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Dumb question but here goes-cations/anions?

  1. Feb 12, 2015 #1
    I don't know if I'm overthinking this or not enough, but how to ions have charges? I don't mean that mechanically but literally. How is it that an cation is positive and anion negative? I understand that the cation has lost an election and the anion has gained, but how does that specifically affect the atom's (ion's) charge?

    Perhaps my question is: do atoms have charges? They are attracted to one another by necessity, does that mean elements are "positive" and "negative?" That doesn't make any sense, does it?

    EDIT: i.e. O has a charge of 2-, because it wants six elections, and if it achieves this it becomes an anion, but how is it that O is at first considered "negative"? Is not an electron always an electron? Or is it just saying it can never "give away" it's two electrons? So bonds have nothing to do with an actual "charge" but the limitations of the atom's composition? Did I answer my own question? Can anyone clarify?
     
    Last edited: Feb 12, 2015
  2. jcsd
  3. Feb 12, 2015 #2

    Borek

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    Atoms are neutral. They become charged after they gain or lose electrons.
     
  4. Feb 12, 2015 #3
    Then how are they neutral if they're seeking to be stable?
     
  5. Feb 12, 2015 #4

    Borek

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    Please elaborate, I don't see where the problem is. You seem to be implying something neutral can't be stable - there are plenty of stable, neutral things (including some atoms).
     
  6. Feb 12, 2015 #5
    Yes, that was my impression. If it's unstable (missing a "perfect" valance) it's still "neutral"? Perhaps I'm using the word incorrectly?
     
  7. Feb 12, 2015 #6

    Borek

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    Yes, electrically it is neutral.
     
  8. Feb 12, 2015 #7
    Okay. But then why are these neutral atoms seeking to have 8 electrons if they exist as they are? Can they just not help it due to their attractions?
     
  9. Feb 12, 2015 #8

    Borek

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    It is not about attraction, it is that in a different arrangement of nuclei and the electrons the system will have lower energy, so given a chance it will rearrange itself to get there.
     
  10. Feb 12, 2015 #9
    Ah, okay. I think I kinda get it now--It just happens. Thank you for your all help with my questions, I feel a bit more stable in my understanding.
     
  11. Feb 12, 2015 #10

    cgk

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    Tribo, you may also be confused over the notion of "stable": Most neutral atoms (and many neutral other things) will be stable in the sense that if you put them in a vacuum with *nothing* around them to interact with, they will not fall apart on their own. This includes even extremely reactive entities like Fluorine atoms. A different notion of "stable" is: Will the neutral atoms remain neutral atoms if they can interact with something else? And, as Borek said, there are often re-arrangements of the nuclei and electrons which will have lower total energy than two neutral atoms have. Thus, there may be molecules, ions, molecular ions, condensed phases, etc. formed which lie lower in energy.
     
  12. Feb 12, 2015 #11
    I think I got it. Unstable atoms can't keep themselves together on their own while the neutral atoms hold up even as their valence varies.

    Mind if I drag this on some more--what do you mean by "lower total energy?" The atomic mass weight? I think I see everything else that you're saying, although I don't yet know how it's all done.
     
  13. Feb 13, 2015 #12

    Borek

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    The explanation I prefer at this stage is that when these reacting atoms rearrange, they emit energy is some form (for example mixture gets warm, or emits light). That means their total energy after the reaction is lower than it was before (regardless of how we define the "total energy").
     
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