What is characteristic of sodium. Characteristics of sodium. Sodium formula. Signs of excess sodium

Natron was originally called sodium hydroxide. In 1807, Davy, by electrolysis of slightly moistened solid alkalis, obtained free metals - potassium and sodium, calling them potassium and sodium. Berzelius and then Hess in Russia proposed the name Natrium, which stuck.

Being in nature, receiving:

Alkali metals are not found in free form in nature. Sodium is part of various compounds. The most important is the compound of sodium with chlorine NaCl, which forms rock salt deposits (Donbass, Solikamsk, Sol-Iletsk, etc.). Sodium chloride is also found in sea water and salt springs. Sodium is one of the common elements. The sodium content in the earth's crust is 2.64%.
Produced by electrolysis of molten sodium chloride or sodium hydroxide. The reduction of its oxides, chlorides, and carbonates with aluminum, silicon, calcium, and magnesium when heated in a vacuum is also used.

Physical properties:

Sodium is a silvery-white metal, its density is 0.97 g/cm3, very soft, easy to cut with a knife. There is a metallic bond between atoms. A substance with such a bond is characterized by metallic luster, ductility, softness, good electrical conductivity and thermal conductivity.

Chemical properties:

During a chemical interaction, a sodium atom easily gives up valence electrons, becoming a positively charged ion. It oxidizes quickly in air, so it is stored under a layer of kerosene.
When burned in excess oxygen, it forms sodium peroxide, Na 2 O 2
With hydrogen when heated, it forms the hydride Na + H 2 = 2NaH
Easily interacts with many non-metals - halogens, sulfur, phosphorus, etc.
Reacts violently with water: 2Na + 2H 2 O = 2NaOH + H 2

The most important connections:

Sodium oxide, Na 2 O (colorless), reacts with water vapor and carbon dioxide, so it is better to store it in anhydrous benzene.
When sodium reacts directly with oxygen, a mixture of sodium oxide and sodium peroxide is obtained. To obtain pure oxide, you can use the reaction: Na 2 O 2 + 2Na = 2Na 2 O
Sodium peroxide, Na 2 O 2 (yellow) crystalline substance with an ionic lattice, interacts with moist carbon dioxide in the air, releasing oxygen: 2Na 2 O 2 + 2CO 2 = 2Na 2 CO 3 + O 2
Sodium hydroxide, NaOH is a crystalline white substance, relatively fusible, and very thermally stable. When heated, it evaporates without loss of water. It dissolves well in water and alcohols.
Sodium halides, colorless crystalline substances, highly soluble in water, with the exception of NaF. They are characterized by restorative properties.
Sodium sulfide, - Na 2 S. Colorless crystalline substance with an ionic lattice. It is highly soluble in water and is a strong reducing agent.
Salts, all salts are highly soluble and are strong electrolytes.
Sodium hydride, NaH is a colorless crystalline substance with a NaCl-type crystal lattice, the anion is H - . Prepared by passing hydrogen over molten metal. Subject to thermal dissociation without melting, easily decomposed by water:
2NaH = 2Na + H2
NaH + H 2 O = NaOH + H 2

Application:

Sodium compounds are the most important components of chemical production. Used in soap making, glass production, and household chemicals.
Sodium is important for most life forms, including humans. In living organisms, sodium ions together with potassium ions act as nerve impulse transmitters. Also, its ions play an important role in maintaining the body’s water regime.

Bondareva Maria Alexandrovna
HF Tyumen State University, 561 group.

Sources: G.P. Khomchenko "A manual on chemistry for those entering universities"
"Inorganic chemistry in diagrams and tables"

-element the main subgroup of the first group, the third period of the periodic system of chemical elements of D.I. Mendeleev, with atomic number 11. Denoted by the symbol Na (lat. Natrium). The simple substance sodium (CAS number: 7440-23-5) is a soft alkali metal of silvery-white color.

History and origin of the name

Sodium atom diagram

Sodium (or rather, its compounds) has been used since ancient times. For example, soda (natron), found naturally in the waters of soda lakes in Egypt. The ancient Egyptians used natural soda for embalming, bleaching canvas, cooking food, and making paints and glazes. Pliny the Elder writes that in the Nile Delta, soda (it contained a sufficient proportion of impurities) was isolated from river water. It went on sale in the form of large pieces, colored gray or even black due to the admixture of coal.

