In the periodic table of Mendeleev at number 1 is the most common element in the universe - hydrogen. Its distribution, in percentage terms, approaches 75%. Its lowest content is noted in the layers of the atmosphere - 0.0001%. The Earth's crust contains 1% gas by mass. Its largest amount is observed in water: 12%. On our planet, it is the third most common chemical element.
Item description
The hydrogen molecule, whose formula is H-H or H2, is endowed with physical and chemical properties.
Hydrogen is a gas that has neither color nor smell. The location of hydrogen in the table in 1st place is due to the fact that under various conditions this element can manifest itself as a metal or as a gas. It has 1 electron in its outer orbital, which hydrogen can donate (metallic properties) or accept one more (gas qualities).
The diameter of a hydrogen molecule is 27 nm.
The diameter of a hydrogen atom is 1A, the radius is 0.41 A.
Properties
Physical includes the following:
- Boiling point– 256oS.
- Melting point -259.2oC.
- Air weight (D) - 0.069.
- Hydrogen is poorly soluble in water.
The chemical properties are:
- The non-polar bond between the particles of a molecule has an energy of 436 kJ/mol.
- The thermal dissociation temperature is 2000oC.
- Reacts with:
- halogens;
- oxygen;
- grey;
- nitrogen;
- nitric oxide;
- active metals.
In nature, hydrogen occurs both naturally and in the form of isotopes: protium, deuterium and tritium.
The structure of the molecule
The molecule of an element has a simple structure. The composition of the hydrogen molecule is represented by two atoms, which, approaching, form a covalent non-polar bond, as well as one electron pair. The structure of one atom is: 1 positively charged nucleus, around which 1 negatively charged electron moves. This electron is located in the 1s orbital.
H - 1e=H+ this hydrogen ion is positive.
This expression indicates that hydrogen has similar parameters to Group 1 elements in the Periodic Table, which are alkali metals (lithium, sodium, potassium) donating their only electron in the outer orbit.
H + 1e=H– negative hydrogen ion.
This equation shows that hydrogen is related to similar elements from the 7th group, which are gas and are able to accept the missing electronsto its outer electronic level. These gases include: fluorine, chlorine, bromine, etc.
The composition of the hydrogen molecule is graphically presented below.
The distance between hydrogen atoms is r=0.74 A, while the sum of the orbital radii is 1.06 A. This affects the depth of electron cloud overlap and a strong, stable hydrogen bond.
The hydrogen atom is the most elemental atom in nature. The size of an atomic proton is 10.5 A, and the diameter of one atom is 0.1 nm.
Isotope molecules have a special structure. The atomic nucleus of protium consists of only one proton. The isotope is designated: 1Н.
The nuclear structure looks like a complex of a proton and a neutron (2H).
3Н - tritium - in its atomic structure is endowed with a nucleus with 1 proton and two neutrons.
Mass
In science, there are formulas that calculate what the mass of a hydrogen molecule is. In relation to the element, determine the molecular and atomic masses.
The molar mass of a hydrogen molecule is calculated by the general formula:
M=m / n, where m is the mass of the substance, n is its amount.
The mass of an atom is 1.008 amu. Consequently, the relative mass of the molecule will also be 1.008. Since the hydrogen molecule consists of two atoms, the relative atomic weight is 2.016 a.u. m. The mass of a hydrogen molecule is expressed in grams per mole (g/mol).
Value innature
The most significant substance in nature that forms hydrogen in combination with oxygen is water. Water is the source of life, so hydrogen is a vital element.
Of 100% of all chemical elements that make up the organism's environment, 1/10 part, or 10%, is hydrogen. In addition to water, it is able to maintain a quaternary protein structure, which is made possible by hydrogen bonding.
The principle of nucleic acid complementarity also occurs with the action of the hydrogen molecule. In a plant cell, H takes part in the process of photosynthesis, biosynthesis, and in the transfer of energy through membrane channels.
Application
In the chemical industry, hydrogen is widely used. It is added in the manufacture of plastic products, in soap making, as well as in ammonia and menthol production.
Food industry: in the production of food, hydrogen is added as a food additive E949. Such a component can be seen on the packaging of margarine, vegetable oils. Additive E949 is allowed by the food industry of the Russian Federation.
Hydrogen was once also used in the aeronautics industry, since the substance is lighter than air. So, in the 30s of the last century, balloons and airships were filled with this type of gas. Despite its cheapness and ease of use, hydrogen was soon abandoned as a filler as aircraft explosions became more frequent.
Today, gas is used asfuel used in the space industry. However, methods of using it for the operation of engines of cars and trucks are being considered, since the element does not emit harmful impurities into the atmosphere during combustion, and, therefore, is environmentally friendly.
Hydrogen isotopes are an integral component of many medicines. Deuterium is used in pharmacological research to determine the behavior and effects of a drug in the body. Tritium is used in radiodiagnostics as an element that determines the biochemical reactions of enzyme metabolism. Hydrogen is part of peroxide, which is a disinfectant.
