Physics:Quantum atoms/electron: Difference between revisions
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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 [[Physics:Quantum fermion|fermions]], they obey the [[Physics:Quantum Pauli exclusion principle|Pauli exclusion principle]], which strongly influences the structure of matter.<ref name="Dirac1928">{{cite journal |last=Dirac |first=P. A. M. |title=The Quantum Theory of the Electron |journal=Proceedings of the Royal Society A |year=1928 |volume=117 |pages=610–624}}</ref> | 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 [[Physics:Quantum fermion|fermions]], they obey the [[Physics:Quantum Pauli exclusion principle|Pauli exclusion principle]], which strongly influences the structure of matter.<ref name="Dirac1928">{{cite journal |last=Dirac |first=P. A. M. |title=The Quantum Theory of the Electron |journal=Proceedings of the Royal Society A |year=1928 |volume=117 |pages=610–624}}</ref> | ||
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[[File:Atomic-orbital-clouds spd m0.png|thumb|280px| | [[File:Atomic-orbital-clouds spd m0.png|thumb|280px|Hydrogen atomic orbitals showing electron probability distributions at different energy levels.]] | ||
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Electrons exhibit both particle-like and wave-like behavior, a property known as [[Physics:Quantum Wave–particle duality|wave–particle duality]]. Their motion is described by [[Physics:Quantum mechanics|quantum mechanics]], and the probability of finding an electron in a given region is represented by a [[Physics:Quantum mechanics#Wave functions|wavefunction]].<ref>{{cite book |last=Feynman |first=Richard P. |title=The Feynman Lectures on Physics |publisher=Addison-Wesley |year=1964}}</ref> | Electrons exhibit both particle-like and wave-like behavior, a property known as [[Physics:Quantum Wave–particle duality|wave–particle duality]]. Their motion is described by [[Physics:Quantum mechanics|quantum mechanics]], and the probability of finding an electron in a given region is represented by a [[Physics:Quantum mechanics#Wave functions|wavefunction]].<ref>{{cite book |last=Feynman |first=Richard P. |title=The Feynman Lectures on Physics |publisher=Addison-Wesley |year=1964}}</ref> | ||
The electron has an intrinsic angular momentum called | The electron has an intrinsic angular momentum called spin, equal to . This quantum property produces magnetic effects and is fundamental to the behavior of atoms and solids.<ref>{{cite journal |last=Uhlenbeck |first=George |last2=Goudsmit |first2=Samuel |title=Spinning Electrons and the Structure of Spectra |journal=Nature |year=1926 |volume=117 |pages=264–265}}</ref> | ||
== Atomic structure == | == 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 [[Physics:Quantum Schrödinger equation|Schrödinger equation]].<ref>{{cite journal |last=Schrödinger |first=Erwin |title=Quantisierung als Eigenwertproblem |journal=Annalen der Physik |year=1926}}</ref> | 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 [[Physics:Quantum Schrödinger equation|Schrödinger equation]].<ref>{{cite journal |last=Schrödinger |first=Erwin |title=Quantisierung als Eigenwertproblem |journal=Annalen der Physik |year=1926}}</ref> | ||
The arrangement of electrons around the nucleus forms the basis of the | The arrangement of electrons around the nucleus forms the basis of the periodic table and determines chemical properties. Electrons in the outermost shell, called [[Physics:Quantum atoms/valence electron|valence electrons]], participate in chemical bonding.<ref>{{cite book |last=Pauling |first=Linus |title=The Nature of the Chemical Bond |publisher=Cornell University Press |year=1960}}</ref> | ||
Electron transitions between energy levels produce absorption and emission spectra characteristic of each element.<ref>{{cite book |last=Bohr |first=Niels |title=On the Constitution of Atoms and Molecules |year=1913}}</ref> | Electron transitions between energy levels produce absorption and emission spectra characteristic of each element.<ref>{{cite book |last=Bohr |first=Niels |title=On the Constitution of Atoms and Molecules |year=1913}}</ref> | ||
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== Applications == | == Applications == | ||
Electron beams are widely used in science and technology. Applications include: | 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 [[Physics:Quantum Computing Algorithms in the NISQ Era|quantum computing]], semiconductor devices, and nanoscale electronics.<ref>{{cite book |last=Nielsen |first=Michael |last2=Chuang |first2=Isaac |title=Quantum Computation and Quantum Information |publisher=Cambridge University Press |year=2010}}</ref> | Electrons are also central to modern quantum technologies such as [[Physics:Quantum Computing Algorithms in the NISQ Era|quantum computing]], semiconductor devices, and nanoscale electronics.<ref>{{cite book |last=Nielsen |first=Michael |last2=Chuang |first2=Isaac |title=Quantum Computation and Quantum Information |publisher=Cambridge University Press |year=2010}}</ref> | ||
== History == | == History == | ||
The concept of the electron emerged during studies of electricity and atomic structure in the nineteenth century. In 1897, | 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.<ref>{{cite journal |last=Thomson |first=J. J. |title=Cathode Rays |journal=Philosophical Magazine |year=1897}}</ref> | ||
In 1909, | In 1909, Robert Millikan measured the elementary electric charge using the oil-drop experiment.<ref>{{cite journal |last=Millikan |first=Robert |title=On the Elementary Electrical Charge and the Avogadro Constant |journal=Physical Review |year=1911}}</ref> | ||
The development of [[Physics:Quantum mechanics|quantum mechanics]] in the 1920s provided the theoretical framework necessary to understand electron behavior in atoms. [[Physics:Quantum Dirac equation|Dirac's relativistic equation]] later predicted the existence of antimatter and the positron.<ref name="Dirac1928"/> | The development of [[Physics:Quantum mechanics|quantum mechanics]] in the 1920s provided the theoretical framework necessary to understand electron behavior in atoms. [[Physics:Quantum Dirac equation|Dirac's relativistic equation]] later predicted the existence of antimatter and the positron.<ref name="Dirac1928"/> | ||
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{{Author|Harold Foppele}} | {{Author|Harold Foppele}} | ||
{{Sourceattribution| | {{Sourceattribution|Physics:Quantum atoms/electron|1}} | ||
Latest revision as of 22:05, 20 May 2026
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 . 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 (84 articles)
Index
Full contents
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, Nathan; Podolsky, Boris; Rosen (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.
Source attribution: Physics:Quantum atoms/electron