of its compounds (alloys).
- For the manufacture of wire and foil used in everyday life.
- Making dishes.
- Aircraft manufacturing.
- Shipbuilding.
- Construction and architecture.
- Space industry.
- The creation of reactors.
Together 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, entering into reactions with both acids and alkalis.
Aluminum hydroxide per se is a white gelatinous precipitate. It is easy to obtain it by the interaction of an aluminum salt with alkali or ammonium hydroxide. When reacted with acids, this hydroxide gives the usual appropriate salt and water. If the reaction is with alkali, then aluminum hydroxocomplexes are formed in which its coordination number is 4. Example: Na [Al (OH) 4 ] - sodium tetrahydroxoaluminate.