What is Electron: 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

    Quantum Book on quantum electrodynamics

    Can anyone suggest me a book on quantum electrodynamics for beginners? Thanks in advance
  2. 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...
  3. 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...
  4. 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.
  5. 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 ?
  6. Docscientist

    Exploring the Invariance of Electron Energy over Time

    Why does the energy of an electron does not change with time ?
  7. 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...
  8. 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...
  9. 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...
  10. 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?
  11. 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...
  12. 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...
  13. 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...
  14. 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...
  15. 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...
  16. 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
  17. 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?
  18. 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...
  19. 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...
  20. 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...
  21. M

    I Photon absorption by electron

    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
  22. 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.
  23. 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...
  24. 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...
  25. 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...
  26. 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...
  27. 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...
  28. 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...
  29. Anonymous Vegetable

    What is the force responsible for bonding between atoms in a covalent molecule?

    In a covalent bonded molecule, what is the force responsible for the molecule staying together. To my knowledge it's to do with electrons of opposite spins and being at a lower energy with valence shells filled but what is the force itself that pulls a second atom along if the atom it's bonded...
  30. T

    What happens when an electron is hit by a laser beam?

    Just a quick question. We know that an accelerated electron shoots out light, and light that falls on an electron in an atom, excites it. But what happens to an electron in vaccum, when it encounters a laser beam? If an electron beam from an electron microscope, were to to intercept a laser...
  31. D

    Kinetic Energy of neutron and electron

    Question in my textbook:- The wavelength of light from the spectral emmision line of sodium is 589 nm. Find the kinetic energies of electron and neutron at which they both have same de broglie wavelength. Logically, since light of same energy is falling on both then their kinetic energies must...
  32. C

    Nanoscale propulsion system that works in vacuum - or not?

    Moved this question from the quantum physics section to this section, since... Well it fits this section better since electrons apparently do obey conservation of momentum in the 'classical' sense. Why not produce thrust in microgravity with electrons? Plenty of harnessable electricity in...
  33. C

    Does Conservation of Momentum Apply to Electron/Atom Interactions?

    Electrons have a theoretical rest mass. They can move at varying speeds through space, unlike photons. They ehxhibit quantum-characteristics in their behavior. If an electron collides with, say, an atom, does conservation of momentum apply in the classical sense or does measurable mass (an atom...
  34. U

    At what scale is the charge of an electron -2e?

    The charge of an electron is -e in energy scales well into the atomic scale. At infinitesimal scales it becomes infinite. This relation must be continuous for re-normalization to work, thus the intermediate value theorem asserts that it attains all values between at some energy level. I want to...
  35. R

    Why does an electron create a magnetic field when it moves?

    i am just a student who wishes to learn more about physics and the way the universe works, but because i am 14 and am just starting to learn all of this on my own i have to start from scratch, please present me with any usable information
  36. Telemachus

    Nearly free electron model: band gap

    I was trying to determine the bandgap in the nearly free electron model. I'm having trouble to determine the band gap bewteen the second and the third band. Its a one dimensional problem. So, the central equation reads: ##\displaystyle \left [ \frac{\hbar}{2m} (k-G)^2-E \right ]c_{k-G}+...
  37. D

    Electron Capture: Explaining Too Many Neutrons

    Homework Statement My book is saying that if a nucleus has too many neutrons beta minus decay or electron capture is going to happen. The nucleus wants to get rid of a neutron so it is going to send out one electron and an antineutrino that originally comes from the neutron. But what I don't...
  38. G

    Energy of scattering photon and emitted electron

    Homework Statement Photon of energy E=0,3MeV is scattering at an angle \phi=\frac{2\pi}{3}. Calculate the energy E' of scattered photon and emitted electron. Homework Equations -Compton effect The Attempt at a Solution By Compton effect...
  39. henrco

    What is the radius of the orbit of an electron

    Hi All, Having difficultly figuring out where I've gone wrong with this problem. Any guidance gratefully received. 1. Homework Statement A 4.76 keV electron (an electron that has a kinetic energy equal to 4.76 keV) moves in a circular orbit that is perpendicular to a magnetic field of 0.392...
  40. I

    Electron density as a function of time

    Homework Statement Hi! I really need help with finding time- dependent continuity equation for electron densities in the atmosphere. I've tried to solve it without any success. My question is if someone can give me a good link/link or equations that I can start with. Homework Equations See...
  41. L

    What is the wavelength of an electron of 5eV energy?

    Homework Statement Calculate the wavelength of an electron which has 5eV of energy.Homework Equations de Broglie's equation: lambda=h/p , kinetic energy equation: K=0.5mv^2 The Attempt at a Solution My attempt: I figured out that using de Broglie's wavelength equation was necessary for this...
  42. neilparker62

    Why Does the Proton-Electron Mass Ratio Diverge from Direct Division?

    In the CODATA table of physical constants, there are very precise numbers given for mass of electron and mass of proton. And an even more precise number for proton electron mass ratio. But when you divide the mass of proton by the mass of electron, you don't get the same number as the proton...
  43. kiwaho

    Can a powerful projectile electron drill through nucleus?

    For example, a cosmic electron projectile at 1TeV, is it possible to fly through a nucleus just like a bullet drills through a cake and makes the cake insensible recoil? After drill-trough, the electron may have some deviation from incident direction because the route may not exactly pass the...
  44. ognik

    Particle Velocity: Speed for 1m Wavelength?

    Homework Statement To what velocity would an electron (neutron) have to be slowed down, if its wavelength is to be I meter? Are matter waves of macroscopic dimensions a real possibility? 2. Homework Equations I have assumed this could apply to pretty much any free particle of mass m, and is...
  45. N

    B If you raise the electron to other higher shell states, can it affect light transmission?

    If you raise the electron to other higher shell states, can light transmission throug -h a SOLID BLACK opaque object. Modified the original question because it was unclear. I won't repeat the same question over, and over, but what I have said in previous questions may get repeated in the...
  46. UchihaClan13

    What Happens to an Electron When it is Excited and Removed from an Atom?

    Okay guys Felt a need to post this since it's been confusing me for a long time Say,for example,we have an atom with its electron occupying the 3s orbital Now let's say we energise the atom and constantly supply it energy that the electron which receives the energy(or a part of it)gets excited...
  47. C

    Electric Potential and Ionization Energy of Bohr Hydrogen

    I was studying for (first year) physics class and was playing around with the Bohr Model of Hydrogen. I tried calculating the electric potential at the Bohr radius r =5.29e-11 m, where V = \frac{e}{4 \pi \epsilon_0 r} (from the point-charge formula for electric potential) and I got 27.19 J/C...
  48. Davephaelon

    Entangled electron in High Temp Superconductors

    I was reading an interview of Dr Subir Sachdev in the latest online issue of Quanta Magazine, and he mentions that Cooper pair electrons in the high temp superconductors (HTSC's) are globally entangled with one another, but in the low temperature (type 1) superconductors, they are not, and I...
  49. P

    Determine electron density with impurites

    Homework Statement Let’s introduce an imaginary atom which can replace the silicon atom and generate one mobile electron. What is electron density when all silicon atoms are replaced by this imaginary atom Homework EquationsThe Attempt at a Solution I have tried looking for a formula to...
  50. P

    Electron Density when Introducing Impurites

    How do you go about calculating electron densities, especially when impurities are involved?
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