Sodium was first obtained by the English chemist Humphry Davy in 1807 by electrolysis of solid NaOH.

The name "sodium" comes from the Arabic natrun in Greek - nitron and originally it referred to natural soda. The element itself was previously called Sodium.

Receipt

The first way to produce sodium was the reduction reaction sodium carbonate coal when heating a close mixture of these substances in an iron container to 1000°C:

Na 2 CO 3 +2C=2Na+3CO

Then another method of producing sodium appeared - electrolysis of molten sodium hydroxide or sodium chloride.

Physical properties

Qualitative determination of sodium using a flame - bright yellow color of the emission spectrum of the “sodium D-line”, doublet 588.9950 and 589.5924 nm.

Sodium is a silvery-white metal, in thin layers with a purple tint, plastic, even soft (easily cut with a knife), a fresh cut of sodium is shiny. The electrical and thermal conductivity values ​​of sodium are quite high, the density is 0.96842 g/cm³ (at 19.7° C), the melting point is 97.86° C, and the boiling point is 883.15° C.

Chemical properties

An alkali metal that oxidizes easily in air. To protect against atmospheric oxygen, metallic sodium is stored under a layer kerosene. Sodium is less active than lithium, therefore with nitrogen reacts only when heated:

2Na + 3N 2 = 2NaN 3

When there is a large excess of oxygen, sodium peroxide is formed

2Na + O 2 = Na 2 O 2

Application

Sodium metal is widely used in preparative chemistry and industry as a strong reducing agent, including in metallurgy. Sodium is used in the production of highly energy-intensive sodium-sulfur batteries. It is also used in truck exhaust valves as a heat sink. Occasionally, sodium metal is used as a material for electrical wires intended to carry very high currents.

In an alloy with potassium, as well as with rubidium and cesium used as a highly efficient coolant. In particular, the alloy composition is sodium 12%, potassium 47 %, cesium 41% has a record low melting point of −78 °C and has been proposed as a working fluid for ion rocket engines and a coolant for nuclear power plants.

Sodium is also used in high and low pressure discharge lamps (HPLD and LPLD). NLVD lamps of the DNaT (Arc Sodium Tubular) type are very widely used in street lighting. They give off a bright yellow light. The service life of HPS lamps is 12-24 thousand hours. Therefore, gas-discharge lamps of the HPS type are indispensable for urban, architectural and industrial lighting. There are also lamps DNaS, DNaMT (Arc Sodium Matte), DNaZ (Arc Sodium Mirror) and DNaTBR (Arc Sodium Tubular Without Mercury).

Sodium metal is used in the qualitative analysis of organic matter. The alloy of sodium and the test substance is neutralized ethanol, add a few milliliters of distilled water and divide into 3 parts, J. Lassaigne's test (1843), aimed at determining nitrogen, sulfur and halogens (Beilstein test)

Sodium chloride (table salt) is the oldest used flavoring and preservative.
- Sodium azide (Na 3 N) is used as a nitriding agent in metallurgy and in the production of lead azide.
- Sodium cyanide (NaCN) is used in the hydrometallurgical method of leaching gold from rocks, as well as in the nitrocarburization of steel and in electroplating (silvering, gilding).
- Sodium chlorate (NaClO 3) is used to destroy unwanted vegetation on railway tracks.

Biological role

In the body, sodium is found mostly outside the cells (about 15 times more than in the cytoplasm). This difference is maintained by the sodium-potassium pump, which pumps out sodium trapped inside the cell.

Together withpotassiumsodium performs the following functions:
Creating conditions for the occurrence of membrane potential and muscle contractions.
Maintaining blood osmotic concentration.
Maintaining acid-base balance.
Normalization of water balance.
Ensuring membrane transport.
Activation of many enzymes.

Sodium is found in almost all foods, although the body gets most of it from table salt. Absorption mainly occurs in the stomach and small intestine. Vitamin D improves the absorption of sodium, however, excessively salty foods and foods rich in protein interfere with normal absorption. The amount of sodium taken in from food shows the sodium content in the urine. Sodium-rich foods are characterized by accelerated excretion.

