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A question about atoms

  1. Jun 16, 2008 #1
    Hello I was wondering if someone could tell me what is in the empty space of an atom. Or if it's actually empty why doesn't it fill up with something or collapse?
    Thanks for taking the time to answer what I hope isn't too dumb a question:smile:
    Nancy
     
  2. jcsd
  3. Jun 16, 2008 #2

    G01

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    The empty space inside the atom is just that- empty space.

    The reason electrons don't collapse into the nucleus is because the laws of quantum mechanics prevent the electron from doing so. For more detail on this question about the atom collapsing, see the FAQ in the general physics forum:

    https://www.physicsforums.com/showthread.php?t=104715
     
  4. Jun 17, 2008 #3
    Thank you for your reply. After reading it this is what I understand. Over 99% of everything is non existant or empty space. And electrons don't actually move they are instead smeared in a geometric pattern around the neculeus and that is what makes the atom stable.

    Is this right?


    Thanks again
    Nancy
     
  5. Jun 17, 2008 #4

    mgb_phys

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    Rather more than 99% by volume but yes.

    The classic picture of electrons like little planets whizzing around the nucleus is wrong but easy to picture. In quantum mechanics everything is smeared, it's just that as you get bigger the smearing is less - so a house is pretty sharp at the edges but a tiny electron is very smeared!
    The reason the electrons can't fall into the nucleus is because they can only have certain energies and can't have the intermediate energy needed when they have fallen halfway.
    It's not that they are locked in a geometric pattern repelling each other like stones in an arch - although that is a pretty good pitcure.
     
  6. Jun 17, 2008 #5
    How remarkable. And thank you very much
    Nancy
     
  7. Jun 17, 2008 #6
    Sorry but I just have one more question. If all this is true and I assume it is, why can't I put my hand through my kitchen table?
    Thanks again
    Nancy
     
  8. Jun 17, 2008 #7

    mgb_phys

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    That's a very good question!
    Materials are solids because the atoms all attract each other. The positive nucleus strongly attracts it's own electrons but also has a weak pull on the electrons on another atom (weaker because they are further away), this bonds all the atoms together. The strength of these bonds determines wether you have a very hard material like diamond or a weak one like water.

    When you try and push atoms together the like-charges repel pushing them back apart - which is why everything doesn't immediately collapse into a neutron star.

    So when you touch a table, the electrons in the atoms on you fingers are repelling the electrons in the atoms of the table. Thats the force you feel.
     
  9. Jun 17, 2008 #8
    OK well that makes sense, thank you. What makes some materials denser than others? I can put my hand through jello.
    Thanks
    Nancy
     
  10. Jun 17, 2008 #9
    oops sorry I didn't read the whole answer I just looked at my email. I got it.
    Thanks again
    Nancy
     
  11. Jun 17, 2008 #10
    Hey nancy1251
    How would the electron collapse? its a wave!
     
  12. Jun 17, 2008 #11

    mgb_phys

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    I think they were asking why the atom doesn't collapse ie. why electrons didn't fall into the nucleus. This is a very good question, answering it took most of 20c physics.
     
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