In the periodic table at number 1 is located the most common element in the universe - hydrogen. Its distribution, in percentage terms, approaches 75%. Its lowest content is noted in the atmospheric layers - 0.0001%. The Earth's crust contains 1% gas by weight. Its greatest amount is noted in water: 12%. On our planet, this is the third most widely used chemical element.
Item Description
A hydrogen molecule, the formula of which is H-H or H2, is endowed with physical and chemical properties.
Hydrogen is a gas that is endowed with neither color nor smell. The location of hydrogen in the table at 1 place is due to the fact that under various conditions this element can manifest itself as a metal or as a gas. On its outer orbital there is 1 electron, which hydrogen can give (metal properties) or take another (gas quality).
The diameter of the hydrogen molecule is 27 nm.
The diameter of the hydrogen atom is 1A, the radius is 0.41 A.
The properties
The physical ones include the following:
- Boiling point - 256 about C.
- Melting point -259.2 about C.
- Air mass (D) - 0.069.
- Hydrogen is poorly soluble in water.
Chemical properties are as follows:
- The nonpolar bond between the particles of the molecule has an energy of 436 kJ / mol.
- The temperature of thermal dissociation is 2000 about C.
- Reacts with:
- halogens;
- oxygen;
- gray;
- nitrogen;
- nitric oxide;
- active metals.
In nature, hydrogen is found both in its natural form and in the form of isotopes: protium, deuterium and tritium.
Molecule structure
The molecule of the element has a simple structure. The composition of the hydrogen molecule is represented by two atoms, which, drawing together, 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 on 1s orbital.
H - 1e = H + this hydrogen ion is positive.
This expression indicates that hydrogen has similar parameters with the elements of group 1 in the periodic system, which are alkaline metals (lithium, sodium, potassium), giving off their only electron on the outer orbital.
+ 1 = – hydrogen ion is negative.
This equation shows that hydrogen is related to similar elements from the 7th group, which are gas and are able to accept the missing electrons to their external electronic level. Such gases include: fluorine, chlorine, bromine, etc.
The composition of the hydrogen molecule is graphically presented below.
The distance between the hydrogen atoms is r = 0.74 A, while the sum of the orbital radii is 1.06 A. This affects the depth of overlap of the electron clouds and the strong, stable hydrogen bond.
The hydrogen atom is the most elemental atom in nature. The size of the 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: 1H.
The nuclear structure looks like a complex of proton and neutron (2H).
3H - tritium - in its atomic structure is endowed with a nucleus with 1 proton and two neutrons.
Weight
In science, there are formulas that calculate what the mass of a hydrogen molecule is. In relation to the element, the molecular and atomic masses are determined.
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 quantity.
The mass of an atom is 1.008 a.m. Therefore, 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. E. m. The mass of a hydrogen molecule is expressed in grams per mole (g / mol).
Value in nature
The most significant substance in nature, which forms hydrogen in complex with oxygen, is water. Water is the source of life, so hydrogen is a vital element.
Of the 100% of all chemical elements that make up the body’s environment, 1/10 part, or 10%, is hydrogen. In addition to water, it is able to maintain a quaternary protein structure, which is possible due to the hydrogen bond.
The principle of complementarity of nucleic acids also occurs with the action of a hydrogen molecule. In a plant cell, H takes part in the process of photosynthesis, biosynthesis, and in energy transfer through membrane channels.
Application
In the chemical industry, hydrogen is quite widely applicable. 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 approved by the food industry of the Russian Federation.
Hydrogen was once involved in the aeronautics industry, since the substance is lighter than air. So, in the 30s of the last century, this type of gas was filled with balloons and airships. Despite its low cost and ease of use, hydrogen was soon ceased to be used as a filler, since cases of aircraft explosions became more frequent.
Nowadays, gas is used as fuel used in the space industry. However, the methods of its use for the operation of engines of cars and trucks are considered, since the element does not emit harmful impurities into the atmosphere during combustion, and, therefore, is environmentally friendly.
An integral component of hydrogen isotopes act as part of many medications. Deuterium is used in pharmacological studies to determine the behavior and effects of a drug in the body. Tritium is used in radio diagnostics as an element that determines the biochemical reactions of enzyme metabolism. Hydrogen is part of peroxide, which is a disinfectant.