Electron Totally Explained

Everything about Electrons totally explained

The electron is a fundamental subatomic particle that carries a negative electric charge. It is a spin ½ lepton that participates in electromagnetic interactions, and its mass is approximately

1/1836

of that of the proton. Together with atomic nuclei, which consist of protons and neutrons, electrons make up atoms. Their interaction with adjacent nuclei is the main cause of chemical bonding.

History

The name electron comes from the Greek word for amber, ήλεκτρον. This material played an essential role in the discovery of electrical phenomena. The ancient Greeks knew, for example, that rubbing a piece of amber with fur left an electric charge on its surface, which could then create a spark when brought close to a grounded object. For more about the history of the term electricity, see History of electricity.
   The electron as a unit of charge in electrochemistry was posited by G. Johnstone Stoney in 1874, who also coined the term electron in 1894.
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During the late 1890s a number of physicists posited that electricity could be conceived of as being made of discrete units, which were given a variety of names, but the reality of these units hadn't been confirmed in a compelling way.
   The discovery that the electron was a subatomic particle was made in 1897 by J.J. Thomson at the Cavendish Laboratory at Cambridge University, while he was studying cathode ray tubes. A cathode ray tube is a sealed glass cylinder in which two electrodes are separated by a vacuum. When a voltage is applied across the electrodes, cathode rays are generated, causing the tube to glow. Through experimentation, Thomson discovered that the negative charge couldn't be separated from the rays (by the application of magnetism), and that the rays could be deflected by an electric field. He concluded that these rays, rather than being waves, were composed of negatively charged particles he called "corpuscles". He measured their mass-to-charge ratio and found it to be over a thousand times smaller than that of a hydrogen ion, suggesting that they were either very highly charged or very small in mass. Later experiments by other scientists upheld the latter conclusion. Their mass-to-charge ratio was also independent of the choice of cathode material and the gas originally in the vacuum tube. This led Thomson to conclude that they were universal among all materials.
   The electron's charge was carefully measured by R. A. Millikan in his oil-drop experiment of 1909.
   The periodic law states that the chemical properties of elements largely repeat themselves periodically and is the foundation of the periodic table of elements. The law itself was initially explained by the atomic mass of the element. However, as there were anomalies in the periodic table, efforts were made to find a better explanation for it. In 1913, Henry Moseley introduced the concept of the atomic number and explained the periodic law in terms of the number of protons each element has. In the same year, Niels Bohr showed that electrons are the actual foundation of the table. In 1916, Gilbert Newton Lewis explained the chemical bonding of elements by electronic interactions.

Classification

The electron is in the class of subatomic particles called leptons, which are believed to be fundamental particles.
As with all particles, electrons can also act as waves. This is called the wave-particle duality, also known by the term complementarity coined by Niels Bohr, and can be demonstrated using the double-slit experiment.
The antiparticle of an electron is the positron, which has positive rather than negative charge. The discoverer of the positron, Carl D. Anderson, proposed calling standard electrons negatrons, and using electron as a generic term to describe both the positively and negatively charged variants. This usage of the term "negatron" is still occasionally encountered today, and it may also be shortened to "negaton".

Properties and behavior

Electrons have an electric charge of −1.602 × 10⁻¹⁹ C, a mass of 9.11 × 10⁻³¹ kg based on charge/mass measurements equivalent to a rest mass of about 0.511 MeV/c². The mass of the electron is approximately ¹/₁₈₃₆ of the mass of the proton. The common electron symbol is e⁻.
   In the Standard Model of particle physics, the electron is the first-generation charged lepton. It forms a weak isospin doublet with the electron neutrino; these two particles interact with each other through both the charged and neutral current weak interaction. The electron is very similar to the two more massive particles of higher generations, the muon and the tau lepton, which are identical in charge, spin, and interaction, but differ in mass.
   The antimatter counterpart of the electron is the positron. The positron has the same amount of electrical charge as the electron, except that the charge is positive. It has the same mass and spin as the electron. When an electron and a positron meet, they may annihilate each other, giving rise to two gamma-ray photons emitted at roughly 180° to each other. If the electron and positron had negligible momentum, each gamma ray will have an energy of 0.511 MeV. See also Electron-positron annihilation.
   Electrons are a key element in electromagnetism, a theory that's accurate for macroscopic systems, and for classical modelling of microscopic systems.

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