Physics:Quantum atoms/electron
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An electron is a stable subatomic particle with a negative elementary electric charge. It is one of the fundamental components of ordinary matter and belongs to the group of particles known as leptons. Electrons are generally bound to atomic nuclei by the electromagnetic force and occupy atomic orbitals that determine the chemical and physical properties of matter.[1]
Electrons can exist freely or bound within atoms. They are responsible for electricity, magnetism, chemical bonding, thermal conductivity, and many optical phenomena. Because electrons are fermions, they obey the Pauli exclusion principle, which strongly influences the structure of matter.[2]
Description
The electron is considered an elementary particle, meaning that it has no known internal structure.[3] It has a mass of approximately 9.109 × 10−31 kilograms and an electric charge of −1.602 × 10−19 coulombs.[1]
Electrons exhibit both particle-like and wave-like behavior, a property known as wave–particle duality. Their motion is described by quantum mechanics, and the probability of finding an electron in a given region is represented by a wavefunction.[4]
The electron has an intrinsic angular momentum called spin, equal to 1/2. This quantum property produces magnetic effects and is fundamental to the behavior of atoms and solids.[5]
Atomic structure
Electrons are bound to positively charged nuclei by the electromagnetic interaction. In atoms, electrons occupy discrete energy levels and orbitals described by solutions of the Schrödinger equation.[6]
The arrangement of electrons around the nucleus forms the basis of the periodic table and determines chemical properties. Electrons in the outermost shell, called valence electrons, participate in chemical bonding.[7]
Electron transitions between energy levels produce absorption and emission spectra characteristic of each element.[8]
Quantum properties
Electrons obey Fermi–Dirac statistics and cannot occupy identical quantum states simultaneously. This exclusion principle explains the stability and structure of atoms and condensed matter.[9]
The electron magnetic moment is closely related to its spin and is measured with extremely high precision. Quantum electrodynamics predicts the electron magnetic moment with remarkable agreement between theory and experiment.[10]
Electrons may become quantum mechanically entangled with other particles, producing correlations that cannot be explained classically.[11]
Interactions
Electrons interact primarily through the electromagnetic force. Accelerated electrons emit electromagnetic radiation in the form of photons.[12]
An electron and its antiparticle, the positron, can annihilate each other to produce gamma rays:
This process is important in particle physics, astrophysics, and medical imaging technologies such as positron emission tomography.[13]
Electrons also participate in weak interactions responsible for radioactive beta decay.[14]
Conductivity
In conductive materials such as metals, some electrons become delocalized and form an electron gas capable of moving freely through the material. This motion produces electric current.[15]
In semiconductors, electron transport can be controlled using impurities, electric fields, and quantum structures. Semiconductor electronics form the basis of transistors, integrated circuits, and computers.[16]
Superconductivity occurs when electrons form correlated quantum states known as Cooper pairs, allowing electrical current to flow without resistance.[17]
Applications
Electron beams are widely used in science and technology. Applications include:
- electron microscopy
- particle accelerators
- electron-beam welding
- electron-beam lithography
- radiation therapy
- synchrotron radiation
- cathode-ray tubes
Electrons are also central to modern quantum technologies such as quantum computing, semiconductor devices, and nanoscale electronics.[18]
History
The concept of the electron emerged during studies of electricity and atomic structure in the nineteenth century. In 1897, J. J. Thomson demonstrated that cathode rays consisted of negatively charged particles much smaller than atoms.[19]
In 1909, Robert Millikan measured the elementary electric charge using the oil-drop experiment.[20]
The development of quantum mechanics in the 1920s provided the theoretical framework necessary to understand electron behavior in atoms. Dirac's relativistic equation later predicted the existence of antimatter and the positron.[2]
Experiments throughout the twentieth century confirmed wave–particle duality, spin, quantum statistics, and the role of electrons in atomic and condensed matter physics.[21]
See also
Table of contents (136 articles)
Index
Full contents
- Physics:Quantum Interpretations of quantum mechanics
- Physics:Quantum Wave–particle duality
- Physics:Quantum Complementarity principle
- Physics:Quantum Uncertainty principle
- Physics:Quantum Measurement problem
- Physics:Quantum Bell's theorem
- Physics:Quantum Hidden variable theory
- Physics:Quantum A Spooky Action at a Distance
- Physics:Quantum A Walk Through the Universe
- Physics:Quantum The Secret of Cohesion and How Waves Hold Matter Together
- Physics:Quantum Density matrix
- Physics:Quantum Exactly solvable quantum systems
- Physics:Quantum Formulas Collection
- Physics:Quantum A Matter Of Size
- Physics:Quantum Symmetry in quantum mechanics
- Physics:Quantum Angular momentum operator
- Physics:Quantum Runge–Lenz vector
