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Why does each element only react with certain elements?

  1. Dec 18, 2013 #1
    I want to know what causes this specificity of reactions in between elements. Why does carbon only react with X elements? What are the factors that come into play to cause this specificity?

    From what I understand every element has the potential to bond with every other element but a lot of them would form unstable compounds and would dissociate quickly and so we say x element doesnt react with x element. For example could Na form a covalent bond with Ca but since they would form an unstable compound it quickly dissociates, so we say Na doesnt react with Ca?

    So, does each element have the potential to bond with any other? and because many would form unstable compounds we say they dont react? If not, again what is it that causes the specificity?

    PS- small question here that I dont think it deserves a thread.
    When a polar bond dissociates does the more electronegative element always keeps the electron of the less electronegative element
    (R-OH --> R-O: ( O with extra electron) H+)?

    Also with non-polar bonds does the opposite happen when it dissociates (C-H -> C + H)?
    Where both elements stay neutral?

    Thank you very much.
  2. jcsd
  3. Dec 18, 2013 #2

    Simon Bridge

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    whether a covalent bond is formed depends on how many electrons are in the outermost shell (how full it is for eg) and what other possibilities there are that may be more likely. Eg. An atom could just strip the electrons from another one.

    not always but generally.
    The element is more electronegative because the electron is more likely to be found close to it.


    The dissociation of molecules can be quite complicated.
    Some end configurations are more likely than others... But look at the stability of the possible ions in your example.
  4. Dec 18, 2013 #3
    Okay thanks man, but for what reasons do we say X element will only react with X elements?

    Or is it that all the elements have the potential to form bonds with every other element but a lot of the compounds that would form would be very unstable and just dissociate?
  5. Dec 18, 2013 #4

    Simon Bridge

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    We "say" that stuff because that is true.
    A noble gas, for instance, does not react with anything.

    Platinum is an example of something that reacts so well with everything that it can tear other molecules apart in the process - but the bonds are so unstable that they break apart almost right away.

    The comparison should help you with your question.

    How stable the bonds are and what atoms will react with which depends on the electron configuration and what else they could do.
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