Electron Definition and 999 Threads

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. bburke95

    Find Electron Current Through Iron Wire

    Homework Statement What electron current is driven through a 1.4-mm-diameter iron wire by a 0.070 V/m electric field? The mean time between collisions in iron is 5.2×10^−15s . A=1.5*10^-6 m^2 ne=8.5*10^28 m^-3 Homework Equations I know I need to use ie = neAVd, but I'm having trouble finding...
  2. N

    Do electrons have kinetic energy in an electrical circuit?

    I got a question towards kinetic energy and elektrical energy. They always talk about about particle accelerators or devices when talking about transformation of elektrical energy into kinetic energy of elektrons. But do elektrons also have kinetic energy when they are circulating in an...
  3. C

    A Accelerating an electron in beta decay

    The electron created and emitted in the beta decay of a proton has an initial velocity close to the speed of light. When I try to calculate, not taking into account relativity, the force needed to accelerate an electron to that velocity over a distance the size of a proton, I get about 45 N...
  4. kiwaho

    I Can electron beam accelerate electron capture beta decay?

    Some nuclides undergo decay of electron capture or beta plus. Can electron beam with appropriate energy accelerate electron capture beta decay? Same scenario: If I am looking for something, and my friend kindly hands it over to me, then I say thanks, because my seeking time is shorten.
  5. A

    Hydrogen Electron Transitions (Allowed/Forbidden)

    Homework Statement Determine if the electron transitions are "allowed" or "forbidden" using the transition rules: i. 2p→2s ii. 1s→2p iii. 3d→2p iv. 3d→1s v. 4s→2p Homework Equations Δl = ±1, Δml= 0, ±1 E = (-2.18*10-18eV)(1/n12 - 1/n22) The Attempt at a Solution I know iv. is forbidden...
  6. M

    Smashing Electrons: What Would Happen?

    I have heard of many experiments dealing with smashing protons or neutrons, but I've never heard of smashing electrons together! What would be the result of such experiment?
  7. P

    A Magnetocaloric effect and electron energy levels

    i am trying to understand the magnetocaloric effect from another point of view (besides thermodynamics ) , i know that under the influence of an external field , a zeeman splitting happens , and the electrons will have different levels of energy , those with + 1/2 spin will have a higher energy...
  8. bachfromthedead

    Finding the deBroglie wavelength: conceptual issue

    Hello all! I am new to this forum, though I have been lurking for a long time. I intend to fill out my profile and introduce myself, but finals leave me with little time to spare at the moment. I have this final next week and would like to sort this out beforehand, hence the hasty post! Thank...
  9. Giorgi1997

    Photon colliding with moving electron

    Homework Statement Consider Comton scattering of a photon by a moving electron. Before the collision the photon has wave length λ and is moving in the +x direction, and the electron is moving in the -x direction with total energy E. The photon and electron collide head-on. After the collision...
  10. J

    A Computing the resistivity due to electron collision with 1BZ

    Hello there, Id like to estimate how the resistivity due to electron 'collision' with 1st Brillouin zone changes as a function of number of valence electrons in a metal. Say you start with Na, then add some other material with 2 valence electrons instead of 1, then the fermi wavevector will...
  11. Kevin McHugh

    Exploring the Phenomenon of Electron Volt: Mass, Temperature, and Energy

    The electron volt can be defined as mass, temp and energy. 1 eV = 1.6022 x 10-19J 1 eV = 1.783 x 10-36kg 1 eV= 1.160 x 104K How can something with such small energy and mass exhibit such high temperature? 104K is white hot
  12. D

    I Determination of electron energy in the 2 slit experiment

    If w3e fire electrons thru the 2 slit we get an interference pattern showing the wave nature of the electron. Now if we cover one of the slits and fire electrons we get a bar like pattern on the screen. If we cover one slit, fire electrons and use a detector we would also get a bar like...
  13. vetgirl1990

    Compton effect: Scattering angle of electron

    Homework Statement A 0.7MeV (E°) photon scatters off a free electron such that the scattering angle of the photon is twice the scattering angle of the electron (θ=2φ). Determine the scattering angle for the electron. Homework Equations λ' - λ° = h/(mec)(1-cosθ) E = hc/λ ρelectron = mev /...
  14. MullaTheMech

    Difference Between an Electron and a Positron?

    [Mentor's Note: The first 4 posts have been split off from another thread.] I want to know why a electron has a different charge than a positron. lets use an electron and positron that came to be at the same time and place. They should have split something. Can someone explain what it is they...
  15. kiwaho

    I Is there way to thermalize an electron to room temperature?

    At room temperature, particle energy is 0.025eV. Neutron capture reaction has big cross section when neutron is in room temperature. Theoretically, so does an electron. At 0.025eV, the electron velocity should be only 93.78km/s. Unfortunately almost no way to cool down an free electron to so...
  16. Arubi Bushlee

    B How Do Electron Orbitals Work at Relativistic Speeds?

