Electrons are what? Properties and history of the discovery of electrons

Everything around us on the planet consists of small, elusive particles. Electrons are one of them. Their discovery occurred relatively recently. And it opened new ideas about the structure of the atom, the mechanisms of electricity transmission and the organization of the world as a whole.

How divided the indivisible

In the modern understanding, electrons are elementary particles. They are integral and do not split into smaller structures. But this idea did not always exist. Until 1897, the electrons had no concept.

Still thinkers of Ancient Greece guessed that every thing in the world, like a building, consists of many microscopic "bricks". The smallest unit of matter then was an atom, and this belief persisted for centuries.

The idea of an atom changed only at the end of the XIX century. After the investigations of J. Thomson, E. Rutherford, H. Lorenz, P. Zeeman, the smallest indivisible particles were recognized as atomic nuclei and electrons. In time, protons, neutrons were discovered, and even later - neutrinos, kaons, pions, etc.

Now science knows a huge number of elementary particles, its place among which invariably occupy and electrons.

The discovery of a new particle

By the time when the electrons were discovered in the atom, scientists have long known about the existence of electricity and magnetism. But the true nature and full properties of these phenomena are still a mystery, occupying the minds of many physicists.

Already at the beginning of the XIX century it was known that the propagation of electromagnetic radiation occurs at the speed of light. However, the Englishman Joseph Thomson, conducting experiments with cathode rays, concluded that they consist of many small grains, the mass of which is less than the atomic mass.

In April 1897, Thomson made a report, where he presented the scientific community the birth of a new particle in the atom, which he called a corpuscle. Later Ernest Rutherford , using experiments with foil, confirmed the conclusions of his teacher, and the corpuscles were given another name - "electrons."

This discovery pushed the development of not only physical, but also chemical science. It made it possible to advance considerably in the study of electricity and magnetism, the properties of substances, and also gave rise to nuclear physics.

What is an electron?

Electrons are the lightest particles that have an electric charge. Our knowledge of them is still largely contradictory and incomplete. For example, in modern concepts they live forever, as they never decay, unlike neutrons and protons (the theoretical age of decay of the latter exceeds the age of the universe).

The electrons are stable and have a constant negative charge e = 1.6 × 10 ^-19 Celsius. They are referred to the family of fermions and a group of leptons. The particles participate in a weak electromagnetic and gravitational interaction. They are in the composition of atoms. Particles that have lost contact with atoms are free electrons.

The mass of electrons is 9.1 × 10 ^-31 kg and is 1836 times less than the proton mass. They have a half-integral and spin, and a magnetic moment. The electron is indicated by the letter "e ^- ". Similarly, but with a plus sign, its antagonist - antiparticle positron - is designated.

The state of electrons in an atom

When it turned out that the atom consists of smaller structures, it was necessary to understand exactly how they are located in it. Therefore, at the end of the XIX century, the first models of the atom appear. According to the planetary models, protons (positively charged) and neutrons (neutral) formed the atomic nucleus. And around him on the elliptical orbits moved electrons.

These ideas change with the advent of quantum physics in the early twentieth century. Louis de Broglie proposes the theory that the electron manifests itself not only as a particle, but also as a wave. Erwin Schrodinger creates a wave model of the atom, where the electrons are represented as clouds of a certain density with a charge.

It is almost impossible to accurately determine the location and trajectory of the motion of electrons around the nucleus. In connection with this, a special concept is introduced, "orbital" or "electronic cloud", which is the space of the most probable arrangement of the named particles.

Energy levels

Electrons in the cloud around the atom are exactly as many as protons in its core. All of them are at different distances. The closest to the nucleus are the electrons with the least amount of energy. The more energy is in the particles, the further they can be.

But they are not located chaotically, but occupy specific levels that contain only a certain number of particles. Each level has its own amount of energy and is divided into sublevels, and those in turn, into orbitals.

To describe the characteristics and location of electrons at energy levels, four quantum numbers are used :

• N - the main number that determines the energy reserve of the electron (corresponds to the number of the chemical element period);
• L is the orbital number that describes the shape of the electron cloud (s is a spherical shape, p is the figure of eight, d is the shape of a clover or double figure eight, f is a complex geometric shape);
• M is the magnetic number that determines the orientation of the cloud in a magnetic field;
• Ms is the spin number characterizing the inversion of electrons around its axis.

Conclusion

So, electrons are stable, negatively charged particles. They are elementary and can not decay into other elements. They are classified as fundamental particles, that is, those that are part of the structure of matter.

The electrons move around the atomic nuclei and make up their electron shell. They affect the chemical, optical, mechanical and magnetic properties of various substances. These particles participate in the electromagnetic and gravitational interactions. Their directional motion creates an electric current and a magnetic field.