- Physics:Quantum Approximation Methods
- Physics:Quantum Matter Elements and Particles
- Physics:Quantum Dirac equation
- Physics:Quantum Klein–Gordon equation
- Physics:Quantum Atomic structure and spectroscopy
- Physics:Quantum Hydrogen atom
- Physics:Quantum Multi-electron atoms
- Physics:Quantum Fine structure
- Physics:Quantum Hyperfine structure
- Physics:Quantum Isotopic shift
- Physics:Quantum Zeeman effect
- Physics:Quantum Stark effect
- Physics:Quantum Spectral lines and series
- Physics:Quantum Selection rules
- Physics:Quantum Fermi's golden rule
- Physics:Quantum Wavefunction
- Physics:Quantum Superposition principle
- Physics:Quantum Eigenstates and eigenvalues
- Physics:Quantum Boundary conditions and quantization
- Physics:Quantum Standing waves and modes
- Physics:Quantum Normal modes and field quantization
- Physics:Number of independent spatial modes in a spherical volume
- Physics:Quantum Density of states
- Physics:Quantum Time evolution
- Physics:Quantum Schrödinger equation
- Physics:Quantum Time-dependent Schrödinger equation
- Physics:Quantum Stationary states
- Physics:Quantum Perturbation theory
- Physics:Quantum Time-dependent perturbation theory
- Physics:Quantum Adiabatic theorem
- Physics:Quantum Scattering theory
- Physics:Quantum S-matrix
- Physics:Quantum Nonlinear King plot anomaly in calcium isotope spectroscopy
- Physics:Quantum optics beam splitter experiments
- Physics:Quantum Ultra fast lasers
- Physics:Quantum Experimental quantum physics Template:Quantum optics operators
- Physics:Quantum field theory (QFT) basics
- Physics:Quantum field theory (QFT) core
- Physics:Quantum Fields and Particles
- Physics:Quantum Second quantization
- Physics:Quantum Harmonic Oscillator field modes
- Physics:Quantum Creation and annihilation operators
- Physics:Quantum vacuum fluctuations
- Physics:Quantum Propagators in quantum field theory
- Physics:Quantum Feynman diagrams
- Physics:Quantum Path integral formulation
- Physics:Quantum Renormalization in field theory
- Physics:Quantum Renormalization group
- Physics:Quantum Field Theory Gauge symmetry
- Physics:Quantum Non-Abelian gauge theory
- Physics:Quantum Electrodynamics (QED)
- Physics:Quantum chromodynamics (QCD)
- Physics:Quantum Electroweak theory
- Physics:Quantum Standard Model
- Physics:Quantum Statistical mechanics
- Physics:Quantum Partition function
- Physics:Quantum Distribution functions
- Physics:Quantum Liouville equation
- Physics:Quantum Kinetic theory
- Physics:Quantum Boltzmann equation
- Physics:Quantum BBGKY hierarchy
- Physics:Quantum Relaxation and thermalization
- Physics:Quantum Thermodynamics
- Physics:Quantum Fusion reactions and Lawson criterion
- Physics:Quantum Plasma (fusion context)
- Physics:Quantum Magnetic confinement fusion
- Physics:Quantum Inertial confinement fusion
- Physics:Quantum Plasma instabilities and turbulence
- Physics:Quantum Tokamak core plasma
- Physics:Quantum Tokamak edge physics and recycling asymmetries
- Physics:Quantum Stellarator
- Physics:Quantum mechanics/Timeline
- Physics:Quantum mechanics/Timeline/Pre-quantum era
- Physics:Quantum mechanics/Timeline/Old quantum theory
- Physics:Quantum mechanics/Timeline/Modern quantum mechanics
- Physics:Quantum mechanics/Timeline/Quantum field theory era
- Physics:Quantum mechanics/Timeline/Quantum information era
- Physics:Quantum mechanics/Timeline/Quantum technology era
- Physics:Quantum mechanics/Timeline/Quiz
References
- ↑ 1.0 1.1 "CODATA Value: electron mass". NIST. https://physics.nist.gov/cgi-bin/cuu/Value?me.
- ↑ 2.0 2.1 Dirac, P. A. M. (1928). "The Quantum Theory of the Electron". Proceedings of the Royal Society A 117: 610–624.
- ↑ Griffiths, David (2008). Introduction to Elementary Particles. Wiley.
- ↑ Feynman, Richard P. (1964). The Feynman Lectures on Physics. Addison-Wesley.
- ↑ Uhlenbeck, George; Goudsmit, Samuel (1926). "Spinning Electrons and the Structure of Spectra". Nature 117: 264–265.
- ↑ Schrödinger, Erwin (1926). "Quantisierung als Eigenwertproblem". Annalen der Physik.
- ↑ Pauling, Linus (1960). The Nature of the Chemical Bond. Cornell University Press.
- ↑ Bohr, Niels (1913). On the Constitution of Atoms and Molecules.
- ↑ Pauli, Wolfgang (1925). "Über den Zusammenhang des Abschlusses der Elektronengruppen im Atom mit der Komplexstruktur der Spektren". Zeitschrift für Physik.
- ↑ Schwinger, Julian (1948). "On Quantum-Electrodynamics and the Magnetic Moment of the Electron". Physical Review 73: 416–417.
- ↑ Einstein, Albert; Podolsky, Boris; Rosen, Nathan (1935). "Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?". Physical Review 47: 777–780.
- ↑ Jackson, John David (1998). Classical Electrodynamics. Wiley.
- ↑ Perkins, Donald (2000). Introduction to High Energy Physics. Cambridge University Press.
- ↑ Fermi, Enrico (1934). "Versuch einer Theorie der β-Strahlen". Zeitschrift für Physik.
- ↑ Ashcroft, Neil; Mermin, N. David (1976). Solid State Physics. Brooks Cole.
- ↑ Sze, Simon (2006). Physics of Semiconductor Devices. Wiley.
- ↑ Bardeen, John; Cooper, Leon; Schrieffer, Robert (1957). "Theory of Superconductivity". Physical Review.
- ↑ Nielsen, Michael; Chuang, Isaac (2010). Quantum Computation and Quantum Information. Cambridge University Press.
- ↑ Thomson, J. J. (1897). "Cathode Rays". Philosophical Magazine.
- ↑ Millikan, Robert (1911). "On the Elementary Electrical Charge and the Avogadro Constant". Physical Review.
- ↑ Pais, Abraham (1986). Inward Bound. Oxford University Press.
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