What is Electrons: Definition and 999 Discussions

The electron is a subatomic particle, symbol e− or β−, whose electric charge is negative one elementary charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no known components or substructure. The electron has a mass that is approximately 1/1836 that of the proton. 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. Like all elementary 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 particles 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. 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 electromagnetic fields. Special telescopes can detect electron plasma in outer space. Electrons are involved in many applications such as tribology or frictional charging, electrolysis, electrochemistry, battery technologies, electronics, welding, cathode ray tubes, photoelectricity, photovoltaic solar panels, 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. 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. 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 during the cathode ray tube experiment. 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 in high-energy collisions, for instance when cosmic rays enter the atmosphere. The antiparticle of the electron is called the positron; it is identical to the electron except that it carries electrical charge of the opposite sign. When an electron collides with a positron, both particles can be annihilated, producing gamma ray photons.

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  1. S

    I Are All Electrons Truly Identical?

    I'm just confused on whether not all electrons are identical and if they are, how they are.
  2. H

    I How does QM explain that we see electrons circulating in a magnetic field?

    Hi Pfs. I think that QM can explain the classical things explained by classical physics. Using mean values and so on. We know that in a constant magnetic field an electron will rotate on a circle (at the macroscopic scale approximation) I have the answer for the Larmor precession but how to...
  3. chikchok

    Phonon density of states and density of states of free electrons

    In the following pdf I tried to calculate the density of states of free electrons and phonons. First, I found the free electron DOS in 1D, it turns to be proportional to (energy)^(-1/2) and in 2D it is constant. However, I am not sure I found the DOS for phonons in the second part of the...
  4. P

    A Massless electrons stable if the Universe approaches a de Sitter Universe?

    Hi, All cosmological models with a non-zero cosmological constant will approach a de Sitter universe in the far future. In theory this can means that the most basic group of particle physics should be the de Sitter rather than Poincaré. Mass is a Casmir operator of the Poincare but not of the...
  5. S

    Beam current of positrons and electrons

    a) My idea is: 1. Find the energy created by annihilation process, which is ##E=2mc^2## where m is the mass of electron 2. Find the wavelength of photon by using formula E = hf 3. Find the speed of positron by using the formula of de broglie wavelength 4. Find the p.d by using conservation of...
  6. N

    B Electromagnetic force of Electrons

    If you could command all the electrons in an average human body and get them to spin in synchronicity (a clockwise circle in the horizontal plane) how much magnetic force does that produce? Would it create a force against gravity and make you feel lighter? How much lighter?
  7. L

    What factors determine wattage of electrons flowing through a wire?

    Preface: I am new to physics and am trying to learn on my own, though I hope to take a class soon. I looked for a forum for beginners but didn't see one, but this seemed to be the closest forum. So I hope I can get some help with my question here. If it is the wrong forum, feel free to...
  8. R

    B Electrons, quarks and gluons made from something or nothing?

    Most articles said electrons, quarks and gluons are indivisible thus have no compositions unlike the other particles. So, does that means electrons, quarks and gluons are composed of nothing and these elementary particles are indeed 100% void?
  9. R

    B Are these actually real electrons?

    I'm curious whether the scientists actually show the real electron in this video. Thoughts?
  10. V

    Reason for glass rod losing electrons

    I am not sure if the explanation below is enough. This is a high school level question. When rubbing occurs between glass and silk, then heat energy is produced which provides the energy needed to free up electrons in outermost orbits of atoms in silk or glass. But silk has very tightly bound...
  11. Dario56

    Why Do Atoms Need to Have Free Electrons to Create Covalent Bonds?

    Atoms bond because compounds are more stable or have less energy than individual atoms. Interatomic potential energy depends with distance of atoms and there is a distance at which potential energy has minimum. This distance is a length of the bond. When forming covalent bonds, why is it...
  12. N

    B Do emission nebula glow because of ionised or excited electrons?

    I'm trying to figure out why emission nebulae glow. I read various sites such as a NASA website explaining why they shine; 'The massive stars embedded within the nebula give off enormous amounts of ultraviolet radiation, ionizing the gas and causing it to shine.' The Britanica article on...
  13. qnt200

    B Why is there now evidence of a lag time in the photoelectric effect?

    From: https://opentextbc.ca/universityphysicsv3openstax/chapter/photoelectric-effect/ "The photoelectric effect has three important characteristics that cannot be explained by classical physics: (1) the absence of a lag time, (2) the independence of the kinetic energy of photoelectrons on the...
  14. M

    I Free electrons in an accelerated metal?

    I take a conductor and expose one side to a nearby region of negative charge. The metal's free electrons are repelled, and many collect at the opposite side to the charged region. High School stuff. Okay, so now I accelerate the metal in one direction. What happens to the free electrons...do...
  15. cemtu

    I Exploring Ionised Atoms, Free Electrons & Energy Levels

    Homework Statement:: Ionised atom, free electron, conduction band, donor energy level and acceptor energy level Relevant Equations:: None I have some confusion about the concept of some electronic bands and energy levels. Beyond valance band, in a solid crystal lattice, For an atom, can...
  16. porton

    I Are electrons universal problem solvers?

