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Metals that react easily are called active metals. These include alkali, alkaline earth metals and aluminum.
Position in the periodic table
The metallic properties of elements decrease from left to right in the periodic table. Therefore, elements of groups I and II are considered the most active.
Rice. 1. Active metals in the periodic table.
All metals are reducing agents and easily part with electrons at the outer energy level. Active metals have only one or two valence electrons. In this case, metallic properties increase from top to bottom with increasing number of energy levels, because The further an electron is from the nucleus of an atom, the easier it is for it to separate.
Alkali metals are considered the most active:
- lithium;
- sodium;
- potassium;
- rubidium;
- cesium;
- French
Alkaline earth metals include:
- beryllium;
- magnesium;
- calcium;
- strontium;
- barium;
- radium.
The degree of activity of a metal can be determined by the electrochemical series of metal voltages. The further to the left of hydrogen an element is located, the more active it is. Metals to the right of hydrogen are inactive and can only react with concentrated acids.
Rice. 2. Electrochemical series of voltages of metals.
The list of active metals in chemistry also includes aluminum, located in group III and to the left of hydrogen. However, aluminum is on the border of active and intermediately active metals and does not react with some substances under normal conditions.
Lithium
When making clarifications and considering the most electrochemically active element, it becomes obvious that lithium will take the leading position in terms of activity. The name of this element is translated as “stone” - this is due to the fact that it was discovered in petalite (mineral). The metal, which has a silvery color, sinks in water, but rests confidently on the surface of kerosene. In terms of electrochemical activity, this element surpasses all other alkaline elements, displacing other metals during chemical reactions. This main property of lithium is decisive for its other characteristics.
Lithium is a very important element for the normal functioning of the entire human body, but it is needed in small doses. With an increased concentration of lithium in the human body, poisoning can occur, while a reduced content can lead to mental instability in a person. Some drinks even promoted lithium as an excellent hangover cure. Perhaps this is not unreasonable, and lithium really helps to cope with malaise after drinking alcohol, but using it in high doses is not recommended for the above reasons.
Properties
Active metals are soft (can be cut with a knife), light, and have a low melting point.
The main chemical properties of metals are presented in the table.
| Reaction | The equation | Exception |
| Alkali metals spontaneously ignite in air when interacting with oxygen | K + O2 → KO2 | Lithium reacts with oxygen only at high temperatures |
| Alkaline earth metals and aluminum form oxide films in air and spontaneously ignite when heated | 2Ca + O2 → 2CaO | |
| React with simple substances to form salts | – Ca + Br2 → CaBr2; – 2Al + 3S → Al2S3 | Aluminum does not react with hydrogen |
| React violently with water, forming alkalis and hydrogen | – 2Na + 2H2O → 2NaOH + H2; – Ca + 2H2O → Ca(OH)2 + H2 | The reaction with lithium is slow. Aluminum reacts with water only after removing the oxide film |
| React with acids to form salts | – Ca + 2HCl → CaCl2 + H2; – 2K + 2HMnO4 → 2KMnO4 + H2 | |
| Interact with salt solutions, first reacting with water and then with salt | 2Na + CuCl2 + 2H2O: – 2Na + 2H2O → 2NaOH + H2; – 2NaOH + CuCl2 → Cu(OH)2↓ + 2NaCl |
Active metals easily react, so in nature they are found only in mixtures - minerals, rocks.
Rice. 3. Minerals and pure metals.
History of discovery
Its discovery belongs to the German researchers R. Bunsen and G. Kirchhoff. Even then, scientists were interested in which metals were active and which were not. In 1860, researchers studied the composition of water from the Durkheim Reservoir. They did this using spectral analysis. In the water sample, scientists found elements such as strontium, magnesium, lithium, and calcium.
They then decided to analyze the drop of water using a spectroscope. That's when they saw two bright blue lines located not far from each other. One of them, in its position, practically coincided with the line of the metal strontium. Scientists decided that the substance they identified was unknown and classified it as an alkali metal.
In the same year, Bunsen wrote a letter to his photochemist colleague G. Roscoe, in which he talked about this discovery. Cesium was officially reported on May 10, 1860 at a meeting of scientists at the Berlin Academy. After six months, Bunsen was able to isolate about 50 grams of cesium chloroplatinite. Scientists processed 300 tons of mineral water and isolated about 1 kg of lithium chloride as a byproduct to ultimately obtain the most active metal. This suggests that mineral waters contain very little cesium.
The difficulty of obtaining cesium constantly pushes scientists to search for minerals containing it, one of which is pollucite. But the extraction of cesium from ores is always incomplete; during operation, cesium dissipates very quickly. This makes it one of the most difficult to obtain substances in metallurgy. The earth's crust, for example, contains 3.7 grams of cesium per ton. And in one liter of sea water, only 0.5 μg of the substance represents the most active metal. This makes cesium extraction one of the most labor-intensive processes.
What have we learned?
