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Number of electrons

  1. Apr 9, 2013 #1
    Hi all

    if we cant see an atom, how do we know how many electrons and protons by number it have ?

    please be as detailed as possible
     
  2. jcsd
  3. Apr 9, 2013 #2

    mathman

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  4. Apr 9, 2013 #3
    It seems a fairly typical scientific story.....some interesting physical characteristics noted, models proposed, testing of models, discarding models that don't match observations, new discoveries, new technologies, arguments and disagreements among 'experts', new collaborations, .....eventually, after all the errors have been eliminated, mankind arrives at new insights.....

    Background also here:

    http://en.wikipedia.org/wiki/Atomic_number
     
  5. Apr 9, 2013 #4
    http://en.wikipedia.org/wiki/Proton

    PS: "consensus" has rarely been a final and complete understanding. Often it just means that with the knowledge and testing capabilities available at a particular time, it's the most science can achieve. But it's pretty safe to assume we know the number of protons in a nucleus these days...but just why there are protons at all and why they have the characteristics they do remains a mystery.
     
  6. Apr 9, 2013 #5

    sophiecentaur

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    It has never been.
    The notion that, somewhere, somewhen we will discover some 'absolute truth' is, imo, a delusion.We just find ourselves able to tie more and more loose ends together, as time goes by. This fact does, in no way, lessen the point of scientific investigation, though.
     
  7. Apr 10, 2013 #6
    Well just to add to sophiecentaur I would say that in every way and subcategory in science just as in every other major discipline ever invented there can't be a consensus if there will be more than two men arguing about it , even if we would know everything behind and about everything there still is the opinion or interpretation thing that we humans tend to have just like the air we breathe.
     
  8. Apr 10, 2013 #7
    well what is the proof that the hydrogen atom has one electron
     
  9. Apr 10, 2013 #8

    sophiecentaur

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    "proof"?
    There are very strong indications that the accepted H model is a good one. (Call it 'right' if you like). If there were a different model, it would have to satisfy all the evidence from the spectrum of light which is absorbed and emitted from an H atom. The model was arrived at in order to explain what the spectrometer tell us and it does it very well.
    You don't need to 'look at' an H atom with a microscope to know what's going on and to predict how it is going to behave under a new set of circumstances. The Proton plus one Electron model works - nuff said.
    Read all about it and you'll see the history of the development of QM.
     
  10. Apr 10, 2013 #9
    Also @magmash have you ever been lied to? I think so .
    Now how do we tell that a person lies? It is obviously not written on ones face but we have methods by which we can predict and say that a person deliberately gives off false information and those methods work quite good most of the time.
    So it is in physics , there are states and whole levels of states like QM which we cannot directly probe or access and see with our eyes but by the way things work out we can spin them back and figure out the part we cannot see.
     
  11. Apr 10, 2013 #10
    well what is the proof that the hydrogen atom has one electron


    All of the subsequent discoveries that have resulted from this knowledge. Unless someone knows of something that goes against 1 electron per hydrogen atom
     
  12. Apr 11, 2013 #11
    could any one here recommend a good book where I can find and read about this thing ?
     
  13. Apr 11, 2013 #12

    sophiecentaur

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    This would depend entirely upon the level of your existing knowledge. Most of the answers you have been given here, so far, have probably assumed that you know more than you do (?). The basics of QM are in early degree courses, although there is some mention in (UK) A Level these days (too superficial to make it worth while, imo).
    I should go for some more Popular Science books (this is NOT a derogatory term, btw), especially if you don't want much Maths in the treatment. A 'chatty' book could help you approach this very broad and ranging subject (there are so many different aspects of modern Physics that tie together and any one specific academic book might be very heavy going). There is some very good stuff available and probably the best thing would be to choose a book which takes your fancy off the bookstore shelf. You would need something about the history of Quantum Mechanics (this stuff is about a hundred years old) which would tell you about the various models that were tried. The basic evidence for the Periodic table of Elements came from 18th and 19th century Chemistry, which demanded a model, based on 'Atomic Number' and 'explained' the discrete chemical nature of the different elements. The needed to know about atomic structure took the studies into Physics. Quantisation of light came out as a result of trying to predict the spectrum emitted by hot bodies. They tried to make a working atomic model which behaves like the planets around a star, but that failed to explain things (Bohr). Then they realised that electrons behave like waves (particularly when bound up in an atom) and the Schroedinger Wave Equation emerged, which gave a solution, for a single electron Hydrogen atom and this solution predicted very accurately, what wavelengths of light would be emitted.
    But I'm not writing a book here.
    Try this link, for a start. and just get trawling. . . . ., which costs nothing but loads of eveningsworth of time.
     
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