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. J

    Do electrons only feel the electric field?

    Do electrons only "feel" the electric field? Imagine that you're an electron. You are always at rest in your inertial frame so that you do not "feel" the \mathbf{v} \times \mathbf{B} term of the Lorentz force. Thus, from your perspective, you only ever "feel" an electric field...
  2. ajayguhan

    Understanding Ion and Electron Flow in Galvanic and Electrolytic Cells

    I know that positively charged cation move toward cathode which is the negative terminal and the negatively charged anion move towards anode which is positive terminal Why does in galvanic cell cations are moving toward cathode which is positively terminal? And why in galvanic cell...
  3. T

    Determining the maximum number of minority electrons in semiconductor

    Homework Statement P-type silicon can be doped in the range from 5x1014 cm-3 to 1020 cm-3. Determine the maximum possible number of minority electrons in a neutral P-type region if the device area is limited to AD = 1 cm x 1 cm and the thickness of the P-type region is limited to tP=100 μm...
  4. O

    Can Virtual Electrons Really Just Pop in and Out of Existence?

    I am not sure if this is the right place to post this, so please let me know...? If electrons pop in and out of existence, how does that relate to the law of the conservation of matter? The electrons can't just disappear. Are the electrons just visiting the other element in the molecule? Like...
  5. M

    Why do electrons with orbitals farther from the nucleus have greater e

    If the electrons closer to the nucleus experience greater electrostatic attraction from the nucleus, would not the closer electrons require more energy to stay in orbit? Also, the electron shielding from the inner electrons would reduce the energy required to stay farther away from the nucleus...
  6. G

    Can someone explain the diffraction of electrons through a single hole?

    Could anyone please explain the mechanism of diffraction of electrons through the single hole. Have a look on the picture attached. It says if we would shoot only one electron at a time, the pattern would be the same. Things which are confusing me: 1. If the source of emitted electrons is far...
  7. Enigman

    Probability of finding electrons in nucleus (s orbitals)

    Why is the probability of finding an electron of s orbital in the nucleus highest? Is Quantum Tunneling involved? If so, won't the electron need a large amount of energy to pass through the nucleus?
  8. J

    How Many Excess Electrons Does a Negatively Charged Balloon Have?

    Homework Statement A negatively charge balloon has 2.4 μC of charge. How many excess electrons are on this balloon? The elemental charge is 1.6e-19 C. Answer in units of electrons. The attempt at a solution I keep getting 1.5e13 electrons but the system is telling me it's wrong. I put it in...
  9. M

    Webpage title: Understanding the Direction of Electron Flow in Circuits

    In the paint document you will see on the LHS a picture of a circuit diagram then on the RHS you will see a pictorial representation of an electron in the circuit located at an arbitrary point My question (which is in the paint document): I want to know why the electrons flow in the direction...
  10. B

    Do electrons push each other in a circuit ?

    i have a made a thread a few hours ago with something related to this but i would like to know do electrons push each other in a circuit ? that would explain the constant intensity across a circuit before electrons even reach a resistor . i mean they push each other like some kind of...
  11. T

    What is the Fraction of Electrons Removed from a Charged Ball of Copper?

    Homework Statement A 48.7 g ball of copper has a net charge of 2.2 µC. What fraction of the copper's electrons have been removed? (Each copper atom has 29 protons, and copper has an atomic mass of 63.5.). Homework Equations The Attempt at a Solution Number of electrons normally present ...
  12. H

    Thermal excitation of electrons in semiconductors

    Which mechanism in semiconductors is responsible for electron excitation from valence to conduction band in thermal equilibrium at temperature T? Do valence electrons take their excitation energy from the lattice by absorbing phonon? If so, they can be excited at each arbitrary temperature no...
  13. K

    8 Electrons in a 3-D Infinite Square Well w/ Spin

    Homework Statement A cubical box whose sides are length L contains eight electrons. As a multiple of $$\frac{h^2}{2mL^2}$$ what is the energy of the ground state of the eight electrons? Assume the electrons do not interact with each other but do not neglect spin. Homework Equations...
  14. S

    Do electrons (in a shell) have to be necessarily entangled?

    Are electrons in the, say lowest energy level, shell, of an atom, always entangled? i.e. Do electrons (in a shell) have to be necessarily entangled? Is there any maths (law of conservation of spin/momentum etc) that says so? Any relation with Pauli's exclusion principle?
  15. shounakbhatta

    Valency electrons and determining the spin

    Hello, I need to understand the following: Considering an element Sulfur - S which has 16 electrons. How do we calculate the valency electron of S? Please correct me if I am wrong:2+2+6+2+4=16. So, the valency electron = 4+2=6 Is it that always valency electron is the addition of...
  16. O

    Find n for Reaction Equations: General Method

    how can the number of electrons, n, in a reaction equation be found generally? for example: Tl3+ + 4I– → TlI4– I2(s) + I–(aq) → I3–(aq) Tl+ + I3- → Tl3+ + 3I- How to work out standard electrode potential from K or vice versa depends on value of n. for these 3 I know they are n=1, n=2 and...
  17. H