    So I was wondering... for no particular reason: Say you have a proton and your right arm is a particle accelerator. You throw the proton at about 90% the speed o' light. The you take your left arm which also happens to be a particle accelerator and you shoot an electron out right next to it...
  17. S

    Optimizing PMT Circuit: Resistor Values for Secondary Electron Detection in SEM

    Hello, I have a 12 pin Photomultiplier tube and am wondering how many ohms should be on the resistors. There would be 11 resistors (1 between each pin) and no capacitors, anode grounding for DC operation, 1000volts, only to go off to an op amp for signal processing. This design is shown in...
  18. ReidMerrill

    Coordination Chemistry and d electron numbers

    Homework Statement Predict the number of unpaired electrons [Cr(H2O)6]3+ Homework EquationsThe Attempt at a Solution I under stand how to fill out the MO with the eg and t2g and all but I'm confused about determining the number of electrons. The answers state this is an octahedral d3 but I...
  19. newjerseyrunner

    B What's an electron doing between interactions?

    I know an electron is constantly flipping between two quantum spin states. I know that one spin takes slightly more energy than the other and it gets and drops this energy into and from the Higgs field, which gives it mass. The default behavior of all particles is to travel at the speed of...
  20. S

    Why doesn't an electron lose energy between components?

    I understand that in an electrical circuit, a positive test charge will gain electrical potential energy when moving from the negative to positive terminal of a battery (as it's moving against the electric field); it will then naturally flow around the circuit back to the negative terminal as it...
  21. kenyanchemist

    Probability distribution curve for an electron in 2s and 2p

    hi, so my lecturer decides to give me manic depression by sending me on a wild goose chase. what is the general form of a plot of Ψ, Ψr2 and r2Ψ versus r for both Ψ2s and Ψ2p orbital... am not even sure i said it right So far I have only gotten the Ψ2r2 versus r
  22. A

    Electron movement in conductors

    This is not a normal problem help topic. The difficulty I've encountered is in understanding an alternative solution. 1. Homework Statement In a real conductor, electrons (with mass m), conducted by external electric fields, constantly collide with defects and impurities within the conductor...
  23. StanEvans

    I Neutron Star Formation: Quarks, Protons, Electrons Explained

    So a programme that I watched on tv was talking about neutron stars and they said that the neutron stars neutrons were formed by protons and electrons combining to make neutrons. I was just wondering, how does this work, in the field of the quarks in the proton and how they are effected by an...
  24. H

    Does an electron beam bending lose energy by photon emission

    A beam of electron in vacuum with velocity v enter a region of spa e with a electric field E. The field is such the electrons circle with radius r. The electrons are now accelerating at constant tangential speed. Because this is not an atomic orbital then by classical physics the electrons...
  25. G

    B Electron arrangement and ionisation energy

    Why is it easier to remove an electron from p orbital than s orbital. I thought P orbital have higher energy so more energy is require to remove a electron from P orbital.
  26. Docscientist

    Why can't electron be stationary ?

    What do we mean when we say the energy of electron in stationary state is given by an equation from bohr's model of hydrogen atom ?
  27. Docscientist

    Exploring the Invariance of Electron Energy over Time

    Why does the energy of an electron does not change with time ?
  28. Oaxaca

    B DeBroglie Wavelength with Relativistic Electron

    I am trying to find the DeBroglie wavelength of an electron moving at .8c. I have never learned special relativity but I believe the momentum is affected (mass change). I used the formula p= (mv)/(1-v^2/c^2) and got a momentum of p = 2.733 E-22 and a wavelength of lamda = 2.4149 E-12. Did I...
  29. thecourtholio

    Electron Configuration/Hund's Rule/LS Coupling

    Homework Statement Consider the electronic configurations [Ar]3d94s1 and [Ar]3d10 for an atom. (a) Identify this element. (b) Use Hund’s rules to explain which is the ground state. Show your work for full credit. Homework Equations J=L+S n2S+1LJ L= l1+l2 S= s1 + s2 or S = (1\2)* number of...
  30. Icy98

    Movement of electron in an electric field

    Homework Statement An electron has an initial velocity of 5.00 x 10^6 m/s in a uniform 2.00 x 10^5 N/C strength electric field. The field accelerates the electron in the direction opposite to its initial velocity. (a) What is the direction of the electric field? (b) How far does the electron...
  31. M

    Electron Properties: Electric vs Magnetic Fields

    We can deflect a moving electron using an electric field or using a magnetic field. In order to obtain the same deviation, when the energy we should use is higher? Or, in other words, the "electric" or the "magnetic" property is stronger?
  32. P

    I Basic band theory question, free electron model

    Hello, I am trying to figure out the width of bands in a 1-dimensional lattice. Here is a short derivation from the book I am reading: if we approximate the free electrons as being in a square well then the energy levels are ## \frac{\pi^2 \hbar^2 n^2}{2mL^2}##. If there are ##N## ions...
  33. P

    Electron in a Finite Square Well

    Homework Statement An electron in a finite square well has 6 distinct energy levels. If the finite square well is 10nm long determine: a) Approximate the possible values for the depth of the finite square well ##V_0##. b) Using a well depth value in the middle of the results obtained from part...
  34. S

    I Can an electron in an s-orbital exist at the nucleus (r=0)?

