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Hydrogen on one side, Helium on the other, and nothing in between ?

  1. Oct 5, 2005 #1
    It may seem like my question should be in another board on periodic tables but I need answers from here. I'm hoping for vigorous criticism on a couple of deliberately annoying questions;

    1) Why do the inner shells have a specific electron capacity - and the outer ones all the same ?

    2) Is there any chance that helium and hydrogen fit as well into other columns in the periodic table ? (I'm not saying they do - just hoping for an explanation in terms of physics rather than chemistry)

    3) Could there be atomic orbital shells, or sections of those shells, that we cannot detect ?

    4) Whilst chemists like to flatten out the orbital shells, is there any room for physicists to envision multi dimensional electron shells ?

    5) Could it be that on the chemists flattened out electron shell model (okay I admit they don't really use them :) ), that dark matter is in fact atoms with electrons in inner shells before we even see the Hydrogen shell ?

    I think its best I stop there - but I would really appreciate any comments or criticism. Any details about why my comments are stupid would be welcomed immensely.

    Many thanks

    Last edited: Oct 5, 2005
  2. jcsd
  3. Oct 5, 2005 #2


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    Is there a reason why you decided to start ANOTHER thread on a similar issue while refusing to address the questions and points brought up on the one you started earlier?

  4. Oct 5, 2005 #3
    Which thread was that ZZ ?
  5. Oct 5, 2005 #4


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  6. Oct 5, 2005 #5
    My applogies but thats the first time I've done that. I have several different areas of interest and there is the possibility of me loosing a single thread somewhere somehow unintentionally.

    I will return to the new questions I have here if the previous thread doesn't answer them.

  7. Oct 6, 2005 #6
    Questions 1 to 4 are answered easily by any reading on the atomic shell theory.

    Note that this theory has very solid foundations and is extremely well verified in experimental physics and chemistry.
    The whole structure of the periodic table reflects the shell theory as well as the known chemical similiraties between the elements.
    And this is one of the many evidences.
    Spectroscopy since more than a century has also generated a dense network of experimental evidences for the atomic theory as it is known today.

    Today it is still a subject of refinement and application, like for modeling drugs, protein folding, materials ab-initio properties,
    ... but the foundations are not a subject anymore.

    It is hard to say, but if you want to contribute to the field, you need first to learn the fundamentals and then still further.
    Then you will understand that question 5 makes no sense for atomic theory.
  8. Oct 6, 2005 #7
    Okay thanks anyway. No one has given me a fundamental reason why n cannot be negative but maybe I'll see it as self evident after some more reading.
  9. Oct 6, 2005 #8


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    That's just grossly incorrect. The "capacity" of the n'th shell is 2n^2. That number increases parabolically with n, it does not saturate or "stay the same".

    An oft considered alternative position for H is above F, but changing the position of an element in the periodic table does nothing to change our understanding of it.

    There can be little green goblins that we can not detect. But what significance does making such a statement have ?

    Chemists do not flatten out orbital shells.

    See above.

    Before you question accepted science, learn it.
  10. Oct 6, 2005 #9
    And why don't you ask about complex n ?
    And why are space coordinates real, by the way ?

    This kind of questions have in general several levels of answer.

    One level is that scientists have tried to build theories close to reality and their effort have had this result.
    So, we may assume the theory is somehow close to the reality.
    Therefore, trying to bring changes to the theory should be motivated.
    How would you motivate negative n ? Did you find a failure of QM in the domain of atomic physics that motivates your question?

    Another level is that of understanding the existing theory. And here, if you read the basic QM calculations for atomic/hydrogen levels, you find out that raw mathematics brings you to positive values of n. Observe that for the energy levels it doesn't matter any way, since they depend on n². Observe also that the solution of the SE for the radial eigenfunctions leads to laguerre polynomials that are numbered starting from 0 up to any positive integer. After all, n is positive simply because the levels are counted from 0 to infinity, and it happens that in this way the energy levels are given by the famous 1/n² formula.

    The alternative you suggest would amount to counting the level from -infinity to +infinity. How would you do that? (there are ways to do it of course but the energy levels would not change, neither the wavefunctions)

    Finally note that n is the numbers or zeroes in the radial wavefunction. Since electrons have a wave-like behaviour, it would be not surprise that their probability of presence exhibits regions of high density and -eventually regions of zero probabilty. It happens that the states of hydrogen can be specified by the number of zeroes of the radial wavefunction, with of course the other quantum numbers. Clearly there is no reason to look for negative n.
    Last edited: Oct 6, 2005
  11. Oct 7, 2005 #10
    Okay many thanks guys. I know my questions where bizarre but I find it easier sometimes to know why things are as they are but seeing why they are not something else. With your answers and the kind help of a couple of people somewhere else I'm happy to stop barking up this particular tree in terms of a fundamentally mirrored and dimensionally shifted version of atomic structure.

    But I do have another question - if you have H+ ions 'floating' around in empty space, what would they appear like to us ? Would they be detectable by telescope ? Would they become Hydrogen within a short time ?

    Many thanks

    Last edited: Oct 7, 2005
  12. Oct 8, 2005 #11


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    An H+ ion is a proton. It's virtually impossible to "see" one of these with the best microscopes around. How do you imagine one could see free protons floating in space ?

    As for the question of there being no elements between H and He, keep in mind that the order of classification of elements can be generated entirely INDEPENDENTLY of any knowledge of electrons and electronic configurations. The order is simply determined by the number of protons in the nucleus. H has 1, He has 2, and that's that.
  13. Aug 1, 2009 #12
    As Gokul said, the reason that there is no elements between them is that you can't use half of a proton. :)

    The reason that they don't appear right next to each other on the periodic table is that H shares properties with the others in the first column, and He shares properties with others in the last column. Unfortunately, H is a kind of weird atom, because even though it only has 1 valence electron, it could easily become a positive ion (losing an electron, like the 1st column) or a negative ion (gaining an electron, like the second to last column) H shares a lot of traits with many different columns on the periodic table, so scientists basically decided to put it in the first column, just for classification purposes. I've heard it refered to as the "floating atom" because of this.

    (If any of this is wrong, pleease let me know!) :)
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