Chemical properties of hydrogen. The importance of hydrogen in nature

It has its own specific position in the periodic table, which reflects the properties it exhibits and speaks about its electronic structure. However, among all of them there is one special atom that occupies two cells at once. It is located in two groups of elements that are completely opposite in their properties. This is hydrogen. Such features make it unique.

Hydrogen is not just an element, but also a simple substance, as well as an integral part of many complex compounds, a biogenic and organogenic element. Therefore, let us consider its characteristics and properties in more detail.

Hydrogen as a chemical element

Hydrogen is an element of the first group of the main subgroup, as well as the seventh group of the main subgroup in the first minor period. This period consists of only two atoms: helium and the element we are considering. Let us describe the main features of the position of hydrogen in the periodic table.

The atomic number of hydrogen is 1, the number of electrons is the same, and, accordingly, the number of protons is the same. Atomic mass - 1.00795. There are three isotopes of this element with mass numbers 1, 2, 3. However, the properties of each of them are very different, since an increase in mass even by one for hydrogen is immediately double.
The fact that it contains only one electron on its outer surface allows it to successfully exhibit both oxidizing and reducing properties. In addition, after donating an electron, it remains in a free orbital, which takes part in the formation of chemical bonds according to the donor-acceptor mechanism.
Hydrogen is a strong reducing agent. Therefore, its main place is considered to be the first group of the main subgroup, where it heads the most active metals - alkali.
However, when interacting with strong reducing agents, such as metals, it can also be an oxidizing agent, accepting an electron. These compounds are called hydrides. According to this feature, it heads the subgroup of halogens with which it is similar.
Due to its very small atomic mass, hydrogen is considered the lightest element. In addition, its density is also very low, so it is also a benchmark for lightness.

Thus, it is obvious that the hydrogen atom is a completely unique element, unlike all others. Consequently, its properties are also special, and the simple and complex substances formed are very important. Let's consider them further.

Simple substance

If we talk about this element as a molecule, then we must say that it is diatomic. That is, hydrogen (a simple substance) is a gas. Its empirical formula will be written as H2, and its graphical formula will be written through the single sigma H-H relationship. The mechanism of bond formation between atoms is covalent nonpolar.

Steam methane reforming.
Coal gasification - the process involves heating coal to 1000 0 C, resulting in the formation of hydrogen and high-carbon coal.
Electrolysis. This method can only be used for aqueous solutions of various salts, since the melts do not lead to a discharge of water at the cathode.

Laboratory methods for producing hydrogen:

Hydrolysis of metal hydrides.
The effect of dilute acids on active metals and medium activity.
Interaction of alkali and alkaline earth metals with water.

To collect the hydrogen produced, you must hold the test tube upside down. After all, this gas cannot be collected in the same way as, for example, carbon dioxide. This is hydrogen, it is much lighter than air. It evaporates quickly, and in large quantities it explodes when mixed with air. Therefore, the test tube should be inverted. After filling it, it must be closed with a rubber stopper.

To check the purity of the collected hydrogen, you should bring a lit match to the neck. If the clap is dull and quiet, it means the gas is clean, with minimal air impurities. If it is loud and whistling, it is dirty, with a large proportion of foreign components.

Areas of use

When hydrogen is burned, such a large amount of energy (heat) is released that this gas is considered the most profitable fuel. Moreover, it is environmentally friendly. However, to date its application in this area is limited. This is due to ill-conceived and unsolved problems of synthesizing pure hydrogen, which would be suitable for use as fuel in reactors, engines and portable devices, as well as residential heating boilers.

After all, the methods for producing this gas are quite expensive, so first it is necessary to develop a special synthesis method. One that will allow you to obtain the product in large volumes and at minimal cost.

There are several main areas in which the gas we are considering is used.

Chemical syntheses. Hydrogenation is used to produce soaps, margarines, and plastics. With the participation of hydrogen, methanol and ammonia, as well as other compounds, are synthesized.
In the food industry - as additive E949.
Aviation industry (rocket science, aircraft manufacturing).
Electric power industry.
Meteorology.
Environmentally friendly fuel.

