What is it the electron?
An electron is a negatively charged, stable elementary particle that is one of the fundamental components of the atom. For this reason, it can also be defined as a subatomic particle. It’s part of the lepton group.
Electrons can appear in a free state (without being attached to any atom) or tied to the nucleus of an atom. There are electrons in atoms in spherical layers of various radii.
These spherical layers represent the energy levels. The larger the spherical shell, the greater the energy contained in the electron.
In electrical conductors, current flows are the electrons of atoms that circulate individually from one atom to another in the direction of the negative pole to the positive pole of the electrical conductor.
The semiconductor materials, electrical current is also produced by the movement of electrons.
In some cases, the most illustrative for visualizing the motion of the electric current is the deficiencies of electrons from atom to atom. An electron-deficient atom in a semiconductor is called a hole. The holes generally”move” between the electrical poles from positive to negative.
The mass of the electron is about 1,800 times less than the mass of the proton. Although electrons are usually part of atoms, there are electrons that form beams in a vacuum or that move independently through matter. If electrons move outside the atom, they can form the electric current.
Characteristics of the electrons
Electrons have a negative electrical charge, with a magnitude sometimes called elemental charge or fundamental charge. This is why it is said that an electron has a charge of -1.
The protons have a charge of the same value, but with opposite polarity, i.e. +1. The fundamental load has a value of 1,602 x 10-19 coulomb.
The equivalent of the electron in antimatter is the positron. The positron has the same amount of electrical charge as the electron, but positive. The spin and mass are equal in electron and positron.
When an electron and a positron collide, they annihilate each other and two photons with an energy of 0.500 MeV each originates.
How the electron was discovered
J.J. Thomson was studying the properties of the cathode ray and this study led him to conclude in 1897 that cathode rays were made up of light particles with a negative electrical charge, now known as electrons. Thomson was awarded the Nobel Prize for Physics in 1906.
What does the word electron mean?
The word “elektron“ in Greek means amber, the yellow fossilized resin of evergreen trees, a”natural plastic material” already known to the ancient Greeks.
It was known that when amber was rubbed with a dry cloth, producing what would now be called static electricity, it could attract light objects, such as scraps of paper.
William Gilbert, a doctor who lived in London at the time of Queen Elizabeth I and Shakespeare, studied magnetic phenomena and demonstrated that the earth itself was a huge magnet, through his”earthy” experiment.
But he also studied the attraction produced when materials such as amber were rubbed together and called it the”electric” attraction. From that, came the word”electricity” and all the others derived from it.
History and discovery of the electron
The electron was the first elementary particle discovered. Towards the end of the 19th century, considerable effort was devoted to investigating electrical discharges in rarefied gases.
In 1895 Jean Perrin, analyzing the electrical charge of the so-called cathode rays (cathode), showed that they carried a negative charge.
Soon after, J.J. Thomson conducted the classic experiment in which he was able to determine the specific charge of the particles. According to Thomson, the charges were cathode rays and he called them electrons.
Millikan took advantage of the load/mass ratio (e/m) obtained by Thomson to perform a new experiment. The Millikan experiment became famous and was able to measure electron charge and mass m in 1909.
The discovery of the electron began a new stage in physics. It was possible to corroborate the hypothesis that the electron is an elementary particle of the Universe from which all atoms are formed.
It has been proven that the electron mass increases with speed, according to the predictions of the relativistic mechanics of Albert Einstein. The wave nature of the electron has also been verified.
The production of free electrons by different processes and their behaviour in different environments have found an extraordinary practical application and have led to the development of a new branch of physics and electricity, electronics.
Physical properties of electrons
The charge of a single electron is considered to be the unit of electrical charge. Negative polarity is assigned, so we say that the electron has a negative charge. The charge of an electron is equal, but in the opposite direction, to the positive charge of a proton or a hole.
The amount of electrical charge is not measured in terms of the charge of an electron because it is extremely small. Instead, the Coulomb is used, with symbol C. The Coulomb is the standard unit of electrical charge quantity. A Coulomb represents about 6.24 x 1018 electrons.
The electrical charge of an electron is 1.60 x 10-19 C and the electron mass is approximately 9.11 x 10-31 kg.
Electrons move at an appreciable fraction of the speed of light, for example, in a particle accelerator, they have a greater mass because of the relativistic effects.
Important Electron Data
Electrons, quarks up, quarks down and neutrinos are the only stable particles in the universe. The other particles have ephemeral existence and last for fractions of a second.
Electrons are not affected by strong nuclear interaction. This is why, although the majority of electrons are found to be part of atoms, there are atoms that move independently through matter or form a beam in a vacuum.
Electrons are a key element in electromagnetism, a theory that is suitable from a classical point of view, applicable to macroscopic systems.
Scientists estimate that the number of electrons in the known universe is at least 1079.
Virtually no new electrons have appeared after primordial nucleosynthesis when the temperature of the universe dropped to 10 billion degrees.