most significant achievements of the past physicists working in the field of the structure of matter at the level of electron-nuclear views, refer to the beginning of the last century.One of these breakthroughs in the knowledge of the microworld is known in the history of science called "Pauli principle » .By the time it became clear that the quantum nature of phenomena occurring within the atom, dramatically changing many concepts about the realities of the microcosm.And what it is - a quantum?This kind of physical quantity measurement unit as its minimum "serving" less that can not be.For example, the first electron orbit radius can not be smaller than 5.29 · 10-11 m. Distances less than this value correctly speaking - they would not exist.
Quantum are familiar physical concepts, which are the mass, force, energy, expands the idea of the nature of electrons and other particles that make up an atom.And, of course, subject to talk about the "building blocks of the universe," tools have been created to describe them.Since then, the state of the electron is characterized by four numbers, called quantum.Various combinations of these numbers only identify complete and unique look every electron.Once it was possible to describe the energy, space and the internal state of the electron, on the agenda got the following question - and how the electrons which each atom can be many, are located around the nucleus?How are they "pack"?The study of this issue has led to the formulation of the law, now known as the Pauli exclusion principle.What is its essence?
A little self
1. An atom in its simplest form is the main component - the nucleus and the electrons are located, respectively, in the center and in orbits around the nucleus.Orbital radius (denoted by n) take integer values beginning with one quantum - the minimum possible "portions" of the distance.For the case of n = 1, we have the lowest "low" orbit, at which the electron spins with the lowest energy.The energy level of the electron is determined by the quantum number n, which is still called the principal.Note that for a given radius of n can compute the number of electrons on the orbit of the formula N = 2 (n • n).Hence it is easy to limit the number of electrons is calculated for every orbit number n: on the first - two in the second - eight, on the third - eighteen, etc.This conclusion of the filling of the shells in an amount of electrons not exceeding N, - is an essential point that contains the Pauli exclusion principle.
2. An electron can have energy sublevels of each main level.They are denoted by l, called side (or orbital) quantum number and can have a value of l from 0 to 4. The value of l determines the spatial shape of the electron cloud: spherical, dumbbell, etc.
3. The movement of the electron, in other words, the current flow leads to the creation of a circular magnetic field.But in this case, the electron has an orbital magnetic moment, which is characterized by yet another, the third, the quantum number ml.It is called the magnetic quantum number is the projection of the orbital angular momentum of the electron in the magnetic field direction.The values that can take the number of ml, range from -l to + l, based on the zero value, and all of them can be (2l + 1).
4. Finally, the last characteristic of quantum electron - spin.It comprises only two feature ms = + 1/2 ms = -1 / 2.The physical essence of spin - is the time the mechanical momentum of the electron, which has no connection with its motion in space.
Communication Pauli principle and the periodic system of DIMendeleev
in 1925 in physics discovery was made of the fundamental properties of the microcosm, comparable in significance only with the Mendeleyev table.It received the name of his "godfather" and since then known as the Pauli exclusion principle.Chemistry, as the science of materials and their interactions within the framework of the periodic system could not explain many of the mechanisms of processes taking place at association of atoms, molecules, etc. EducationThe main reason was that the level of detail of the atom, in terms of chemistry, started on the concepts of atom, electron, nucleus.These atomic-molecular concepts emerged and established themselves around 150 years ago - in the nineteenth century.Later AMButlerov developed the theory of chemical compounds, and then opened the periodic law.It is allowed to present the birth of atoms and molecules gave understanding of the atomic device "economy".
Understanding of the characteristics of the quantum electron model was made possible after the Pauli principle was formulated.With it received an explanation of the picture location and the order of their shells filled with electrons.The essence of the principle is that the electrons can have any combination of the above four quantum features atom but can not be composed of two electrons, identical in all quantum characteristics.
main result of the opening of the laws of atomic structure, which contains the Pauli exclusion principle, - physics, ie,nature of the phenomenon, is to fill the shells of electrons.And this, in turn, gave the background to support the periodic law.Thus, the "chemical" laws of general maintenance of the structure of atoms and molecules has received the confirmation of the fundamental physics by building internal "architecture" of the atom.
