Electron

of these articles is concerned with the elementary particle electron, further meanings under electron (term clarifying)
Electron
classification
Elementary particle
fermion
lepton
characteristics
Charge - e - =

-1.602 176,462 (63)·10,-19 C

proper mass <math> m_ {\ rm e}< /math> 5,485 799,110 (12)·10 -4 u =

9,109381 88 (72)·10,-31 kg

of rest energy 0.510 998,902 (21) MeV =

8.187 104 14 (64)·10,-14 J

Compton-Wellenlänge <math> \ lambda_ {\ rm e}< /math> 2,4263·10,-12 m
magnetic moment <math> \ vec {\ mu_ {\ rm b}}< /math> -928,476 362 (37)·10,-26 J T -1
spin ±1/2
g-factor 2.002 319,304 3718 (75)
life span stably

Electrons are negatively charged elementary particles without spatial expansion. Their symbol is e -. They form the electron sheath of the atoms (and ions). Such an electron can be described clearly by four quantum numbers (n, l, m and s). Their freeMobility in metals is the cause for the electrical conductivity of metallic leaders.

Electrons belong to the leptons and have a spin of ±1/2. All elementary particles with such spin belong to the class of the fermions. Their antiparticles are those Positrons, symbol e +, with which they agree up to their electrical charge in all characteristics.

The experimental proof of electrons succeeded for the first time in the year 1897 by the Britisher Joseph John Thomson.

The name comes from the Greek Word electron (ηλεκτρον) and means amber, because at it the electricity was observed for the first time. If one rubs amber for example with a cat skin, then it loads itself electrically up. The name electron for the charge unit introduced George John clay/tone Stoney(Philosophical of magazines 40 (1895), 372).

An electron is „a micro object “, D. h. that it, similarly as light, waves - and a particle character has. Hence it follows that it is subject to the Heisenberg uncertainty relation. In an atom the electron becomesusually as standing subject wave regards.

Electrons can go in polar solvents such as water or alcohols into solution. This species is called solvated electron. With solution of alkali metals in ammonia it is responsible for the strong blue color.

These sizes becomeby the magnetic moment of the electron spin links with one another: <math> \ vec {\ mu_ {\ rm s}} =-g_ {\ rm s} \ frac {e} {2m_ {\ rm e}} \ vec {s} </math>. Math <\> vec {\ mu_ {\ rm s is}}< /math> the magnetic moment of the electron spin, <math> m_ {\ rm e}< /math> the proper mass of the electron, <math> e< /math> its charge and <math> \ vec {s}< /math> the spin. <math> g_ {\ rm s}< /math> Landé is called- or g-factor. One seizes the term forwards <math> \ vec s< /math> together, then one keeps the relationship called from magnetic moment to the spin, gyromagnetisches relationship of the electron. For the electron the theoretical value is according to the Dirac theory (relativistic quantum mechanics)by <math> g_ {\ rm s}< /math> accurately directly two. Effects of quantum electrodynamics cause however (slight) a deviation of the value for <math> g_ {\ rm s}< /math> of two.

Electrons form the atoms with protons and neutrons. While the two latter particles form the core, are the electrons in the atomic shell. Electrons are very much more easily than protons and neutrons, approximately around the factor 1836.

In the cathode ray tube and/or. Braun tube withdraw electrons from a heated glow cathode and become in the vacuum by in electrical field in field direction (toward the positive anode) accelerates. The electrons are diverted by magnetic fields perpendicularly to the field direction. These characteristics of the electrons have only the development of the television and the computer monitor as well as their use in technological applications(Electron gun) makes possible.

The mass of a resting electron is always constant. With moved electrons (and an electron always is under normal conditions in motion) the mass increase of relativity theory must be considered. At electrons this mass increase can be well observed,since they easily due to their charge and small measures on high speeds to accelerate leave themselves. The mass can be determined then by diverson in a magnetic field.

After the theoretical representations of quantum electrodynamics the electron becomes as point particle, without finite expansionassumed. In good agreement with it scattering experiments at particle accelerators a maximum electron size of 10,-19 M. resulted in electron electron.

From the size to to differentiate is the activation cross-section. During the dispersion of X-ray at electrons one receives an activation cross-section some effectiveElektronenradius of approximately 3·would correspond to 10 ,-15 m. The same order of magnitude would result in the case of a classical (not quantum-theoretical) description of the electron on the assumption:

  1. Electrons are spherical, them form a ball condenser
  2. the charge are at the surface distribute
  3. the potential energy thatCharge corresponds to the rest energy <math> m_ {\ rm e} c^2< /math>.


Wiktionary: Electron - to word origin, synonyms and translations

see also Stern-Gerlach attempt

 

  > German to English > de.wikipedia.org (Machine translated into English)