Active metals include elements of groups I and II - alkali and alkaline earth metals, as well as aluminum. Their activity is determined by the structure of the atom - a few electrons are easily separated from the external energy level. These are soft light metals that quickly react with simple and complex substances, forming oxides, hydroxides, and salts. Aluminum is closer to hydrogen and its reaction with substances requires additional conditions - high temperatures, destruction of the oxide film.
How was cesium discovered?
The most active metal was the first chemical element, the presence of which in the surface of the earth's crust was discovered using the method of spectral analysis. When scientists received the spectrum of the metal, they saw two sky-blue lines in it. This is how this element got its name. The word caesius translated from Latin means “sky blue”.
Comparison of the most active metals
Ununennium is a metal that has not yet been discovered. It will occupy first place in the eighth row of the periodic table. The development and research of this element is carried out in Russia at the Joint Institute for Nuclear Research. This metal will also have to have very high activity. If we compare the already known francium and cesium, then francium will have the highest ionization potential - 380 kJ/mol.
For cesium this figure is 375 kJ/mol. But francium still does not react as quickly as cesium. Thus, cesium is the most active metal. This is an answer (chemistry is most often the subject in whose curriculum you can find a similar question), which can be useful both in a lesson at school and in a vocational school.
The most active metal with water
INTERACTION OF METALS WITH WATER
Water is a very weak electrolyte, however, in the process of dissociation of its molecules, although in small quantities, hydrogen ions are formed:
H2O
H + + OH -
The resulting H + ions are capable of oxidizing metal atoms located in the activity series up to hydrogen, being reduced to molecular hydrogen:
Consequently, the reduction product when any metal (if it is in the activity series to the left of hydrogen) interacts with water will be hydrogen gas. The composition of the oxidation product depends on the activity of the metal and the reaction conditions.
Active metals
interact vigorously with water under normal conditions according to the following scheme:
The product of metal oxidation is its hydroxide – Me(OH)n (where n is the oxidation state of the metal).
Intermediate activity metals
interact with water when heated according to the following scheme:
2Me + nH2O
Me2On + nH2
The oxidation product in such reactions is metal oxide Me 2 On (where n is the oxidation state of the metal).
3 Fe + 4 H 2 O steam
Fe 2 O 3 FeO + 4 H 2
Source
Receipt in Russia
As stated, the main mineral from which cesium is obtained is pollucite. This most active metal can also be obtained from rare avogadrite. Pollucite is used in industry. It was not mined in Russia after the collapse of the Soviet Union, despite the fact that even in those days gigantic reserves of cesium were discovered in the Voronya tundra near Murmansk.
By the time the domestic industry could afford the extraction of cesium, the license to develop this deposit was acquired by a company from Canada. Now cesium extraction is carried out by Novosibirsk.
Advantages and disadvantages
There are many advantages, but no less disadvantages.
| Advantages | Flaws |
| Easy machining | High density; products turn out heavy |
| Hardness, elasticity, strength - the best properties of alloys | Metal corrosion in the presence of moisture |
| The ability to obtain specified properties of alloys by adding a small amount of impurities | Tendency to electrochemical corrosion |
We recommend: MAGNESIUM – fiery metal
Malleability makes it possible to produce decorative products.
Application
The general chemical properties of metals are used to create alloys, detergents, and are used in catalytic reactions. Metals are present in batteries, electronics, and supporting structures.
The main areas of application are listed in the table.
| Industry | Production | Metals |
| Chemical industry | Catalysts, salts, alkalis | Pt, Fe, Ni, K |
| Food industry | Table salt (NaCl), soda (Na2CO3, NaHCO3) | Na, Ca, Ag |
| Metallurgy | Alloys, coatings, parts of various shapes, wire, cladding, building materials and tools | Fe, Cr, Ni, W, Mo |
| Instrumentation | Microcircuits, photocells, sensors | Cs, Co, Ni, Cu |
| Jewelry industry | Decorations | Au, Pt, Ag |
| Medicine | Prostheses | Ti, Ni, Au |
Rice. 3. Bismuth.
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Francium metal
Another of the metals with the most intense properties is francium. It got its name in honor of the homeland of the discoverer of metal. M. Peret, born in France, discovered a new chemical element in 1939. It is one of those elements about which even chemist researchers themselves find it difficult to draw any conclusions.
Francium is the heaviest metal. Moreover, the most active metal is francium, along with cesium. Francium has this rare combination of high chemical activity and low nuclear resistance. Its longest-lived isotope has a half-life of only 22 minutes. Francium is used to detect another element, sea anemone. Francium salts were also previously proposed to be used to detect cancer tumors. However, due to its high cost, this salt is not profitable to produce.
Uses of cesium
This metal is used to make various solar cells. Cesium compounds are also used in special branches of optics - in the manufacture of infrared devices and night vision binoculars. Cesium is used in the manufacture of sights that allow you to notice enemy equipment and manpower. It is also used for the manufacture of special metal halide lamps.
But this does not exhaust the range of its application. A number of medical preparations have also been created based on cesium. These are medications for the treatment of diphtheria, peptic ulcers, shock and schizophrenia. Like lithium salts, cesium salts have normothimic properties - or, simply, they are able to stabilize the emotional background.