Sodium deficiency in the dieter balanced food does not occur in humans, however, some problems can arise with vegetarian diets. Temporary deficiency may be caused by diuretic use, diarrhea, excessive sweating, or excess water intake. Symptoms of sodium deficiency include weight loss, vomiting, gas in the gastrointestinal tract, and impaired absorption amino acids and monosaccharides. Long-term deficiency causes muscle cramps and neuralgia.

Excess sodium causes swelling of the legs and face, as well as increased excretion of potassium in the urine. The maximum amount of salt that can be processed by the kidneys is approximately 20-30 grams; any larger amount is life-threatening.

Sodium in its pure form was obtained in 1807 by Humphry Davy, an English chemist who discovered sodium shortly before. Davy carried out the process of electrolysis of one of the sodium compounds - hydroxide, by melting which he obtained sodium. Humanity has been using sodium compounds since ancient times; soda of natural origin was used back in Ancient Egypt (calorizator). Named the element sodium (sodium) , sometimes this very name can be found even now. The usual name is sodium (from the Latin sodium- soda) was proposed by the Swede Jens Berzelius.

Sodium is an element of group I of III of the third period of the periodic table of chemical elements D.I. Mendeleev, has an atomic number of 11 and an atomic mass of 22.99. The accepted designation is Na(from Latin sodium).

Being in nature

Sodium compounds are found in the earth's crust and sea water as an impurity that tends to color rock salt blue due to the action of radiation.

Sodium is a soft, malleable alkali metal that is silvery-white in color and shiny when cut fresh (it is quite possible to cut sodium with a knife). When pressure is applied, it turns into a transparent red substance; at normal temperatures it crystallizes. When interacting with air, it quickly oxidizes, so sodium must be stored under a layer of kerosene.

Daily sodium requirement

Sodium is an important microelement for the human body; the daily requirement for adults is 550 mg, for children and adolescents - 500-1300 mg. During pregnancy, the sodium norm per day is 500 mg, and in some cases (excessive sweating, dehydration, taking diuretics) should be increased.

Sodium is found in almost all seafood (crayfish, crabs, octopus, squid, mussels, seaweed), fish (anchovies, sardines, flounder, smelt, etc.), chicken eggs, cereals (buckwheat, rice, pearl barley, oatmeal, millet), legumes (peas, beans), vegetables (tomatoes, celery, carrots, cabbage, beets), dairy products and meat by-products.

Beneficial properties of sodium and its effect on the body

The beneficial properties of sodium for the body are:

• Normalization of water-salt metabolism;
• Activation of enzymes of the salivary and pancreas;
• Participation in the production of gastric juice;
• Maintaining normal acid-base balance;
• Generating functions of the nervous and muscular system;
• Vasodilator effect;
• Maintaining blood osmotic concentration.

Sodium digestibility

Sodium is found in almost all foods, although the body receives most of it (about 80%) from. Absorption mainly occurs in the stomach and small intestine. improves the absorption of sodium, however, excessively salty foods and foods rich in proteins interfere with normal absorption.

Interaction with others

The use of sodium metal is in the chemical and metallurgical industries, where it acts as a powerful reducing agent. Sodium chloride (table salt) is used by all inhabitants of our planet without exception; it is the most famous flavoring agent and the oldest preservative.

Signs of sodium deficiency

Sodium deficiency usually occurs due to excessive sweating - in hot climates or during physical activity. A lack of sodium in the body is characterized by memory impairment and loss of appetite, dizziness, fatigue, dehydration, muscle weakness, and sometimes cramps, skin rashes, stomach cramps, nausea, and vomiting.

Signs of excess sodium

An excessive amount of sodium in the body makes itself felt by constant thirst, swelling and allergic reactions.

After all this, is it any wonder that sodium production continues to increase?

We end our story about element No. 11 with the words of Dmitry Ivanovich Mendeleev, written many years ago, but doubly true for our days: “The production of metallic sodium is one of the most important discoveries in chemistry, not only because through it the concept of simple bodies expanded and became more correct , but especially because sodium exhibits chemical properties that are only weakly expressed in other well-known metals.”

A detailed account of the chemical properties of sodium is omitted for the reason that this is one of the few sections of chemistry that are presented quite fully in school textbooks.

