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B Is a single (naked) proton atomic/elemental Hydrogen

  1. Dec 7, 2016 #1
    Okay ... some "simple" questions (I think):

    If a single baryonic proton magically appears in a pure vacuum container (which is otherwise completely empty), can that proton be considered a positive Hydrogen ion?
    Or must a Hydrogen atom lose an electron first (so we just end up with a single, lone proton)?

    Said a different way, is there any way to tell whether a solitary proton was ever the nucleon of a Hydrogen atom?

  2. jcsd
  3. Dec 7, 2016 #2


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    No, there's nothing different between a proton that's be separated from its electron and a proton that was never bound to one in the first place.
  4. Dec 7, 2016 #3

    Simon Bridge

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    Depends on why it matters and in what context the question is being asked.

    There is no way tot tell the history of any particular proton just by looking at it, no. You can deduce that it was once part of something else by the circumstances under which it was detected.

    All else remaining equal H+ is the same as p+. Similarly:
    ##\beta## particle is the same as ##\bar e## ... for that matter, ##\bar\beta## is the same as ##e##
    ##\alpha## particle is the same as ##_4##He##^{++}##

    Which one you use depends on what you want to say and the context you want to say it in... just like any case where you chose between synonyms.
    ie if you say you have a proton, you are saying that the past history of the proton does not matter for the discussion. If you say you have a hydrogen nucleus, then you are kinda implying some reason to think of it in terms of ionized hydrogen (maybe you are about to mess about with electron-proton interactions and you want to be consistent) as opposed to, say, the decay of a neutron.
  5. Dec 7, 2016 #4
    I think the context (or pretext) was my other thread on what is plasma (in the Sun/stars).
    Wiki and other sources note that the "Sun is a nearly perfect sphere of hot plasma" .... and ... is 73% H, 25% He, etc.
    Plasma (as in the Sun) is a soup: protons in a sea of electrons. That is, ionized H, He, etc.
    In the case of H, why (how) can it be considered an "element" (or an "atom") in this soup? If the protons are independent (electronless, i.e., not in orbit), is it the proton's proximity to electrons (in the sea) that gives them a "Hydrogen" identity**? (I think the word used above was electron-proton interaction.)
    Another way to ask it is:
    Other than temperature, what's the diff. between ionized Hydrogen gas (H+ ionized gas, as in Earth's ionosphere, which is relatively low-temp) and Hydrogen plasma (Sun; the plasma is ionized)? E.g., might "charge density" be part of the answer?

    ** It's possible that a pure, simple identity is not possible in the context of Wiki or general-physics descriptions. One would need to learn and appreciate the deep mathematical constructs to absorb a truer Nature of the phenomenon. That is, with symbolic language like English, one merely skirts the issue.
    Last edited: Dec 7, 2016
  6. Dec 7, 2016 #5

    Simon Bridge

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    For consistency, and for historical reasons, atoms are identified by the composition of their nuclei. If singly ionized helium is still helium, then shouldn't doubly ionized helium also be helium? We also know it as an alpha particle - so we can say that alpha particles are a form of helium.

    There is no physical difference between a hydrogen nuclei and a proton, so the terms mean the same thing.
    The English language being the way it is, however, words also carry baggage.

    There is no difference between the individual nuclei. The plasma state is a bulk state of matter ... just like "liquid" and "solid" are bulk states.
  7. Dec 11, 2016 #6
    Because the Sun is electrically neutral, the ions in the plasma are granted to have the exact amount of electrons quite close around to effectuate this neutrality. This is why the plasma can still be regarded as being a composition of its elements, identified by just its ions.
  8. Dec 11, 2016 #7


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    Other than the energy state, there is no difference. Why should there be?

    The elements were identified on earth, so that is our context. Through spectroscopy, we identified the same elements in the sun and stars. There is nothing special there, and we don't need "deep mathematical constructs to absorb a truer Nature of the phenomenon."

    Positively charge protons and nuclei will attract electrons. The sun does have some neutral hydrogen near the surface, due to recombination, but interactions with photons, ions/nuclei, electrons, and other atoms will cause excitation. In deep space, hydrogen will have an opportunity to become hydrogen atoms or molecules. One earth, hydrogen has the opportunity to combine with oxygen to form water, but also, hydroxides, or oxyhydroxides, or with carbon to form hydrocarbons, or both C and O to form a variety of organic compounds.
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