Ionization Energies Of Noble Gases

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Discussion Overview

The discussion centers around the ionization energies of noble gases, exploring why they are considered to have the highest ionization energies in their respective periods despite having larger atomic radii. Participants examine the relationship between atomic radius, effective nuclear charge (Zeff), and ionization energy, while also addressing the definitions and implications of atomic radii.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • One participant questions the statement that noble gases have the highest ionization energies, arguing that their larger atomic radii should imply lower ionization energies due to the increased distance of the outermost electron from the nucleus.
  • Another participant suggests that the inert nature of noble gases, due to their full outer electron shells, makes it difficult to remove electrons, which could explain their high ionization energies.
  • Several participants mention the concept of effective nuclear charge (Zeff) and its relevance to the discussion of ionization energy.
  • There is a request for clarification on the meaning of "Zeff," indicating a need for understanding this concept in the context of ionization energy.
  • One participant asserts that noble gases have large atomic radii, prompting others to challenge this assertion based on periodic trends.
  • Another participant references a source that states atomic radii decrease across a period, suggesting that noble gases actually have the smallest radii in their respective periods.
  • There is a discussion about the varying definitions of atomic radii and how they affect the classification of noble gases in terms of size.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between atomic radius and ionization energy, with no consensus reached on whether noble gases have large atomic radii or the implications of this for their ionization energies. The discussion remains unresolved regarding the definitions of atomic radii and their relevance to the properties of noble gases.

Contextual Notes

Participants reference various definitions of atomic radii, including van der Waals radius and covalent radii, which may lead to different interpretations of the size of noble gases. The discussion highlights the complexity of the relationships between atomic structure and ionization energy without resolving these complexities.

chikis
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Homework Statement



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?

Homework Equations



No equation is involved.

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 believe 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.
 
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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.
 
tal444 said:
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.

So is that the reason why they should have high ionization energies?
 
And the fact that that they have the highest Zeff within each period.
 
chemisttree said:
And the fact that that they have the highest Zeff within each period.

What is the meaning of this "Zeff"?
 
Did any of you agree with me that noble gases have largd atomic radi?
 
  • #10
Redbelly98 said:
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/tutorials/crystalmaker/atomicradii/resources/VFI_Atomic_Radii.jpg
 
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  • #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.
 
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  • #12
chikis said:
http://www.crystalmaker.com/support/tutorials/crystalmaker/atomicradii/resources/VFI_Atomic_Radii.jpg

Data for Rn shows that the table can't be trusted.
 
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  • #13
Borek said:
Data for Rn shows that the table can't be trusted.

What do you mean by Rn?
 
  • #14
Rn stands for Radon.
 
  • #16
tal444 said:
Rn stands for Radon.

Thank you for reminding me.
 
  • #17
chikis said:
So you now see why am asking that question with much zeal and expecting an answer.

Much zeal?
 
  • #18
chikis said:
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/tutorials/crystalmaker/atomicradii/resources/VFI_Atomic_Radii.jpg
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.
 
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  • #19
chemisttree said:
And the fact that that they have the highest Zeff within each period.

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
Redbelly98 said:
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.

You are correct. Am beginning 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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