    Exchange energy of electrons in degenerate orbitals

    We are taught that a reason for the stability of half filled or fully filled orbitals is due to the high exchange energy. Now i get why the exchange energy would be higher compared to other configurations but i don't understand why electrons present in degenerate orbitals would want to exchange...
  18. A

    Exploring the Diffused State of Electrons Around Nuclei

    An electron doesn't move in an orbit round the nucleus. It is in a diffused state. Please explain what is the meaning of this statement and what is diffused state.
  19. J

    Electrons: Questions about observations, semantics & concepts

    I've been puzzling over things I've read about quantum physics as it relates to reports of things "seen" and the nature of the concepts/semantics/assumptions involved. If this sounds vague its because my thoughts are not fully formed on this. Some detail: In a new article titled: "Physicists...
  20. A

    The Wave-Like Nature of Electrons: Electric & Magnetic Fields

    when we say , electron acts like a wave ,does we mean to say that it produces electric and magnetic field or em waves varying with distance and time
  21. 7

    What happens when we rotate crystal while shooting electrons at it?

    I know that if we shoot narrow beam of electrons at the crystal (we don't change the angle) we will get a diffraction of electrons according to the brag's law. Therefore we get minimums and maximums on the screen around the crystal. Until now we have been dealing with problems where...
  22. L

    Electrons Absorbing Photons - Extra Energy

    Okay, so when a photon travels near an electron orbiting some atom, the electron then absorbs the photon (given that it has enough energy) and causes the electron to jump up an energy level. My question is what happens when a photon has a little more than enough energy to bump up the electron...
  23. C

    Relativistic Treatment of Core Electrons (DFT)

    I realize this is something I should probably know intuitively, but why are core states (generally) treated relativistically in density functional calculations? What exactly makes these relativistic bound states rather than non-relativistic? I think this is some basic physics I'm forgetting.
  24. S

    Migration Path of Electrons in Ionized Air (Gamma Radiation)

    I would love some clarification on a gamma ray process. This is what I understand so far: Electrons are accelerated at 19MeV at a cathode which is releasing gamma ray photons with an energy of 1.9MeV. Is it possible to generalize the emission number of photons (roughly) to be equal to the...
  25. M

    Electrons when their spin changes for hybridization?

    Forgive me in advance if this appears to be a dumb question but, as I was reviewing a few basic chemistry topics, namely orbital hybridization, I came across a question. From what I gather, according to Hund's Rule, an electron must be put into all open orbitals before the remaining orbitals can...
  26. ikihi

    Valence Electrons of ClO2+: A Comprehensive Guide

    1. Homework Statement ClO2+ ion: A. How many total valance electrons does this ion have? B. Which atom is the central atom? C. How many bonding electrons are there between the central atom and each of the other atoms? D. How many nonbonding electrons are there on the central atom? 2...
  27. ikihi

    How Many Valence Electrons Are in the ClO2+ Ion?

    Homework Statement Use a piece of scratch paper to draw the Lewis structure for the ClO2+ ion, and then answer these questions (be sure to answer all of them): A. How many total valance electrons does this ion have? B. Which atom is the central atom? C. How many bonding electrons are...
  28. P

    Question about flow of electrons along wire.

    I know that electrons flow across the wire from the source to the receiver, but would it be possible to keep these electrons on the wire after disconnecting the source and receiver?
  29. S

    Protons and electrons. Propulsion.

    I've had this strange theory for a long time. If a free floating proton has a tiny amount of mass, wouldn't excelating it to near C increase its mass or energy nearly infinitely? If this is so, if we run a wire and fire electrons down its length let's say 100 times per second. Then fire...
  30. V

    How protons electrons and neutrons relate to an atom's characteristics

    So i was wondering if perhaps a atoms electrons protons and neutrons determine all of its characteristics, such as the hydrogen atom. having only one electron and one proton. it makes it turn into a liquid and solid very close together, and a gas anything above about -259.1°C. and the...
  31. O

    Electrons causing nuclear decay

    Hello everybody, I am a first year and I have one more question. To what degree do electron contribute to nuclear decay? (Do electron which can 'spend' some time in the nucleus cause bigger decay?) Thanks in advance :)
  32. Saitama

    Understanding the Motion of Electrons in a Magnetic Field

    Homework Statement Homework Equations The Attempt at a Solution Let magnetic field be inside the plane of sheet (towards -ve z-axis) At any instant of time, let the components of velocity of electron be ##v_x## and ##v_y##. Then ##F_x=ev_yB_o## (i) and ##F_y=-ev_xB_o## (ii)...
  33. A

    Is it possible electrons fallen into holes and go straight to collecto

    I took this picture from forum aboutcircuits to illustrate current flow in NPN transistor. Here is what I am confused: A few at Figure above(a) fall into holes in the base that contributes to base current flow to the (+) battery terminal. Why these electrons that fall into holes necessary...
  34. K