• SODIUM ON A SUBMARINE. Na melts at 98, but boils only at 883°C. Consequently, the temperature range of the liquid state of this element is quite large. That is why (and also due to the small neutron capture cross section) sodium began to be used in nuclear energy as a coolant. In particular, American nuclear submarines are equipped with power plants with sodium circuits. The heat generated in the reactor heats the liquid sodium, which circulates between the reactor and the steam generator. In the steam generator, sodium, when cooled, evaporates water, and the resulting high-pressure sodium rotates the steam turbine. For the same purposes, an alloy of sodium and potassium is used.
• INORGANIC PHOTOSYNTHESIS. Usually, when sodium is oxidized, an oxide of the composition Na 2 O is formed. However, if sodium is burned in dry air at an elevated temperature, then instead of the oxide, peroxide Na 2 O 2 is formed. This substance easily gives up its “extra” oxygen atom and therefore has strong oxidizing properties. At one time, sodium peroxide was widely used to bleach straw hats. Now the proportion of straw hats in the use of sodium peroxide is negligible; its main quantities are used for bleaching paper and for air regeneration in submarines. When sodium peroxide interacts with carbon dioxide, the process opposite to respiration occurs: 2Na 2 O 2 + 2CO 2 → 2Na 2 CO 3 + O 2, i.e. carbon dioxide is bound and oxygen is released. Just like a green leaf!
• SODIUM AND GOLD. By the time No. 11 was discovered, alchemy was no longer in favor, and the idea of ​​​​turning sodium into gold did not excite the minds of natural scientists. However, now a lot of sodium is consumed to obtain gold. “Gold ore” is treated with a solution of sodium cyanide (and it is obtained from elemental sodium). In this case, gold is converted into a soluble complex compound, from which it is isolated with the help of zinc. Gold miners are among the main consumers of element No. 11. On an industrial scale, Na cyanide is produced by the interaction of sodium, ammonia and coke at a temperature of about 800°C.
• SODIUM WIRE. The electrical conductivity of sodium is three times lower than that of copper. But sodium is 9 times lighter! It turns out that sodium wires are more profitable than copper wires. Of course, thin wires are not made from sodium, but it is advisable to make busbars for high currents from sodium. These tires are steel pipes welded at the ends and filled with sodium inside. Such tires are cheaper than copper ones.

• SODIUM IN WATER. Every schoolchild knows what happens if you throw a piece of sodium into water. More precisely, not into water, but onto water, because sodium is lighter than water. The heat released when sodium reacts with water is enough to melt the sodium. And now a sodium ball runs through the water, driven by the released hydrogen. However, the reaction of sodium with water is not only dangerous fun; on the contrary, it is often useful. Sodium is used to reliably remove traces of water from transformer oils, alcohols, ethers and other organic substances, and with the help of sodium amalgam (i.e., an alloy of sodium with mercury), the moisture content in many compounds can be quickly determined. Amalgam reacts with water much more calmly than sodium itself. To determine moisture content, a certain amount of sodium amalgam is added to a sample of organic matter and the moisture content is determined by the volume of hydrogen released.
• SODIUM BELT OF THE EARTH. It is quite natural that Na is never found in a free state on Earth - this metal is too active. But in the upper layers of the atmosphere - at an altitude of about 80 km - a layer of atomic sodium was discovered. At this altitude there is virtually no oxygen, water vapor, or anything at all for sodium to react with. Sodium was also discovered in interstellar space using spectral methods.
• ISOTOPES OF SODIUM. Natural sodium consists of only one isotope with a mass number of 23. There are 13 known radioactive isotopes of this element, two of which are of significant scientific interest. Sodium-22, when decaying, emits positrons - positively charged particles whose mass is equal to the mass of electrons. This isotope with a half-life of 2.58 years is used as a positron source. And the isotope sodium-24 (its half-life is about 15 hours) is used in medicine for the diagnosis and treatment of some forms of leukemia - a serious blood disease.

How do you get sodium?

A modern electrolyzer for producing sodium is a rather impressive structure that looks like a furnace. This “stove” is made of refractory brick and is surrounded on the outside by a steel casing. A graphite anode is inserted from below through the bottom of the electrolyzer, surrounded by a ring-shaped mesh - a diaphragm. This mesh prevents sodium from penetrating into the anode space, where chlorine is released. Otherwise, element No. 11 would burn in chlorine. The anode, by the way, is also ring-shaped. It is made of steel. A mandatory accessory for the electrolyzer is two caps. One is installed above the anode to collect chlorine, the other above the cathode to remove sodium.

