The electron is a subatomic particle with a negative electric charge that is believed to be an elementary particle.
Electrons, along with protons and neutrons, are components of atoms and, although they contribute to the total mass of the atom by less than 0.06%, they significantly characterize nature and determine its chemical properties: the chemical bond Covalent bond is formed by following the exchange of electrons between two or more atoms.
The movement of the electron generates a magnetic field, while the variation of its energy and its acceleration cause the emission of photons; It is also responsible for conducting electrical current and heat.
The advent of electronics and the relative development of information technology have made the electron the protagonist of technological development in the 20th century. Its properties are exploited in a variety of applications, such as cathode ray tubes, electron microscopes, radiation therapy, and lasers.
In the standard model of particle physics, electrons belong to the group of subatomic particles called leptons, which are believed to be elementary particles, and have less mass than any other known charged particle.
The electron belongs to the first generation of fundamental particles, while the second and third generations contain other charged leptons, the muon and the tauone, which have identical charge and spin, but the mass at rest is greater. The electron and all leptons differ from the other fundamental components of matter (which are quark, which make up protons and neutrons) due to the fact that they are not affected by the force of strong nuclear interaction.
The electron is an elementary particle with spin 1/2, making it a fermion, like the proton, neutron, and positron. The antiparticle of the electron is called a positron. As far as is known, the electron has no more internal structure. According to string theory, the electron, like other elementary particles, is a certain pattern of vibration in a one-dimensional string. However, there is still a lot of debate about this theory.
The electron has a negative charge equal to the elementary charge quantum e (1.6022 × 10 −19 coulomb), first measured by Robert Millikan with his oil drop experiment.
According to the standard model of particle physics, electric charges can only occur in multiples of 1 e.
The resting mass of the electron is 9.10938356 (11) × 10 −31 kg  , which is 1/1836 of the mass of a proton and corresponds to a resting energy of 511 keV. The electron, like a photon, also has wave properties and is subject to the duality of waves and particles according to the de Broglie hypothesis. This wave property of electrons is applied within the electron microscope.
The electronic configuration largely determines the chemical behavior of the atom.
In conductors, freely moving electrons provide electrical conductivity. When the electrons in the conductor, for example a copper wire, go on average in a certain direction, this is called the electric current in that conductor.
The conductor and the insulator are opposite each other. An insulator is a substance in which electric current cannot flow, there are no free electrons in an insulator. The movements of the electrons are limited in their atom. There are as many electrons as there are energy levels. Electrons can only change places, but nothing changes in energy levels. In an electric field, the positively charged atomic nucleus and the orbits of negatively charged electrons change each other, an effect called polarization.
Static electricity occurs when an object contains more or fewer electrons than is necessary to cancel the positive charge of the protons in the nucleus.