Obviously, hydrogen is as important as it is abundant in nature. The various compounds it forms play an even greater role.

Hydrogen compounds

These are complex substances containing hydrogen atoms. There are several main types of such substances.

Hydrogen halides. The general formula is HHal. Of particular importance among them is hydrogen chloride. It is a gas that dissolves in water to form a solution of hydrochloric acid. This acid is widely used in almost all chemical syntheses. Moreover, both organic and inorganic. Hydrogen chloride is a compound with the empirical formula HCL and is one of the largest produced in our country annually. Hydrogen halides also include hydrogen iodide, hydrogen fluoride and hydrogen bromide. They all form the corresponding acids.
Volatile Almost all of them are quite poisonous gases. For example, hydrogen sulfide, methane, silane, phosphine and others. At the same time, they are very flammable.
Hydrides are compounds with metals. They belong to the class of salts.
Hydroxides: bases, acids and amphoteric compounds. They necessarily contain hydrogen atoms, one or more. Example: NaOH, K 2, H 2 SO 4 and others.
Hydrogen hydroxide. This compound is better known as water. Another name is hydrogen oxide. The empirical formula looks like this - H 2 O.
Hydrogen peroxide. This is a strong oxidizing agent, the formula of which is H 2 O 2.
Numerous organic compounds: hydrocarbons, proteins, fats, lipids, vitamins, hormones, essential oils and others.

It is obvious that the variety of compounds of the element we are considering is very large. This once again confirms its high importance for nature and humans, as well as for all living beings.

- this is the best solvent

As mentioned above, the common name for this substance is water. Consists of two hydrogen atoms and one oxygen, connected by covalent polar bonds. The water molecule is a dipole, this explains many of the properties it exhibits. In particular, it is a universal solvent.

It is in the aquatic environment that almost all chemical processes occur. Internal reactions of plastic and energy metabolism in living organisms are also carried out using hydrogen oxide.

Water is rightfully considered the most important substance on the planet. It is known that no living organism can live without it. On Earth it can exist in three states of aggregation:

liquid;
gas (steam);
solid (ice).

Depending on the hydrogen isotope included in the molecule, three types of water are distinguished.

Light or protium. An isotope with mass number 1. Formula - H 2 O. This is the usual form that all organisms use.
Deuterium or heavy, its formula is D 2 O. Contains the isotope 2 H.
Super heavy or tritium. The formula looks like T 3 O, isotope - 3 H.

The reserves of fresh protium water on the planet are very important. There is already a shortage of it in many countries. Methods are being developed for treating salt water to produce drinking water.

Hydrogen peroxide is a universal remedy

This compound, as mentioned above, is an excellent oxidizing agent. However, with strong representatives he can also behave as a restorer. In addition, it has a pronounced bactericidal effect.

Another name for this compound is peroxide. It is in this form that it is used in medicine. A 3% solution of crystalline hydrate of the compound in question is a medical medicine that is used to treat small wounds for the purpose of disinfecting them. However, it has been proven that this increases the healing time of the wound.

Hydrogen peroxide is also used in rocket fuel, in industry for disinfection and bleaching, and as a foaming agent for the production of appropriate materials (foam, for example). Additionally, peroxide helps clean aquariums, bleach hair, and whiten teeth. However, it causes harm to tissues, so it is not recommended by specialists for these purposes.

Designation - H (Hydrogen);
Latin name - Hydrogenium;
Period - I;
Group - 1 (Ia);
Atomic mass - 1.00794;
Atomic number - 1;
Atomic radius = 53 pm;
Covalent radius = 32 pm;
Electron distribution - 1s 1;
melting temperature = -259.14°C;
boiling point = -252.87°C;
Electronegativity (according to Pauling/according to Alpred and Rochow) = 2.02/-;
Oxidation state: +1; 0; -1;
Density (no.) = 0.0000899 g/cm 3 ;
Molar volume = 14.1 cm 3 /mol.