    Help with understanding of magnetic fields related to moving electrons

    Hello all, I am in need of understanding of magnetic fields. More specifically i was wondering exactly why there is a magnetic field around a wire with current moving through it. Where i am going with this is.. if i had plasma contained, and i managed to get it moving in the container, would...
  35. M

    Ground configuration of Equivalent electrons

    It is the procedure you do to get ground term symbol in LS coupling. What is meant by this "ground term"? As in a physical meaning. If you don't know the procedure it is in this link: http://en.m.wikipedia.org/wiki/Term_symbol, please seek "Ground State Term Symbol" Section.
  36. S

    Spin of electrons within (x,y,z) 2P orbitals

    Question. Is there a quantum reason why a lone electron in any of the three available (x,y,z) 2P orbital energy states must always be spin-up or spin-down ? Every figure I see always shows a single electron as spin-up for the three 2P energy states, but is there a quantum theory constraint...
  37. ShayanJ

    Exploring 'Cold' Electrons & Plasma Oscillations

    In some texts about plasmas, the plasma oscillations are discussed at the extreme of no Thermal motion. One example is the one in wikipedia: But I can't accept that approximation.Because it is assuming that we have a kind of motion called thermal motion and other kinds which arise from other...
  38. S

    Outer valence electrons for d-block elements (Se to Zn)

    I wish to better understand the configuration situation for the outer most valence electrons for the d-block elements, Sc to Zn. I am having a problem understanding how to predict where the two outer most valence electrons must be located for some of the ten d-block elements? For some...
  39. lonewolf219

    Are wavefunctions specifically describing electrons?

    Hello, Wave functions and energy levels... What particles are being described by Schrodinger's equation? If we are talking about energy levels, do we mean the energy levels in an atom? Other particles, such as electrons or quarks... do they have energy levels, or are they too small for us to...
  40. Q_Goest

    Why don't electrons flow between batteries when not connected?

    Let's say you have 2 batteries, both 1.5 V. If you put your red voltmeter lead on the + of one battery and your black voltmeter lead on the - of the other battery, and assuming the two batteries are not touching, the voltage you read is zero. I know this is a simple question, but why? Why don't...
  41. K

    Runaway Electrons in Magnetic Fusion - Benefit/Cost & Energy Extraction

    Was reading about runaway electrons in magnetic fusion. Had me thinking what would be the benefit/cost of engineering a device which creates a beam of reletivistic electrons. What would be the best way to extract energy from this system and does it even matter the speed they are traveling?
  42. G

    Do electrons need specific energies to excite electrons

    Photons need specific energy levels, equal to the difference between two energy levels to excite an electron in an atom. Is this the same case with electrons that collide with atoms?
  43. Z

    Electrons viewed in real time for the first time ever

    From the article: This is one of the first direct applications of attosecond pulses, but according to Berkeley researcher Stephen Leone, this is just the tip of the iceberg for what the technology can do. http://io9.com/5605687/electrons-viewed-in-real-time-for-the-first-time-ever Comment...
  44. D

    Are electrons constantly orbiting around the nucleus in an atom?

    Homework Statement Hi,I am currently studying A-level physics in the UK.:smile: I have been taught that electrons in an atom are orbiting around the nucleus. I would like to ask a question: Consider 2 situations: (1): A man is pushing a box forwards along a horizontal road. Work done...
  45. S

    Magnetism; the path of electrons

    The path of electrons emerging grom an accelerator must be bent by 90° by a 'bending magnet' so as not to strike a barrier in their path a distance d from their exit hole in the accelerator. Show that the field B in de bending magnet, which we assume is uniform and can extend over an area d*d...
  46. T

    Can Adding an Electron Change the Properties of a Hydrogen Atom?

    If you stuck 1 electron into the inner shell of a hydrogen atom, would the properties change? Thanks all, Joe.
  47. T

    Why Can Electrons in the Conduction Band Move Around so Easily

    As my title states, I want to understand why electrons in the conduction band can move around so easily in the material. Is it due to the presence of many closely spaced (blurred out) energy levels which make it easy for the electrons to move around? Or are the electrons undergoing some kind...
  48. V

    Proof of maximum no. of electrons in a shell

    how do you prove that the maximum no. of electrons in the nth shell of an atom is twice of n squared (2n^2)
  49. K

    Photons and electrons and electricity.

    A) I want to understand electricity in terms of quantum theory. as I understand photons are the carriers of EM energy so how do photons trasfer energy from electric company or battery through a wire. and the connection to electron movement (do electrons from one atom bum into another...
  50. jaumzaum

    Why electrons can have only 2 spin orientations?

    I'm studying electron spin/magnetic field and I was taught electrons can have only 2 spin orientations, as seen in the Stern and Gerlach experiment. But this orientations are given in relation to what? Do all electrons in the universe have the only 2 same orientations, or only the electron in...
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