What is Electrons: Definition and 998 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. J

    I What effect do gravitons have on electrons?

    Hi, what effect do gravitons have on electrons. I know with photons the electrons absorb the photons and leave the atom. Would gravitons have the same effect?
  2. S

    I Probing into protons with high-energy particles

    What is easily seen about how the internal structure of proton is explored is collisions of proton with electrons of high and varied energy. Electrons have an advantage that they are simple particles easy to handle: muons and tauons are short lived neutrinos are hard to aim and detect other...
  3. Zahid Iftikhar

    B Question about Electrostatic Induction -- The electrons have to pass through the positively charged disc?

    My explantion of this electrostatic induction is that if the disc of electroscope is ground, electrons will flow from the ground and neutralize the disc, leaving the electroscope negatively charged after removal of the ground, but the book says it should be postively charged. As per book, the...
  4. bmhiggs

    I Why does resistance reduce current in whole circuit?

    Ohm's law states that current is inversely proportional to resistance, but on the quantum level, why does that actually slow the current down for the whole circuit? In all of the basic explanations, it talks about how the more densely packed matter in the resistor creates more collisions and...
  5. scythe327

    B Can a hypothetical atom be made out of positrons and electrons ?

    I am a Computer Science Engineering student at a local university in India and I was really moved by the CERN youtube channel and it got me curious about the particles like electrons and protons, I love symmetry in nature and was not a huge fan of proton being nearly 2000 times the mass of...
  6. milkism

    I Do valence electrons determine electrical conductivity?

    I have trouble researching whether valence-electrons take part in electrical conductivity. Some sources say that a lower amount of valence electrons lead to an higher electrical conductivity, whilst others say the opposite. And each have their different reasons, for example, lower valence...
  7. Mustafa Bayram

    B The Mystery of Excited Electrons: Are They Moving Away from the Nucleus?

    when an electron is excited to the conduction band is it move further from the nucleus? Are free electrons in the conduction band further from valence electrons? I saw this picture that seems problematic to me. what do you think?
  8. J

    Electrons travel in wire

    300 000km connect light bulb and battery. I would say 1sec is need from I turn on switch to light start lighting. This video say it is 1m/c...Is this video wrong? Do electron travels thorugh wire, if 300 000km wire is connected to bulb ,why electricitly travel through space only 1m??
  9. Isaac0427

    I Weakly interacting electrons in an atom

    Consider electrons in atom, and let's mostly ignore interactions between the electrons for now. What I mean by that is that the lowest energy level is the doubly degenerate 1s, then the doubly degenerate 2s, then the 6-fold degenerate 2p, etc. Textbooks like Griffiths use term symbols...
  10. ergospherical

    Electrons escaping a metal surface

    In the low temperature limit ##\mu \approx E_F## and the Fermi-Dirac distribution is ##n(E) \approx g(E)/(e^{\beta(E-E_F)}+1)##. An escaping electron contributes ##\Delta j_z = -ev_z = -ep_z/m## to the current density. How can I calculate the rate that electrons escape at? I can't see how to...
  11. Vectronix

    B Electrons at Absolute Zero -- do they still move?

    Can we all agree that electrons still move at absolute zero?
  12. Philip Koeck

    A Characterizing Electron Beam w/ CMOS-Camera or Faraday Cup

    I want to characterize an electron beam using something like a CMOS-camera or maybe just a Faraday cup. The electron energy is between 1 and 10 keV and the expected total current around 10 microA for 1 keV electrons. Essentially I want to see whether the beam diameter is around 1 micrometer...
  13. E

    A Can four electrons form a completely antisymmetric joint spin WF?

    Can four (or more) electrons form a completely antisymmetric joint spin wave function?
  14. snoopies622

    B Are electrons in atoms always in eigenstates?

    Going back to high school chemistry, i remember being taught that the electrons in an atom can each be identified with four quantum numbers - one for energy, two for angular momentum and one for spin. These numbers are integers except for the spin quantum numbers, which are either 1/2 or -1/2...
  15. Lotto

    B For what elements does Born–Oppenheimer approximation fail the most?

    I would say that for the elements with the lowest atomic numbers, because these elements have their nuclei the lightest and so they can move more and their movement influence electrons more than in some heavier elements, whose nuclei move less. Am I right or not?
  16. C

    Perfectly elastic collision between two electrons in ⊥ B-field

    For this problem, The solution is, However, is the reason why they don't include electrical potential energy because the time interval for which we are applying conservation of energy over is very small so the change in electric potential energy is negligible? Also, when they said, "electrons...
  17. StanislavD

    A Superconducting and normal electrons are not interchangeable

    An interesting paper in NATURE "A superconductor free of quasiparticles for seconds" https://www.nature.com/articles/s41567-021-01433-7 showing that superconducting (paired) electrons don't hop into normal states for seconds. The measurement device detects single pair-breaking-events for a large...
  18. H

    B How hard have they banged on quarks, electrons, etc.?