Binary compounds of hydrogen with oxygen:

Hydrogen (“giving birth to water”) was discovered by the English scientist G. Cavendish in 1766. It is the simplest element in nature - a hydrogen atom has a nucleus and one electron, which is probably why hydrogen is the most abundant element in the Universe (accounting for more than half the mass of most stars).

About hydrogen we can say that “the spool is small, but expensive.” Despite its “simplicity,” hydrogen provides energy to all living beings on Earth - a continuous thermonuclear reaction takes place on the Sun during which one helium atom is formed from four hydrogen atoms, this process is accompanied by the release of a colossal amount of energy (for more details, see Nuclear fusion).

In the earth's crust, the mass fraction of hydrogen is only 0.15%. Meanwhile, the overwhelming majority (95%) of all chemical substances known on Earth contain one or more hydrogen atoms.

In compounds with non-metals (HCl, H 2 O, CH 4 ...), hydrogen gives up its only electron to more electronegative elements, exhibiting an oxidation state of +1 (more often), forming only covalent bonds (see Covalent bond).

In compounds with metals (NaH, CaH 2 ...), hydrogen, on the contrary, accepts another electron into its only s-orbital, thus trying to complete its electronic layer, exhibiting an oxidation state of -1 (less often), often forming an ionic bond (see Ionic bond), because the difference in electronegativity of the hydrogen atom and the metal atom can be quite large.

H 2

In the gaseous state, hydrogen exists in the form of diatomic molecules, forming a nonpolar covalent bond.

Hydrogen molecules have:

great mobility;
great strength;
low polarizability;
small size and weight.

Properties of hydrogen gas:

the lightest gas in nature, colorless and odorless;
poorly soluble in water and organic solvents;
dissolves in small amounts in liquid and solid metals (especially platinum and palladium);
difficult to liquefy (due to its low polarizability);
has the highest thermal conductivity of all known gases;
when heated, it reacts with many non-metals, exhibiting the properties of a reducing agent;
at room temperature it reacts with fluorine (an explosion occurs): H 2 + F 2 = 2HF;
reacts with metals to form hydrides, exhibiting oxidizing properties: H 2 + Ca = CaH 2 ;

In compounds, hydrogen exhibits its reducing properties much more strongly than its oxidizing properties. Hydrogen is the most powerful reducing agent after coal, aluminum and calcium. The reducing properties of hydrogen are widely used in industry to obtain metals and nonmetals (simple substances) from oxides and gallides.

Fe 2 O 3 + 3H 2 = 2Fe + 3H 2 O

Reactions of hydrogen with simple substances

Hydrogen accepts an electron, playing a role reducing agent, in reactions:

With oxygen(when ignited or in the presence of a catalyst), in a ratio of 2:1 (hydrogen:oxygen) an explosive detonating gas is formed: 2H 2 0 +O 2 = 2H 2 +1 O+572 kJ
With gray(when heated to 150°C-300°C): H 2 0 +S ↔ H 2 +1 S
With chlorine(when ignited or irradiated with UV rays): H 2 0 +Cl 2 = 2H +1 Cl
With fluorine: H 2 0 +F 2 = 2H +1 F
With nitrogen(when heated in the presence of catalysts or at high pressure): 3H 2 0 +N 2 ↔ 2NH 3 +1

Hydrogen donates an electron, playing a role oxidizing agent, in reactions with alkaline And alkaline earth metals with the formation of metal hydrides - salt-like ionic compounds containing hydride ions H - these are unstable white crystalline substances.

Ca+H 2 = CaH 2 -1 2Na+H 2 0 = 2NaH -1

It is not typical for hydrogen to exhibit an oxidation state of -1. When reacting with water, the hydrides decompose, reducing water to hydrogen. The reaction of calcium hydride with water is as follows:

CaH 2 -1 +2H 2 +1 0 = 2H 2 0 +Ca(OH) 2

Reactions of hydrogen with complex substances

at high temperatures, hydrogen reduces many metal oxides: ZnO+H 2 = Zn+H 2 O
methyl alcohol is obtained by the reaction of hydrogen with carbon monoxide (II): 2H 2 +CO → CH 3 OH
In hydrogenation reactions, hydrogen reacts with many organic substances.