A mixture of thoroughly dried sodium chloride and calcium chloride is loaded into the electrolyzer. This mixture melts at a lower temperature than pure sodium chloride. Electrolysis is usually carried out at a temperature of about 600°C.

The electrodes are supplied with a direct current of about 6 V; At the cathode, Na + ions are discharged and sodium metal is released. The sodium floats up and is taken into a special collection (of course, without air access). At the anode, chlorine nonions Cl - are discharged and chlorine gas is released - a valuable by-product of sodium production.

Typically, the electrolyzer operates under a load of 25 - 30 thousand A, while 400 - 500 kg of sodium and 600 - 700 kg of chlorine are produced per day.

“THE MOST METALLIC METAL.” This is sometimes called sodium. This is not entirely fair: in the periodic table, metallic properties increase as you move from right to left and from top to bottom. So the analogues of sodium in the group - francium, rubidium, cesium, potassium - have more pronounced metallic properties than sodium. (Of course, we mean only chemical properties.) But sodium also has a full range of “metallic” chemical properties. It easily donates its valence electrons (one per atom), always exhibits valency 1+, and has pronounced reducing properties. Sodium hydroxide NaOH is a strong alkali. All this is explained by the structure of the sodium atom, on the outer shell of which there is one electron, and the atom can easily part with it.

Is sodium a metal or a non-metal? It is a mistake to believe that the second option. Sodium is a soft, silvery-white metal that appears on the periodic table at atomic number 11.

Moreover, it (or rather its compounds) has been known since ancient times! Even the Bible mentions sodium as an ingredient in cleaning products. However, this is a historical note, albeit an interesting one. Now it’s worth talking about the features of this element and its other characteristics.

Physical properties

So, the answer to the question “Is sodium a metal or a non-metal?” very clear. Even just looking at this substance, you can understand everything. It is obvious that Which, by the way, although it has a silvery-white color, has a violet tint in thin layers.

This is a very plastic substance. Soft metals are those that can be forged without much effort and are also characterized by ductility and fusibility. But in relation to sodium, this word can be applied in the literal sense. It can be cut with a knife without effort. By the way, a fresh cut shines very brightly. Other properties include:

• Density. Under normal conditions - 0.971 g/cm³.
• The melting and boiling points are 97.81 °C and 882.95 °C, respectively.
• Molar heat capacity - 28.23 J/(K.mol).
• The specific heat of fusion and evaporation is 2.64 kJ/mol and 97.9 kJ/mol, respectively.
• Molar volume - 23.7 cm³/mol.

It is worth noting that under pressure, sodium (Na) turns red and transparent. In this state, this metal is very similar to ruby.

If you place it at room temperature, it forms crystals in cubic symmetry. However, by lowering it to −268 °C, you can see how the metal transforms into the hexagonal phase. To understand what we are talking about, just remember graphite. This is a prime example of a hexagonal crystal.

Oxidation and combustion

Now we can move on to the chemical properties of sodium (Na). This alkali metal, when exposed to air, easily oxidizes. As a result, sodium oxide (Na 2 O) is formed. It looks like colorless cubic crystals. This is a salt-forming binary inorganic substance that is used as a reagent in the synthesis process. It is used to make sodium hydroxide and other compounds.

Therefore, to protect the metal from oxygen exposure, it is stored in kerosene.

But during combustion, sodium peroxide (Na 2 O 2) is formed. They look like white-yellow crystals, which are characterized by vigorous interaction with water, accompanied by the release of heat. Na 2 O 2 is used for bleaching silk, wool, fabrics, straw, viscose and wood pulp.

Reactions with water

The silvery-white soft metal sodium also interacts successfully with H2O. The reaction with water is very violent. A small piece of sodium placed in this liquid floats to the surface and begins to melt due to the heat generated. As a result, it turns into a white ball, which moves quickly along the surface of the water in different directions.

This very spectacular reaction is accompanied by the release of hydrogen. When conducting such an experiment, care must be taken as it may ignite. And everything happens according to the following equation: 2Na + 2H 2 O → 2NaOH + H 2.