    I think there are so far as we can tell particles of mass that are made up of quarks and leptons (electrons and what not). So far as we know those the fundamental particles of matter. Question - how hard have we banged on quarks/leptons to see if we can blow those up into smaller units? I...
  19. Philip Koeck

    A Fast electrons passing a beam of slow electrons at a right angle

    I'm wondering what happens when fast electrons (100 - 300 keV) interact with a beam (diameter 1 to 10 μm) of slower electrons (1 to 10 keV), which is at right angles to the trajectories of the fast electrons. The beam of slower electrons is relatively dense with 1 to 10 electrons per μm line...
  20. Philip Koeck

    I Is elastic scattering of electrons by a solid possible?

    In electron microscopy of thin solid specimens elastic scattering is treated as the main process responsible for formation of (phase contrast) images and diffraction patterns. However, if an electron changes direction it should lose energy by producing a breaking radiation photon. How can it be...
  21. M

    I Fundamental - Magnetic fields generated by moving electrons

    Trying to understand something fundamental about how magnetic fields are generated by moving electrons in a conductor. I have read many forums, studied Emag and am left with more questions. Looking for some practical insight not Bio-Savart derivations, etc. These still do not explain why the...
  22. Feynstein100

    B How many electrons to make a stable gravitational object?

    I was wondering if we could have an object made up of only electrons. Normally, that wouldn't be possible because electrons repel each other. However, this repulsion can be overcome using gravity. So my question is, how many electrons would you need to have their gravitational attraction...
  23. pokespriter

    I About the position of electrons (uncertainty)

    Hello guys, I don't know if this is the right place to ask, so please be kind :/ I have a question regarding the location of an electron that belongs to an atom. A teacher told me that the probability of an electron to be found within its orbital is around 99%. When I asked about the remaining...
  24. B

    I Separation of Plasma into positive nucleus and negative electrons

    Im wondering if plasma is possible to be separated into a positive nucleus and negative electrons and contained within a magnetic bottle ? If possible, what is the most efficient method of achieving it ?
  25. J

    I Exploring the Octet Rule: Why 8 Valence Electrons are Ideal

    Hello, all! I've been trying to understand why the octet rule is followed, but I have not had much luck yet. Does anyone know why 8 valence electrons are ideal for the stability of atoms? I appreciate any help you can give!
  26. V

    How does the electroscope lose electrons to the Earth?

    I get step 1, in which due to electrostatic induction the top part of electroscope gets positively charged while the leaves of electroscope become negatively charged. Now if we Earth the positively charged end of electroscope as shown in step 2, then electrons must flow from Earth to...
  27. A

    B Can you create neutronium by colliding electrons and protons?

    Suppose in a Vacuum with no external influences we have two particle accelerators pointed at each other. They're maximally precise and one fires an electron while another fires a proton. Both the electron and proton have the same amount of momentum such that their x-axis velocity completely...
  28. E

    I How does diffusion of high energy electrons shift band structure?

    When an n-type material comes in contact with a p-type material to form pn-junction, electrons with the highest energy in the conduction band will diffuse to the p-side to reach equilibrium so the entire band structure on n-side will shift down relative to p-side as described in the following...
  29. N

    B Electrons & Photons: Are They Tiny Gaseous Planets?

    I am not sure if this is the way to ask questions here but having nobody to ask and little time, i hope i can get a fast reply here. So since the scaler the universe above us i.e. bigger than us is so huge and we aren't even sure about it further than sight (acc to my book), isn't it just...
  30. M

    A Sampling Electrons from a 2D Projection: Is There a Functional Form?

    Hello! I have some electrons produced from a 3D gaussian source isotropically inside a uniform electric field. The electric field guides them towards a position sensitive detector and I end up with an image like the one below (with more electrons on the edge and fewer as you move towards the...
  31. C

    I Is there traction force between moving electrons & copper wire?

    Common sense: walking on road, there is traction between shoes & earth. I'm wondering: same thing for electric current's electrons & copper wire?
  32. V

    Do electrons flow through a battery or is it something else?