The equations of chemical reactions of hydrogen and its compounds are discussed in more detail on the page “Hydrogen and its compounds - equations of chemical reactions involving hydrogen.”

Applications of hydrogen

in nuclear energy, hydrogen isotopes are used - deuterium and tritium;
in the chemical industry, hydrogen is used for the synthesis of many organic substances, ammonia, hydrogen chloride;
in the food industry, hydrogen is used in the production of solid fats through the hydrogenation of vegetable oils;
for welding and cutting metals, the high combustion temperature of hydrogen in oxygen (2600°C) is used;
in the production of some metals, hydrogen is used as a reducing agent (see above);
since hydrogen is a light gas, it is used in aeronautics as a filler for balloons, aerostats, and airships;
Hydrogen is used as a fuel mixed with CO.

Recently, scientists have been paying a lot of attention to the search for alternative sources of renewable energy. One of the promising areas is “hydrogen” energy, in which hydrogen is used as fuel, the combustion product of which is ordinary water.

Methods for producing hydrogen

Industrial methods for producing hydrogen:

methane conversion (catalytic reduction of water vapor) with water vapor at high temperature (800°C) on a nickel catalyst: CH 4 + 2H 2 O = 4H 2 + CO 2 ;
conversion of carbon monoxide with water vapor (t=500°C) on a Fe 2 O 3 catalyst: CO + H 2 O = CO 2 + H 2 ;
thermal decomposition of methane: CH 4 = C + 2H 2;
gasification of solid fuels (t=1000°C): C + H 2 O = CO + H 2 ;
electrolysis of water (a very expensive method that produces very pure hydrogen): 2H 2 O → 2H 2 + O 2.

Laboratory methods for producing hydrogen:

action on metals (usually zinc) with hydrochloric or dilute sulfuric acid: Zn + 2HCl = ZCl 2 + H 2 ; Zn + H 2 SO 4 = ZnSO 4 + H 2;
interaction of water vapor with hot iron filings: 4H 2 O + 3Fe = Fe 3 O 4 + 4H 2.

When starting to consider the chemical and physical properties of hydrogen, it should be noted that in its usual state, this chemical element is in gaseous form. Colorless hydrogen gas is odorless and tasteless. For the first time, this chemical element was named hydrogen after the scientist A. Lavoisier conducted experiments with water, as a result of which world science learned that water is a multicomponent liquid that contains Hydrogen. This event occurred in 1787, but long before this date, hydrogen was known to scientists under the name “flammable gas.”

Hydrogen in nature

According to scientists, hydrogen is contained in the earth's crust and in water (approximately 11.2% of the total volume of water). This gas is part of many minerals that humanity has been extracting from the bowels of the earth for centuries. Some of the properties of hydrogen are characteristic of oil, natural gases and clay, and of animal and plant organisms. But in its pure form, that is, not combined with other chemical elements of the periodic table, this gas is extremely rare in nature. This gas can come to the surface of the earth during volcanic eruptions. Free hydrogen is present in the atmosphere in negligible quantities.

Chemical properties of hydrogen

Since the chemical properties of hydrogen are heterogeneous, this chemical element belongs to both group I of the Mendeleev system and group VII of the system. As a member of the first group, hydrogen is essentially an alkali metal that has an oxidation state of +1 in most of the compounds in which it is found. The same valency is characteristic of sodium and other alkali metals. Due to these chemical properties, hydrogen is considered an element similar to these metals.

If we are talking about metal hydrides, then the hydrogen ion has a negative valency - its oxidation state is -1. Na+H- is built according to the same scheme as Na+Cl- chloride. This fact is the reason to assign hydrogen to group VII of the periodic system. Hydrogen, being in the state of a molecule, provided that it is in an ordinary environment, is inactive, and can only combine with non-metals that are more active for it. These metals include fluorine; in the presence of light, hydrogen combines with chlorine. If hydrogen is heated, it becomes more active, reacting with many elements of the periodic table of Mendeleev.