    My quantum textbook says that the probability of finding an electron in a 1s orbital between r and r+dr is given by Prob = (4/a^3)*(r^2)*exp(-2r/a) dr. In this case, Prob(0) = 0 because of the r^2, which is part of the volume element in spherical polar. Does this mean that it is impossible to...
  35. Ryaners

    Electron in 1-D box: photon absorbed?

    I don't know where I'm going wrong with this problem - I was so sure I had it right but the online grader tells me otherwise :oldfrown: Homework Statement An electron in a one-dimensional box has ground-state energy 2.60 eV. What is the wavelength of the photon absorbed when the electron...
  36. B

    Rms velocity of electron in free space?

    Homework Statement How many orders of magnitude smaller is the average drift velocity of a hole than the RMS thermal velocity of an electron moving in free space? (Use the law of equipartition to find the RMS thermal velocity of a free electron.) This is the last part of the problem, I have...
  37. nilesh_pat

    About atom's image in electron microscope

    In Hydrogen atom, in center Proton and Electron revolving it. My question, is that enclosed in a cell, actually what we see in electron microscope. Regards Nilesh
  38. T

    I Why electron enters the lowest potential possible?

    Why electron and overall an atom is most stable in lowest potential energy? There is a concept of stable equilibrium in classical physics, does it apply here as well? but electron is never in an equilibrium state, neither an atom is. Then why it tries to be in lowest potential?
  39. R

    Special Relativity problem -- An electron travels at 0.422c....

    Homework Statement An electron travels at 0.422c. Calculate the following. (a) the relativistic momentum kg · m/s (b) the relativistic kinetic energy J (c) the rest mass energy...
  40. W

    Compton Scattering; Relation between scattering angles

    Homework Statement Show that the scatter angles of the photon (θ) and electron (Φ) in the Compton effect are related by the relation: ##cot (θ/2 )=(1+\frac{hf}{mοC^2}) tan(Φ) ## Where f is the frequency of incident photon 2. The attempt at a solution I wrote down the equations of conservation...
  41. BiGyElLoWhAt

    I Understanding Electron Spin: Deep Theoretical Reasons Explained

    This has always bugged me, but it appears that the answer is out there via this: "But deep theoretical reasons having to do with the rotational symmetry of nature lead to the existence of spins for elementary objects and to their quantization." The sentence before says this: "A simple answer...
  42. M

    I Can an Electron Absorb a Photon if the Next Energy Level is Full?

    Can an electron absorb a photon and jump to a higher orbit if the next level is already full of electrons? please explain what happens and also link info that might help me with electron/ photon interaction. I have many questions. Thanks
  43. Nick tringali

    What happens when an electron and a positron meet?

    The question also wants a numerical answer, calculate the amount of energy released. I am helping my friend with this because she is bad at science, but she is in College. If anyone knows of any formulas that would be of use, i would appreciate it.
  44. yango_17

    Electron in a box - wavelength of photon

    Homework Statement a) An electron is trapped in a one-dimensional box that is 526 nm wide. Initially, it is in the n=2 energy level, but after a photon is absorbed the electron is in the n=7 energy level. What is the wavelength of absorbed photon? b) Eventually, the electron ends up in the...
  45. P

    At any given instant, how fast might an electron be moving?

    Homework Statement This is problem 5-42 from Modern Physics by Tipler & Llewellyn. Neutrons and protons in atomic nuclei are confined within a region whose diameter is is about ##10^{-15}##m. At any given instant, how fast might an individual proton or neutron be moving? Homework Equations 3...
  46. P

    Excitation of a hydrogen atom by electron collisions

    The problem: A beam of electrons with kinetic energy 12.8 eV collides with a hydrogen target. What visible spectral lines will be emitted due to collisions? My question: I am confident I know how to do the bulk of this question, I am just uncertain about one thing: I know that 12.8 eV is enough...
  47. I

    How do I solve an electron density continuity equation for Earth's atmosphere?

    Homework Statement Hi! I need to solve a continuity equation for electron density as a function of time in the E-region of Earth's atmosphere. I shall neglect vertical transport and that the ion production rate completely shuts off dusk. Homework Equations See below The Attempt at a...
  48. H

    Are Electron Orbitals Always Spherical in Shape?

    The probability distribution of the position of the electron of a hydrogen atom is related to the following polar plots Suppose the electron is excited from the ##1s## orbital to the ##2p_x## orbital. Does it make sense to talk about the ##2p_x## orbital having a dumbbell shape pointing in...
  49. samjohnny

    Electron Configuration of Excited State

    Homework Statement An exercise examining the tin atom (Sn). Tin has a ground state electron configuration of ##[Kr]4d^{10}5s^25p^2##. a) Write down the electronic configuration of the first excited state. b) Illustrate with a vector diagram the allowed total angular momentum ##J## values for...
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