    Existence of an universal problem solver, a polynomial-time NP-complete algorithm is a $1000000 prize question. But suppose that we were able to know something "simple", e.g. an electron state or electron wave function exactly. Would we be able to solve complex mathematical problems (like...
  17. G

    I How quickly do electrons jump orbitals?

    I would hope something like this would come in handy: ΔEΔt>h/2π. Mainly because it seems relatively simple, although I'm not really sure what the inequality really means, other than there is a certain uncertainty associated with that pair. But there are some things that really muddy the waters...
  18. Magnetons

    Electrons in Electric Fields: Examining Changes

    What changes occur in electron, whenit through in a electric field
  19. P

    Semiconductor -- Conduction and Valence bands

    I am a new to this and I try to understand the basics. So initially once the atoms of silicon come together to form a solid, due to Pauli law no electrons can exist in the same energy state,thus many energy states are formed which together make the bands. My problem starts at this stage where I...
  20. bbbl67

    I What happens to the electrons in a Bose-Einstein Condensate?

    When various atoms are turned into BEC's, are their electrons still arranged in their standard atomic orbitals like at higher temperatures? Or are the electrons free floating around the entire condensate? If the electrons are free-floating, then are they arranging themselves into superconductive...
  21. V

    B What percent of everyday-life electrons are collapsed?

    So if particles such as the electrons when "measured" forsake their probabilistic wave form and manifest into a definite particle form, does that mean for all intent and purpose the electrons of every objects we observe are already collapsed? If that's the case how did the labs get pre-collapse...
  22. A

    A Green's function for tunneling electrons between quantum dots

    Good afternoon! I am writing with such a problem, I hope to find someone who could help me. I'm almost desperate! So, there is such a thing as the Braess paradox, this is a classic paradox for roads and power grids, and there is also such an article...
  23. Helena Wells

    Energy of valence electrons from period of the periodic table

    I am currently studying Electrical Engineering and I have this question: An energy band is formed by the overlapping of atomic orbitals of atoms coming close to each other.I suspect that if the energy of the atomic orbital of the valence electrons of a chemical element is less than the energy of...
  24. C

    Can't solve an equation (Deflection of electrons in electrostatic field)

    Hello everyone! I've tried everything but the equation (3) in "Deflection of electrons in electrostatic field" is impossible. Can someone at least hint me to a a way the composed it ?
  25. PhysicsTest

    Number of electrons emitted photoelectrically

    Spectral response : ##\lambda=\frac{1.24} {E_G}## ->eq(1) Given, ##\lambda = 2537 * 10^{-10} m = 0.2537\mu m ## ##E_G = \frac{1.24} {\lambda} = \frac{1.24} {0.2537} = 4.88 eV## So, i can assume if 10,000 photons illuminate then 10000 electrons will be emitted. But i am mainly confused with the...
  26. guywithdoubts

    Water bending with comb: but where do the electrons go?

    I suppose the stream isn't being charged!
  27. PhysicsTest

    Finding the number of free electrons

    The required number of free electrons to be calculated is ##n = \frac{dv} {AM} = \frac{A_0dv*10^3} {A} ## I know mass of single atom is ##M## The atomic weight of mole of atoms is ##A##. Hence ##A = A_0*M ## ##d = \frac{A} {1} ## -> "1" represents ##1m^3##. I am confused how to proceed further...
  28. PainterGuy

    B Double slit experiment with electrons

    Hi, Could you please help me with the queries below? Thanks in advance! Question 1: I was watching this video. Between 8:36 to 9:44 the following is said: "But only firing particle by single particle at this barrier with the 2 openings and by recording dot by single dot where each of those...
  29. A

    Creating stationary neutrons by colliding protons and electrons

    Lets say, in zero gravity space, you have an incredibly precise collider that slams protons and electrons into each other as perfectly as possible such that all momentum is canceled out and the resulting neutron has no velocity relative to the observer. As protons and electrons continue to...
  30. A

    Thomson scattering -- Photons can only scatter from free electrons?

    Hello , Why does an incoming photon can only scatter from an electron if the electron is not bound top an atom ? Because from what I know a bound electron can absorb a photon then be excited to a higher energy level and then re-emit a photon while transitioning back to it's previous energy...
  31. N

    Number of free conduction electrons in a segment of wire

    I've written a calculator that computes the number of conduction electrons in a segment of wire with a specific gauge. For a 1 ft segment of 24awg copper wire, this is what it prints out. AWG [0 - 36]? 24 Wire length (mm) (0 - inf)? 304.8 AWG 24 radius: 0.255 mm dia: 0.511 mm area...
  32. Raz Matazz

    I Why do electrons never stop moving?