Atomic hydrogen exhibits more active chemical properties than molecular hydrogen. Oxygen molecules form water - H2 + 1/2O2 = H2O. When hydrogen interacts with halogens, hydrogen halides H2 + Cl2 = 2HCl are formed, and hydrogen enters into this reaction in the absence of light and at fairly high negative temperatures - up to - 252°C. The chemical properties of hydrogen make it possible to use it for the reduction of many metals, since when it reacts, hydrogen absorbs oxygen from metal oxides, for example, CuO + H2 = Cu + H2O. Hydrogen participates in the formation of ammonia by interacting with nitrogen in the reaction ZH2 + N2 = 2NH3, but provided that a catalyst is used and the temperature and pressure are increased.

A vigorous reaction occurs when hydrogen reacts with sulfur in the reaction H2 + S = H2S, which results in hydrogen sulfide. The interaction of hydrogen with tellurium and selenium is slightly less active. If there is no catalyst, then it reacts with pure carbon, hydrogen only under the condition that high temperatures are created. 2H2 + C (amorphous) = CH4 (methane). During the activity of hydrogen with some alkali and other metals, hydrides are obtained, for example, H2 + 2Li = 2LiH.

Physical properties of hydrogen

Hydrogen is a very light chemical. At least, scientists say that at the moment, there is no lighter substance than hydrogen. Its mass is 14.4 times lighter than air, its density is 0.0899 g/l at 0°C. At temperatures of -259.1°C, hydrogen is capable of melting - this is a very critical temperature, which is not typical for the transformation of most chemical compounds from one state to another. Only an element such as helium exceeds the physical properties of hydrogen in this regard. The liquefaction of hydrogen is difficult, since its critical temperature is (-240°C). Hydrogen is the most heat-conducting gas known to mankind. All the properties described above are the most significant physical properties of hydrogen that are used by humans for specific purposes. Also, these properties are the most relevant for modern science.

Hydrogen was discovered in the second half of the 18th century by the English scientist in the field of physics and chemistry G. Cavendish. He managed to isolate the substance in its pure state, began studying it and described its properties.

This is the story of the discovery of hydrogen. During the experiments, the researcher determined that it is a flammable gas, the combustion of which in the air produces water. This led to the determination of the qualitative composition of water.

What is hydrogen

The French chemist A. Lavoisier first announced hydrogen as a simple substance in 1784, since he determined that its molecule contains atoms of the same type.

The name of the chemical element in Latin sounds like hydrogenium (read “hydrogenium”), which means “water-giving.” The name refers to the combustion reaction that produces water.

Characteristics of hydrogen

Designation of hydrogen N. Mendeleev assigned the first atomic number to this chemical element, placing it in the main subgroup of the first group and the first period and conditionally in the main subgroup of the seventh group.

The atomic weight (atomic mass) of hydrogen is 1.00797. The molecular weight of H2 is 2 a. e. The molar mass is numerically equal to it.

It is represented by three isotopes that have a special name: the most common protium (H), heavy deuterium (D), radioactive tritium (T).

It is the first element that can be completely separated into isotopes in a simple manner. It is based on the high difference in mass of isotopes. The process was first carried out in 1933. This is explained by the fact that only in 1932 an isotope with mass 2 was discovered.

Physical properties

Under normal conditions, the simple substance hydrogen in the form of diatomic molecules is a gas, colorless, tasteless and odorless. Slightly soluble in water and other solvents.

Crystallization temperature - 259.2 o C, boiling point - 252.8 o C. The diameter of hydrogen molecules is so small that they have the ability to slowly diffuse through a number of materials (rubber, glass, metals). This property is used when it is necessary to purify hydrogen from gaseous impurities. When n. u. hydrogen has a density of 0.09 kg/m3.

Is it possible to transform hydrogen into a metal by analogy with the elements located in the first group? Scientists have found that hydrogen, under conditions when the pressure approaches 2 million atmospheres, begins to absorb infrared rays, which indicates the polarization of the molecules of the substance. Perhaps, at even higher pressures, hydrogen will become a metal.

