One of the most important parameters of a substance is its density. It is simple to understand what it is: under the same volume, a higher density substance has a greater mass than a lower density substance. But what this density depends is not entirely clear. Felix Gorbatesevich, chief researcher at the Institute of Geology at Kola Science Center, analyzed the relationship between the atom parameters of various chemical elements and their density.
Results of this study published in "Israel Science - Technology Advantages and Engineering Physics". In the most general approximation, it can be said that the larger the sequence number of the chemical element in the periodic table of , the higher its density.
The main characteristic of an element is its atomic weight, that is, the average value of the mass of the isotopes containing a certain number of protons and neutrons of the element. The masses of proton and neutron are very close: they are 1.6723x10-27 kg and 1.6746x10-27 kg, respectively. The mass of an electron must be more than three orders of magnitude smaller: 9.108x10-31 kg.
Even for heavy elements (e.g., lead has 82 electrons in one atom), their impact on atomic weight is extremely trivial, and the atomic weight ultimately depends on the total mass of protons and neutrons in atomic nucleus . However, the number, size and shape of electrons in the shell determine the forces that atoms repel each other, so the atomic mass of an element has no direct relationship with its density.
Dependence of inert gas density on the sum of protons and neutrons in its nucleus
But in chemical elements, there is a set of protons, neutrons and electrons that increase proportionally. This is a group of inert gases: helium, neon, argon, krypton, xenon, radon. The short-lived element oganesson, created by artificially, belongs to the same group. Their structure is as follows: in each shell, except for helium (this element has one shell that contains two electrons), it contains eight electrons, and the remaining electron shell has a roughly similar structure.
Due to the strong electric field generated by external electrons, the inert gas atoms have great mutual repulsion, so even xenon and radon with heavy nuclei remain gaseous at atmospheric pressure and room temperature.
Scientists compared the density value of each inert gas with the sum of protons and neutrons in the nucleus and found that under the reliability of R2 = 0.9998, there is a proportional relationship between the number of protons and neutrons in the nucleus. The density of the core and gas of the isotope isotope. He tried to extend this method to matter composed of other atoms, so that the connection between density, the outer volume of the atom and the total number of protons and neutrons in the nucleus can be found.
The main part of the periodic table of elements consists of metal and semi-metal. Their atomic weight and density have been measured repeatedly and are given in numerous publications. The researchers analyzed the relationship between atomic weight (A), density (ρ), atomic diameter (Da) and nuclear diameter (Dn). Considering that the shape of the metal atom is close to the sphere, he calculated the ratio of the atomic volume of each element to the volume of its nucleus (Vn/Va), which is equal to the cubic cube of the diameter. atoms and nuclei ((Dn)3 /(Da)3), and reveals a fairly clear relationship between this ratio and the density of matter. It is described by the equation ρ = 1.32х(Vn/Va)х10 exp14, g/cm3, and the linear correlation coefficient R2 = 0.958. This strict dependency of
shows that the density of matter depends directly on the mass of the atomic nucleus and the volume occupied by the extreme electron shell of the atom in space, and indicates the dense accumulation of metal atoms. The deviation from this dependence is observed in the semi-metals and elements located in the spacer between metal and non-metals. They may be caused by an atomic shape or a weakening of force between atoms. The analysis conducted by
generally confirms the conclusion that the shapes of the atoms and nuclei of many elements are close to spherical shapes, and establishes a causal relationship between the density, mass and atomic size of the nucleus. It opens up the possibility of estimating the density of more complex matter composed of atoms of different elements.
