The electron is a subatomic particle , symbol [604420]

The electron is a subatomic particle , symbol
e−
or
β−
, whose electric charge is negative one elementary charge .[9] Electrons belong to the
first generation of the lepton particle family ,[10] and are generally thought to be elementary
particles because they have no know n components or substructure .[1] The electron has
a mass that is approximately 1/1836 that of the proton .[11] Quantum mechanical properties of the
electron include an intrinsic angular momentum (spin) of a half -integer value, expressed in units
of the reduced Planck constant , ħ. Being fermions , no two electrons can occupy the
same quantum state , in accordance with the Pauli exclusion principle .[10] Like all elemen tary
particles, electrons exhibit properties of both particles and waves : they can collide with other
particles and can be diffracted like light. The wave properties of electrons are easier to observe
with experiments than those of other particl es like neutrons and protons because electrons have
a lower mass and hence a longer de Broglie wavelength for a given energy.
Electrons play an essential role in numerous physical phenomena, such
as electricity , magnetism , chemistry and thermal conductivity , and they also participate
in gravitational , electromagnetic and weak interactions .[12] Since an electron has charge, it has a
surrounding electric field , and if that electron is moving relative to an observer, said observer will
observe it to generate a magnetic field . Electromagnetic fields produced from other sources will
affect the motion of an electron according to the Lorentz force law . Electrons radiate or absorb
energy in the form of photons when they are accelerated. Laboratory instruments are capable of
trapping individual electrons as well as electron plasma by the use of electromagnet ic fields.
Special telescopes can detect electron plasma in outer space. Electrons are involved in many
applications such as electronics , welding , cathode ray tubes , electron microscopes , radiation
therapy , lasers , gaseous ionization detectors and particle accelerators .
Interactions involving electrons with other subatomic particles are of interest in fields such
as chemistry and nuclear physics . The Coulomb force interaction between the
positive protons within atomic nuclei and the negative electrons without, allows the composition of
the two known as atoms . Ionization or differences in the proportions of negative electrons versus
positive nuclei changes the binding energy of an atomic system. The exchange or sharing of the
electrons between two or more atoms is the main cause of chemical bonding .[13] In 1838, British
natural philosopher Richard Laming first hypothesized the concept of an indivisible quantity of
electric charge to explain the chemical properties of atoms .[3] Irish physicist George Johnstone
Stoney named this charge 'electron' in 1891, and J. J. Thomson and his team of British physicists
identified it as a particle in 1897 .[5] Electrons can also participate in nuclear reactions , such
as nucleosynthesis in stars , where they are known as beta particles . Electrons can be created
through beta decay of radioactive isotopes and i n high -energy collisions, for instance
when cosmic rays enter the atmosphere. The antiparticle of the elec tron is called the positron ; it is
identical to the electron except that it carries electrical and other charges of the opposite sign.
When an electron collides with a positron , both particles can be annihilated , producing gamma
ray photons .