This is interesting: there is an assumption that on the giant planets, Jupiter and Saturn, hydrogen is found in the form of a metal. It is assumed that metallic solid hydrogen is also present in the earth's core, due to the ultra-high pressure created by the earth's mantle.

Chemical properties

Both simple and complex substances enter into chemical interaction with hydrogen. But the low activity of hydrogen needs to be increased by creating appropriate conditions - increasing the temperature, using catalysts, etc.

When heated, simple substances such as oxygen (O 2), chlorine (Cl 2), nitrogen (N 2), sulfur (S) react with hydrogen.

If you ignite pure hydrogen at the end of a gas outlet tube in air, it will burn evenly, but barely noticeably. If you place the gas outlet tube in an atmosphere of pure oxygen, then combustion will continue with the formation of water droplets on the walls of the vessel, as a result of the reaction:

The combustion of water is accompanied by the release of a large amount of heat. This is an exothermic compound reaction in which hydrogen is oxidized by oxygen to form the oxide H 2 O. It is also a redox reaction in which hydrogen is oxidized and oxygen is reduced.

The reaction with Cl 2 occurs similarly to form hydrogen chloride.

The interaction of nitrogen with hydrogen requires high temperature and high pressure, as well as the presence of a catalyst. The result is ammonia.

As a result of the reaction with sulfur, hydrogen sulfide is formed, the recognition of which is facilitated by the characteristic smell of rotten eggs.

The oxidation state of hydrogen in these reactions is +1, and in the hydrides described below – 1.

When reacting with some metals, hydrides are formed, for example, sodium hydride - NaH. Some of these complex compounds are used as fuel for rockets, as well as in thermonuclear power.

Hydrogen also reacts with substances from the complex category. For example, with copper (II) oxide, formula CuO. To carry out the reaction, copper hydrogen is passed over heated powdered copper (II) oxide. During the interaction, the reagent changes its color and becomes red-brown, and droplets of water settle on the cold walls of the test tube.

Hydrogen is oxidized during the reaction, forming water, and copper is reduced from oxide to a simple substance (Cu).

Applications

Hydrogen is of great importance for humans and is used in a variety of fields:

In chemical production it is raw materials, in other industries it is fuel. Petrochemical and oil refining enterprises cannot do without hydrogen.
In the electric power industry, this simple substance acts as a cooling agent.
In ferrous and non-ferrous metallurgy, hydrogen plays the role of a reducing agent.
This helps create an inert environment when packaging products.
Pharmaceutical industry - uses hydrogen as a reagent in the production of hydrogen peroxide.
Weather balloons are filled with this light gas.
This element is also known as a fuel reducer for rocket engines.

Scientists unanimously predict that hydrogen fuel will take the lead in the energy sector.

Receipt in industry

In industry, hydrogen is produced by electrolysis, which is subjected to chlorides or hydroxides of alkali metals dissolved in water. It is also possible to obtain hydrogen directly from water using this method.

The conversion of coke or methane with water vapor is used for these purposes. The decomposition of methane at elevated temperatures also produces hydrogen. Liquefaction of coke oven gas by fractional method is also used for the industrial production of hydrogen.

Obtained in the laboratory

In the laboratory, a Kipp apparatus is used to produce hydrogen.

The reagents are hydrochloric or sulfuric acid and zinc. The reaction produces hydrogen.

Finding hydrogen in nature

Hydrogen is more common than any other element in the Universe. The bulk of stars, including the Sun, and other cosmic bodies is hydrogen.

In the earth's crust it is only 0.15%. It is present in many minerals, in all organic substances, as well as in water, which covers 3/4 of the surface of our planet.

Traces of pure hydrogen can be found in the upper atmosphere. It is also found in a number of flammable natural gases.

Gaseous hydrogen is the least dense, and liquid hydrogen is the densest substance on our planet. With the help of hydrogen, you can change the timbre of your voice if you inhale it and speak as you exhale.

The most powerful hydrogen bomb is based on the splitting of the lightest atom.

Hydrogen H is a chemical element, one of the most common in our Universe. The mass of hydrogen as an element in the composition of substances is 75% of the total content of atoms of other types. It is part of the most important and vital compound on the planet - water. A distinctive feature of hydrogen is also that it is the first element in D.I. Mendeleev’s periodic system of chemical elements.