    Whether in vacuum inside a CRT, or in a metal, a potential difference has to be applied for free electrons to move from the negative to the positive terminal. However, the reality is that free electrons are still moving when no voltage is present at the 2 ends of a metal conductor. In this...
  33. J

    Electron moles present in wire cross-section

    So I know current is just coulombs/second. Electrons are also in the unit of coulombs, so I can get coulombs to cancel. 7.9C/s/1.602E-29C = 4.93133E29 1/s Now I just need to get mol on top. There are 6.022E23 electron in a mol so 4.93133E29 1/s / 6.022E23 atoms/mol = 8.1889E5 mol/s. Now my...
  34. Kostik

    Location of electrons (not excess charge) in a conductor [static case]

    In a conductor, excess charge resides on the surface. That seems odd, because one would think that the overall energy of the system could be lowered by allowing some of the excess charge to move inward and away from all the charge on the surface, but obviously that can't be true, because charge...
  35. T

    B Where do the electrons go? (in stellar nuclear fusion)

    I have to give a presentation about natural Radiation and I am very happy about it because it includes Astrophysics. I want to explain to my audience how the stars produce cosmic rays. I thought about explaining to them how nuclear fusion and that kind of stuff works but then I realized that I...
  36. SQUB

    Work function of electrons in a metal

    Hi everyone, I have to solve this homework without having any books where to find the theroical topic or examples, so if you could help me find materials that I can use to understand or you want to try help me understand how to get the solution would be very helpfull. I don't have enough time to...
  37. R

    Can infrared photons also eject electrons in 'photoelectric effect'?

    Hello, I have this question whether it will be possible to generate electricity by heating up a suitable metal (conductor). We know from the photoelectric effect that high energy photons (of visible light; probably with frequency closer to that of violet) can knock off the outer electrons from...
  38. F

    A Taking all the electrons away from a real conductor

    How many electrons can you remove from a solid substance before it breaks down at a chemical level? Thinking this through myself, you can create positively or negatively charged objects to a degree, especially with a metallic conductor that can tolerate a loss of charge at the cost of the...
  39. jjson775

    Quantum numbers for p-mesons substituted for electrons

    n = 3, l = 2, me = -2, -1, 0, 1, 2. ms = -1 or 1. The correct answer is that ms can also be 0. Why?
  40. Adams2020

    I Loss of electron & proton energy due to radiation

    Can you compare the energy loss of electrons and protons due to the radiation they emit? In fact, I want to know which of the two loses more energy when it emits radiation.
  41. E

    How will electrons flow in a very long conductor?

    I have two charged spheres connected to different ends of an infinitely long conductor. The first sphere has positive charge, another sphere has negative charge. Suppose that the electric field of the first sphere at point A is zero, and the electric field of the second sphere is zero at point...
  42. E

    How do electrons move in a conductor?

    I have a positively charged sphere that is connected with a conductor to a negatively charged sphere. Positively charged sphere will take electrons from conductor. Then the end of conductor expierences lack of electrons and take them from the nearest atoms of conductor. When it gets to the other...
  43. A

    Magnetic mirror concept -- electrons vs ions

    I am reading a book on fusion and just went over a paragraph of magnetic mirror confinement. What I want to understand is this. So all charged particles gyrate around magnetic field lines and if they have also a velocity parallel to the field they form helical paths. The gyroradius is...
  44. Mayan Fung

    Why don't high-voltage electrons in a metal wire escape?

    The work function of a metal is typically several eV. When we transmit electricity through cables of some 10-100kV, how come the electrons not having enough energy to escape from the metal?
  45. DarkMattrHole

    I Entanglement of Electrons Through Experiments: What's Possible?

    My understanding is that an elementary particle A becomes entangled when it interacts with another particle B, sharing symmetrical properties with particle B, until particle A interacts with another particle C, whereupon particle A becomes entangled with particle C. When an electron gets fired...
  46. F

    B Why don't electrons fall into the nucleus?.

    The first result to this question in Google gives this: "An electron in an atom spreads out according to its energy. The states with more energy are more spread out. All electron states overlap with the nucleus, so the concept of an electron "falling into" or "entering" the nucleus does not...
  47. J

    B Speed of electrons in a 2-slit experiment

    In the 2-slit experiment using electrons, what speed do they travel at?
  48. P

    Finding the excess electrons per lead atom

    a. This is easy with ## q = n*e ## ## 3.2 * 10^{-9} = n * 1.6*10^{-19} ## ## n = 2*10^{10} ## electrons b. Total Lead atoms are ## \frac {8 * 6.022*10^{23}} {207} = 2.3 *10^{22} ## I used the Avogadro number. Total electrons = ## 2.3 * 10^{22} * 82 = 1.88 * 10^{20} ##, here i multiplied with...
  49. tanaygupta2000

    Electrons impinging on a crystal

    Since the crystal spacing is given to be 0.4 nm, so d = 0.4 nm = 4e-10 m in Bragg's law formula For θ = 90° & n = 1, I got λ = 2d = 8e-10 m Using this value in De-broglie wavelength, I got p = h/λ = 8.28e-25 Now kinetic energy of the electrons is given by E = p^2/2m Using value of p, I am...
  50. P

    I Jonsson’s apparatus for photons rather than electrons

    In the prompt 4c in this problem set: https://ocw.mit.edu/courses/physics/8-04-quantum-physics-i-spring-2013/assignments/MIT8_04S13_ps1.pdf. We are asked to find out how d, D and w will change (where d is the slit width, D is the distance from the slits to the screen and w is the distance...
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