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What the heck is ionized hydrogen?

  1. Sep 28, 2010 #1
    My professor just attempted to explain ionized hydrogen to us. She said that an ionized hydrogen atom is basically a proton. But I don't understand why that would still be considered hydrogen if it no longer has an electron.
  2. jcsd
  3. Sep 28, 2010 #2


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    Because elements are determined by number of protons, not by number of electrons.
  4. Sep 28, 2010 #3
    So a proton cannot exist in it's own state?
  5. Sep 28, 2010 #4
    Ionized hydrogen is protons. That's all. Strictly speaking, maybe it shouldn't be called "ionized hydrogen" but if the context is mostly chemical, it may ease the vocabulary, especially at the elementary level.

    Protons can practically only exist on its own in a vacuum. In air, there's always something around to neutralize it.
  6. Sep 28, 2010 #5


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    Sure it can. It just depends on what environment the proton/hydrogen atom finds itself in.
  7. Sep 28, 2010 #6


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    If it helps, don't think of it as "Hydrogen", but as "A Hydrogen Nucleus" instead.
  8. Sep 28, 2010 #7
    I don't think that neutralize is a proper term or concept here.
    I understand your point, but those less knowledgeable might not get the nuance inferences.
  9. Sep 29, 2010 #8
    Interesting. Would a hydrogen nucleus not also contain a neutron, whereas a lone proton is just that – a lone proton (however such a thing may not be practically)? So that critically, as the term ‘ionised hydrogen’ would imply to me, it does refer specifically to a former complete hydrogen atom – one proton, one neutron, one electron – that has lost its electron, rather than a lone proton of unspecified provenance.
  10. Sep 29, 2010 #9
    @ Ken Natton, here is the issue concerning hydrogen isotopes (1st paragraph).


    The table further down shows that 99.9885 % of hydrogen atoms have only one proton as a nucleus.

    @ pallidin, in chemistry, I think it is quite standard to use "neutralize" this way i.e. neutralizing an acid is nothing but "neutralizing" lone protons.
  11. Sep 29, 2010 #10
    Isn't hydrogen normally H2? The H2 molecule could lose one electron and still be ionized H2.
  12. Sep 29, 2010 #11
    They were talking about atomic hydrogen.

  13. Sep 29, 2010 #12
    Believe me guys, I defer to you absolutely, I don't doubt that you know better than me. But as I understood the story, the existence of neutrons was first deduced from the fact that atomic weight quadruples as atomic number doubles. It was thus deduced that there had to be another particle in the nucleus, same in quantity as the proton, of equivalent mass, and of neutral electrical charge. I do understand that isotopes of the same element have different numbers of neutrons in the nucleus, but it is a bit of a surprise to learn that hydrogen atoms usually have no neutrons. That doesn't fit with the story. Or was the fact that hydrogen didn't fit that pattern always a bit of a mystery?
  14. Sep 29, 2010 #13


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    Actually the most common isotope of Hydrogen is 1H, which has just the proton and an electron. This renders the second part of your statement:

    ...more or less moot. You are not incorrect, but I don't think anyone can make the claim that "ionised hydrogen" "usually" refers to the case in which there is one proton, one neutron, and no electron.
  15. Sep 29, 2010 #14
    Not sure about the story, as there isn't really that pattern seen. Unless you mean the atomic weight is 4x the previous atomic number. Hydrogen does fit that pattern.

    H: Atomic number 1, atomic weight 1.
    He: Atomic number 2, atomic weight 4.
    Be: AN 4, AW 9
    O: AN 8, AW 16
  16. Sep 29, 2010 #15
    Yeah, sorry, I mis-stated it a little. Hunting round I find that the neutron was discovered by Chadwick, but only after Rutherford had inferred its existence by virtue of the fact that atomic weights did not increase as expected if the nucleus contained only protons. That was the basic story I wasn’t quite remembering.
  17. Sep 30, 2010 #16
    Not all atoms will contain Neutrons. Hydrogen especially, being the lightest element, has "no need" for Neutrons in its nucleus (although it is possible, just unlikely, as Dr Lots o Watts pointed out.) As you move down the periodic table to heavier elements, isotopes (variants of the element with added Neutrons) become more common.
  18. Sep 30, 2010 #17


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    Calling a proton "ionized hydrogen" is like calling a square a "rectangular rhombus". It is perfectly correct and is just a different way of saying the same thing.
  19. Sep 30, 2010 #18


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    If it isolated from conductors or other atoms. In some plasmas that are sufficiently hot, protons and electrons exist freely, and there may be few neutrals, simply because they get smacked by nuclei, electrons, gamma rays or brehmstrahlung.

    On earth, we produce protons by stripping away electrons and putting protons in an accelerator in a vacuum, or some kind of magnetic bottle. But protons repel and eventually they can leak out of a magnetic bottle. In general, nature favors neutral atoms.

    Free neutrons decay with a half-life of 10.23 minutes. Otherwise, they prefer to be in nuclei.

    A deuteron is the nucleus of a deuterium atom (2H, or D). Deuterium is not too common on earth. A triton is the nucleus of a tritium atom (3H, or T). It is artifically produced on earth, although deuterons and tritons can be produced by spallation reactions involving solar protons or cosmic rays with terrestrial nuclei. The triton decays to 3He.

    Hydrogen is the only element with an isotope that contains no neutrons, 1H or protium. All the other elements have at least one neutron in the nucleus, and there is a stability criterion such that stable nuclei 'generally' have the same number of neutrons as protons or slight surplus of neutrons, but there are exceptions. 8Be is an interesting exception - it's not stable. 12B is another interesting unstable nucleus. Except for 10B and 14N, the light elements with odd numbers of protons tend to be unstable if N=Z, so for stability N>Z.
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