Discovery and exploration

The first mention of hydrogen in the writings of Paracelsus dates back to the sixteenth century. But its isolation from the gas mixture of air and the study of flammable properties were carried out already in the seventeenth century by the scientist Lemery. Hydrogen was thoroughly studied by an English chemist, physicist and natural scientist who experimentally proved that the mass of hydrogen is the smallest in comparison with other gases. In subsequent stages of the development of science, many scientists worked with him, in particular Lavoisier, who called him “the birther of water.”

Characteristics by position in PSHE

The element that opens the periodic table of D.I. Mendeleev is hydrogen. The physical and chemical properties of the atom show a certain duality, since hydrogen is simultaneously classified as belonging to the first group, the main subgroup, if it behaves like a metal and gives up a single electron in the process of a chemical reaction, and to the seventh - in the case of complete filling of the valence shell, that is, acceptance negative particle, which characterizes it as similar to halogens.

Features of the electronic structure of the element

The properties of the complex substances in which it is included, and of the simplest substance H2, are primarily determined by the electronic configuration of hydrogen. The particle has one electron with Z= (-1), which rotates in its orbit around a nucleus containing one proton with unit mass and a positive charge (+1). Its electronic configuration is written as 1s 1, which means the presence of one negative particle in the very first and only s-orbital for hydrogen.

When an electron is removed or given up, and an atom of this element has such a property that it is related to metals, a cation is obtained. In essence, the hydrogen ion is a positive elementary particle. Therefore, hydrogen deprived of an electron is simply called a proton.

Physical properties

To describe hydrogen briefly, it is a colorless, slightly soluble gas with a relative atomic mass of 2, 14.5 times lighter than air, with a liquefaction temperature of -252.8 degrees Celsius.

From experience you can easily verify that H 2 is the lightest. To do this, it is enough to fill three balls with various substances - hydrogen, carbon dioxide, ordinary air - and simultaneously release them from your hand. The one filled with CO 2 will reach the ground the fastest, after it the one inflated with the air mixture will descend, and the one containing H 2 will rise to the ceiling.

The small mass and size of hydrogen particles justify its ability to penetrate various substances. Using the example of the same ball, it is easy to verify this; after a couple of days it will deflate on its own, since the gas will simply pass through the rubber. Hydrogen can also accumulate in the structure of some metals (palladium or platinum), and evaporate from it when the temperature rises.

The property of low solubility of hydrogen is used in laboratory practice to isolate it by displacing hydrogen (the table shown below contains the main parameters) to determine the scope of its application and methods of production.

Parameter of an atom or molecule of a simple substance	Meaning
Atomic mass (molar mass)	1.008 g/mol
Electronic configuration	1s 1
Crystal lattice	Hexagonal
Thermal conductivity	(300 K) 0.1815 W/(m K)
Density at n. u.	0.08987 g/l
Boiling point	-252.76 °C
Specific heat of combustion	120.9 10 6 J/kg
Melting point	-259.2 °C
Solubility in water	18.8 ml/l

Isotopic composition

Like many other representatives of the periodic system of chemical elements, hydrogen has several natural isotopes, that is, atoms with the same number of protons in the nucleus, but a different number of neutrons - particles with zero charge and unit mass. Examples of atoms with a similar property are oxygen, carbon, chlorine, bromine and others, including radioactive ones.

The physical properties of hydrogen 1H, the most common of the representatives of this group, differ significantly from the same characteristics of its counterparts. In particular, the characteristics of the substances they contain differ. Thus, there is ordinary and deuterated water, which contains, instead of a hydrogen atom with a single proton, deuterium 2 H - its isotope with two elementary particles: positive and uncharged. This isotope is twice as heavy as ordinary hydrogen, which explains the dramatic difference in the properties of the compounds they make up. In nature, deuterium is found 3200 times less frequently than hydrogen. The third representative is tritium 3H; it has two neutrons and one proton in its nucleus.

