Noble gases

[DentalNucleicAcid]

I've noticed that the atomic radius trend doesn't hold true for noble gases. So how would you compare them to other elements in a question? For example, a trick question could ask something like "which is bigger, Rubidium or Xenon?" The instinctive answer would be Rubidium, but I'm guessing it's actually Xenon because it's a noble gas. I know that noble gases are big, but how big are they relative to everything else?

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[Neil Smoove]

The trend on the periodic table for atomic radii is the opposite of electronegativity (left, down/down, left).

Think about it like this, if I have Rb and its single valence electron, that positive nucleus has almost no effect on that negative lone electron, whereas with a noble gas, the octet of valence electrons is filled and that nucleus is holding those babies as tight as it can because he doesn't want to lose them. Since Rb's 1 valence electron is not being pulled in as much as a Noble Gas's 8 v electrons, the electron will be further away from the nucleus thus increasing atomic radii.

Hope that helps

 

[DAT Destroyer]

Your question is so simple that it is DIFFICULT to answer !!!!! When examining atomic radii, do not look at the Noble gases. Noble gases are difficult to react with other compounds, and exist at a wide range of temperatures. Thus, it is difficult to have a control set of experimental parameters when measuring them against other atoms. In 1970, Whittaker and Muntus made assumptions that allowed us to make a reasonable guess.....along came Shannon in 1976 who changed some of those assumptions.....then along came the Quantum Mechanics. Thus....as you can see...a damn mess !!! Numerous studies of ionic radii or bond lengths in crystal structures have been done. The experiments show that as we go down a family, the size does increase as predicted. However, since there are so many difficulties, assumptions, and experimental conditions, we cannot compare them to the other atoms. I hope this makes sense on a question that can stump many a professor.

I give you a gold star for an awesome question !

Dr. Romano

 

[Neil Smoove]

Your question is so simple that it is DIFFICULT to answer !!!!! When examining atomic radii, do not look at the Noble gases. Noble gases are difficult to react with other compounds, and exist at a wide range of temperatures. Thus, it is difficult to have a control set of experimental parameters when measuring them against other atoms. In 1970, Whittaker and Muntus made assumptions that allowed us to make a reasonable guess.....along came Shannon in 1976 who changed some of those assumptions.....then along came the Quantum Mechanics. Thus....as you can see...a damn mess !!! Numerous studies of ionic radii or bond lengths in crystal structures have been done. The experiments show that as we go down a family, the size does increase as predicted. However, since there are so many difficulties, assumptions, and experimental conditions, we cannot compare them to the other atoms. I hope this makes sense on a question that can stump many a professor.

I give you a gold star for an awesome question !

Dr. Romano

And i was stupid to not read his question in its entirety. My bad lol

 

[DentalNucleicAcid]

Your question is so simple that it is DIFFICULT to answer !!!!! When examining atomic radii, do not look at the Noble gases. Noble gases are difficult to react with other compounds, and exist at a wide range of temperatures. Thus, it is difficult to have a control set of experimental parameters when measuring them against other atoms. In 1970, Whittaker and Muntus made assumptions that allowed us to make a reasonable guess.....along came Shannon in 1976 who changed some of those assumptions.....then along came the Quantum Mechanics. Thus....as you can see...a damn mess !!! Numerous studies of ionic radii or bond lengths in crystal structures have been done. The experiments show that as we go down a family, the size does increase as predicted. However, since there are so many difficulties, assumptions, and experimental conditions, we cannot compare them to the other atoms. I hope this makes sense on a question that can stump many a professor.

I give you a gold star for an awesome question !

Dr. Romano

Thank you for the clarification Dr. Romano, I'll conclude that they won't make an unfair comparison on the test.

And i was stupid to not read his question in its entirety. My bad lol

No, thank you!