[dumbo]

Hello,
I am not sure if this question was answered before.

if electronegativity is the ability to accept an electron, then highest electronegative value is for those elements that have the greatest propensity to attract an electron.

I do not understand the pic below. Why is Ne has higher electronegative value when all its shells are filled.

 https://ecampusontario.pressbooks.pub/app/uploads/sites/869/2021/04/image2-6.jpg

[dumbo]

https://www.researchgate.net/publication/338923717/figure/fig1/AS:961465569775635@1606242663460/Plot-of-electronegativity-ch-in-au-as-a-function-of-atomic-number-Elements-in-red-and.png

[Babcock_Hall]

An early definition of electronegativity was proposed by Mullikan was that it was the average of the ionization energy and the electron affinity.  Ionization energy is the energy change to take an electron away from a gaseous, neutral element, and electron affinity is the energy change upon giving an electron to a gaseous, neutral element.  Electronegativity differences can explain the energies of forming covalent bonds in some instances, but there are other chemical properties that don't correlate with it.  I do not know the answer to your question, however.

[dumbo]

thanks babcock_hall,

looking forward for someone to throw light on my predicament.

https://www.researchgate.net/publication/338923717/figure/fig1/AS:961465569775635@1606242663460/Plot-of-electronegativity-ch-in-au-as-a-function-of-atomic-number-Elements-in-red-and.png

[Babcock_Hall]

IMO your definition of electronegativity was incomplete.  A working definition might be a measure of how equally or unequally electrons are shared in a bond.

[dumbo]

My definition is not complete: agree. But question still stands. Why does the graph show that Ne has high electronegitivity, similary  Ar and other nobel elements. 

[Babcock_Hall]

I gave you a clue in a previous answer.  What is the trend in ionization energies?

[Borek]

I don't have good answer to the question either, but electronegativity in general is not a "hard" property, one that can be directly measured in terms of absolute values. It is rather a handwawy proxy suggesting what kind of behavior to expect. No wonder it sometimes fails, especially for exotic cases.

Not something worth hair splitting IMHO.

[dumbo]

Thanks for your reply.. did not make me happy but i will keep at it.

[Babcock_Hall]

https://chemed.chem.purdue.edu/genchem/topicreview/bp/ch7/ie_ea.html#pattern
If you look at the ionization energies of the second row elements, they peak at neon.

[Babcock_Hall]

I skimmed over the Wikipedia entry on electronegativity, and there are even more definitions and scales than I realized.  My educated guess is that the electronegativity of Neon is undefined on the Pauling scale, but on the Allen and Mullikan-Jaffe scales, it is at the top.  Overall, I agree with Borek; I would add that some chemical properties correlate well with electronegativity while others do not.  Students can get over-enamored with electronegativities, because they are taught early on about it.