Methods of production and isolation

Laboratory and industrial methods are quite different. Thus, gas is produced in small quantities mainly through reactions involving mineral substances, while large-scale production uses organic synthesis to a greater extent.

The following chemical interactions are used in the laboratory:

For industrial purposes, gas is produced by the following methods:

Thermal decomposition of methane in the presence of a catalyst to its constituent simple substances (the value of such an indicator as temperature reaches 350 degrees) - hydrogen H2 and carbon C.
Passing steamy water through coke at 1000 degrees Celsius to form carbon dioxide CO 2 and H 2 (the most common method).
Conversion of methane gas on a nickel catalyst at temperatures reaching 800 degrees.
Hydrogen is a by-product from the electrolysis of aqueous solutions of potassium or sodium chlorides.

Chemical interactions: general provisions

The physical properties of hydrogen largely explain its behavior in reaction processes with a particular compound. The valency of hydrogen is 1, since it is located in the first group in the periodic table, and the degree of oxidation varies. In all compounds, except hydrides, hydrogen in d.o. = (1+), in molecules of the type CN, CN 2, CN 3 - (1-).

The hydrogen gas molecule, formed by creating a generalized electron pair, consists of two atoms and is quite stable energetically, which is why under normal conditions it is somewhat inert and reacts when normal conditions change. Depending on the degree of oxidation of hydrogen in the composition of other substances, it can act as both an oxidizing agent and a reducing agent.

Substances with which hydrogen reacts and forms

Elemental interactions to form complex substances (often at elevated temperatures):

Alkali and alkaline earth metal + hydrogen = hydride.
Halogen + H 2 = hydrogen halide.
Sulfur + hydrogen = hydrogen sulfide.
Oxygen + H 2 = water.
Carbon + hydrogen = methane.
Nitrogen + H 2 = ammonia.

Interaction with complex substances:

Production of synthesis gas from carbon monoxide and hydrogen.
Reduction of metals from their oxides using H 2.
Hydrogen saturation of unsaturated aliphatic hydrocarbons.

Hydrogen bond

The physical properties of hydrogen are such that they allow it, when in combination with an electronegative element, to form a special type of bond with the same atom from neighboring molecules that have lone electron pairs (for example, oxygen, nitrogen and fluorine). The clearest example in which it is better to consider this phenomenon is water. It can be said to be stitched with hydrogen bonds, which are weaker than covalent or ionic ones, but due to the fact that there are many of them, they have a significant impact on the properties of the substance. Essentially, hydrogen bonding is an electrostatic interaction that binds water molecules into dimers and polymers, giving rise to its high boiling point.

Hydrogen in mineral compounds

All contain a proton - a cation of an atom such as hydrogen. A substance whose acidic residue has an oxidation state greater than (-1) is called a polybasic compound. It contains several hydrogen atoms, which makes dissociation in aqueous solutions multi-stage. Each subsequent proton becomes more and more difficult to remove from the acid residue. The quantitative content of hydrogen in the medium determines its acidity.

Application in human activities

Cylinders with the substance, as well as containers with other liquefied gases, such as oxygen, have a specific appearance. They are painted dark green with the word “Hydrogen” written in bright red. Gas is pumped into a cylinder under a pressure of about 150 atmospheres. The physical properties of hydrogen, in particular the lightness of the gaseous state of aggregation, are used to fill balloons, balloons, etc. with it mixed with helium.

Hydrogen, the physical and chemical properties of which people learned to use many years ago, is currently used in many industries. The bulk of it goes to the production of ammonia. Hydrogen also participates in (hafnium, germanium, gallium, silicon, molybdenum, tungsten, zirconium and others) oxides, acting in the reaction as a reducing agent, hydrocyanic and hydrochloric acids, as well as artificial liquid fuel. The food industry uses it to convert vegetable oils into solid fats.

The chemical properties and use of hydrogen in various processes of hydrogenation and hydrogenation of fats, coals, hydrocarbons, oils and fuel oil were determined. It is used to produce precious stones, incandescent lamps, and forge and weld metal products under the influence of an oxygen-hydrogen flame.