Ionization Energies Of Noble Gases

  1. 1. The problem statement, all variables and given/known data

    I was going through my past question and answer, I then came across this:
    "The noble gases have the highest ionization energies in each period".
    I then wondered why and how the above statement is a reality. How can the above statement be true when the noble gases have large atomic radi?

    2. Relevant equations

    No equation is involved.

    3. The attempt at a solution

    I know that Ionization energy, is the energy required to remove the outermost electron from a gasous atom.
    If you say that the noble gases has the highest Ionization energies, how true is that when you know that the noble gases have a relatively large atomic radius?
    I belive that the noble gases should have the lowest ionization energy since they have large atomic radius. This (lowest ionization energy) is possible because the larger the atomic radius the farer the distance of the outermost electron from the attraction of the nucleuos, thereby making it easier for outermost electron to escape. In such circustance, the outermost electron will leave with a very small energy.
    From my statement above, I have it that the noble gases have the lowest and not the highest ionization energy.
    If you the person viewing this my thread has a contrary view to mine on this concept on discusion feel free to share your own opinion. Let's see how we can collectively solve this problem.
     
  2. jcsd
  3. You are forgetting that the noble gases are (generally) inert. They all have a full outer shell of electrons, which makes it very difficult to remove any electrons.
     
  4. So is that the reason why they should have high ionization energies?
     
  5. chemisttree

    chemisttree 3,721
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    And the fact that that they have the highest Zeff within each period.
     
  6. What is the meaning of this "Zeff"?
     
  7. Did any of you agree with me that noble gases have largd atomic radi?
     
  8. Borek

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  9. Redbelly98

    Redbelly98 12,038
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  10. I have open the link which you pasted in. The link contained information concerning trends in periodic table, like ionization enegy, atomic radi, electron affinity, electronegative and the rest.
    The issue is that my question has not been answered. My question is this, did any of you agree with me that noble gases have large atomic radius in each period?
    Watch the link below and see for your self why am asking that question. In that link, you will see that in each period you go, the noble gases have large atomic radi which is equal in size to those of akali metals. So you now see why am asking that question with much zeal and expecting an answer.

    http://www.crystalmaker.com/support...er/atomicradii/resources/VFI_Atomic_Radii.jpg
     
  11. From http://en.wikipedia.org/wiki/Periodi...#Atomic_radius: "The atomic radius tends to decrease as one progresses across a period from left to right". This quote clearly states that atomic radii DECREASES from left to right. As noble gases are on the very right, this would mean that noble gases actually have the SMALLEST radii in their respective periods.
     
  12. Borek

    Staff: Mentor

  13. What do you mean by Rn?
     
  14. Rn stands for Radon.
     
  15. Redbelly98

    Redbelly98 12,038
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  16. Thank you for reminding me.
     
  17. chemisttree

    chemisttree 3,721
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    Much zeal?
     
  18. Redbelly98

    Redbelly98 12,038
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    Okay, that is a puzzling image. But I have found an explanation in the page where that image is posted:

    http://www.crystalmaker.com/support/tutorials/crystalmaker/atomicradii/index.html

    There is a lot of information there, about different ways that "atomic radii" can be defined. Scroll down to the "Table of Atomic Radii" on that page, which lists radii for several different definitions of that term. Under most definitions, noble gases have the smallest radius in their respective row of the periodic table. Only for the "van der Waals radius" is the noble gas radius larger as shown in your figure. I'm a little puzzled as to why they chose that one to use in their chart at the very top of their page, but they did.

    Most importantly, look at the definitions of radii that use either (1) an isolated atom, or (2) an atom covalently bonded to another atom -- for these definitions, the noble gases are the smallest in their respective rows.
     
  19. from the link you pasted in, I saw that after calculating Zeff for Na cation or F anion and neutral Ne, the aticle stated it clearly that Na cation has the highest Zeff and thus the smallest atomic radius.
    But we are not talking about cation or anions here.
     
  20. You are correct. Am begining to come to my senses. Initialy whenever the word radi is mentioned, what comes to my mind is nothing but atomic radi. I never knew there are diffrences. I used to think that ionic, vandawal, atomic and convalent radi are all the same. But in this thread am discussing atomic radi. All the same, I say thank you for the awareness.
    I now accept that atomic radi decreases left to right across a period thus the nobles gases being at the extrem right of each row should have the smallest atomic radi.
     
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