    This is a confusing question. I am not sure if electrons flow through the battery from positive terminal to negative terminal against the electric field within the battery; or the electrons deposit on positive plate resulting in a chemical reaction that releases electrons at the negative plate...
  33. Zuzana

    I Electrons from Internal Conversion

    Hi, I would like to ask, why K-shell electrons coming from the internal conversion are much more frequent than L or M-shell electrons (see Fig). K-shell electrons are more tightly bound than L-shell, I would say that it is easier for gamma particle to kick off less tightly electron, no? Thank...
  34. W

    B Are electrons everywhere?

    I am wondering what the public or mainstream scientists think of the statement that electrons being everywhere nowadays. If electrons are everywhere, can we assume space or void is just the totality of electrons?
  35. J

    Find the resistance of electrons in nanoshells

    We are given the resistivity of Gold. The length will be the outer radius minus the inner radius. We need to find the area. But I'm not sure how that would work given the spherical nature of the particle Would we need to use an integral to add up the increasing cross sectional area from the...
  36. J

    Find the drift speed of electrons in a wire

    We need to find each variable. ##I## is already given to us as 8 amps. The charge of an electron is 1.6 x 10^-19 coulombs. The cross sectional area will just be ##\pi(1.2∗10^−3)^2## m^2. Now we need to find the free electron density. We are given the density of of copper and can use dimensional...
  37. Neo Tran

    The occupation probabilities of electrons in different states

    occup is proportional to [gi x exp(-Ei/kT)] where gi is the numver of states at energy Ei
  38. physicks885

    Minimum seperation of two electrons moving toward each other

    [Mentor Note -- Two threads started by partners in a class have been merged into this one thread, since they are working on a shared solution to turn in]
  39. Dario56

    I Kinetic Energy and Potential Energy of Electrons

    Time indepedendent Schrödinger equation for a system (atom or molecule) consisting of N electrons can be written as (with applying Born - Oppenheimer approximation): $$ [(\sum_{i=1}^N - \frac {h^2} {2m} \nabla _i ^2) + \sum_{i=1}^N V(r_i) + \sum_{i < j}^N U(r_i,r_j)] \Psi = E \Psi $$ Terms in...
  40. H

    Electrons and their little role in nuclear physics

    In this thread, @haruspex presented a very deliberate point about the role of electrons in a nuclear fission reaction (he might have said or meant something else but I will present my version of it). The problem that we have before us can be stated, as candidly as my linguistic faculty of mind...
  41. D

    I Behaviour of electrons in a teltron tube

    If I switch off the anode voltage in a teltron tube (used to determine the charge-to-mass-ratio of the electron), the visible electron beam disappears. Why is this so? The electrons, which were already shot out of the electron gun before, have a high velocity and should continue to move on a...
  42. John Mohr

    B Does a DC Cell or Battery Actually Supply Electrons?

    I have held the assumption that batteries supply electrons at the negative terminal and absorb electrons at the positive end for many years. However, after watching this video at about 3:30, it is said that batteries do not actually supply charged particles but that the battery only creates an...
  43. D

    Lessons with electron beam deflection tube and teltron tube

    Hello, I would like to discuss with my students the deflection of electrons in electric and magnetic fields. For this purpose, I would like to perform the experiments with electron beam deflection tubes and teltron tubes. How would you implement this organizationally in the classroom? There are...
  44. D

    B Quarks, electrons, neutrinos, and photons?

    Can someone please explain the four classes of fundamental particles? (Just the basics) I came here because I never learned any chem or physics in school so please explain like I’m five :)
  45. Green dwarf

    I Virtual Photons: The Long-Distance Repulsion of Electrons

    My understanding is that the repulsion between two electrons is mediated by the exchange of virtual photons – virtual meaning not lasting long enough to be detected. But suppose one of the electrons is in the sun and the other on Earth. There should still be a repulsion because the...
  46. ktmsud

    I Continuous Spectrum and Energy levels of Electrons (Energy Bands)

    My book says that emission spectra are produced when an electron in excited state jump from excited to lower energy states. It also states that solids and liquids produce continuous spectra and it depends upon temperature only (is this black body radiation?). I know, Electrons around a nucleus...
  47. S

    I Do electrons flow in an electrical circuit?

    The video on youtube on the above link seems to imply that electrons don't flow through a circuit. At 01:29 into the video, the narrator says that he used to teach his classes how electrons move through a circuit by using a clear plastic tube with a chain inside of the clear plastic tube. The...
  48. S

    I Are all electrons identical?

    I'm just confused on whether not all electrons are identical and if they are, how they are.
  49. 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...
  50. 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...