Interactions with nonmetals

Sodium is a metal, it can also be called a strong reducing agent, which it is. Like other alkaline substances, however. So it reacts vigorously with many nonmetals other than carbon, iodine, and noble gases, which include radioactive radon, krypton, neon, xenon, argon, and helium. Such reactions look like this: 2Na + Cl 2 → 2NaCl. Or here’s another example: 2Na + H 2 → 250-450 °C 2NaH.

It is worth noting that sodium is more active than lithium. In principle, it can react with nitrogen, but very poorly (in a glow discharge). As a result of this interaction, an unstable substance called sodium nitride is formed. These are dark gray crystals that react with water and decompose when heated. They are formed according to the equation: 6Na + N 2 → 2Na 3 N.

Reactions with acids

They should also be listed, talking about the chemical characteristics of sodium. This substance reacts with dilute acids like an ordinary metal. It looks like this: 2Na + 2HCl → 2NaCl + H2.

Sodium interacts differently with concentrated substances that are characterized by oxidative reactions; such reactions are accompanied by the release of reduction products. Here is an example of a formula: 8Na + 10NHO 3 → 8NaNO 3 + 3H 2 O.

It is also worth noting that the alkali metal sodium easily dissolves in liquid ammonia (NH 3), a 10% solution of which is well known to everyone as ammonia. The equation looks like this: Na + 4NH3 → - 40°C Na 4. As a result of this reaction, a blue solution is formed.

The metal also interacts with gaseous ammonia, but when heated. This reaction looks like this: 2Na + 2NH3 → 35 0°C 2NaNH 2 + H 2.

Other connections

When listing the main properties of sodium, it is also worth mentioning that it can interact with mercury, a unique element that under normal conditions is a white-silver heavy liquid, while being a metal.

As a result of this reaction, an alloy is formed. Its exact name is sodium amalgam. This substance is used as a reducing agent, its properties being softer than pure metal. If you heat it with potassium, you get a liquid alloy.

This metal can also dissolve in so-called crown ethers - macroheterocyclic compounds, but only in the presence of organic solvents. As a result of this reaction, an alkalide (a salt, a strong reducing agent) or an electride (a blue solvent) is formed.

It is also impossible not to mention that alkyl halides, which are halogen-carbon substances, with an excess of sodium give organosodium compounds. In air they usually ignite spontaneously. And in water they explode.

Application

The properties and characteristics of sodium allow it to be widely used in industry, metallurgy and preparative chemistry as a powerful reducing agent. In addition, this substance is involved:

• In the drying of organic solvents.
• In the production of sulfur-sodium batteries.
• In exhaust valves of truck engines. Plays the role of a liquid heat sink.
• In the manufacture of electrical wires that are designed for high currents.
• In alloys with cesium, rubidium and potassium. Together with these substances, sodium forms a highly efficient coolant, which, by the way, is used for fast neutrons in nuclear reactors.
• In gas discharge lamps.

And these are just some of the areas of its application. But the most common substance in the world is sodium chloride. It is found in almost every home, because it is table salt.

It is also impossible not to mention that the earth’s crust consists of 2.6% sodium. And in general, it is in 7th place in the ranking of the most common elements in nature and in 5th place in the list of the most common metals. It is impossible to find sodium in nature in its pure form, since it is chemically active, but it is found in huge quantities in the form of sulfate, carbonate, nitrate and chloride.

Biological role

So, all the basics on the topic “Is sodium a metal or a non-metal?” it was said. Finally, a few words about the biological role of this substance.

Sodium is an integral part of any living organism. Human is no exception. Here are his roles:

• Maintains osmotic pressure.
• Transports carbon dioxide.
• Normalizes water balance.
• Promotes the transport of glucose, amino acids, anions through cell membranes.
• Its exchange with potassium ions influences the formation of the action potential.
• Positively affects protein metabolism.
• Takes part in the hydration process.

Sodium is included in almost all products. But its main sources are salt and baking soda. Vitamin D improves the absorption of this substance.

Sodium deficiency does not occur, but problems associated with consuming insufficient amounts can occur during fasting. This is fraught with weight loss, vomiting, impaired absorption of monosaccharides, and the formation of gases in the gastrointestinal tract. In especially severe cases, neuralgia and convulsions occur. Therefore, it is better not to subject your body to severe starvation.