Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: galpinj on August 08, 2016, 10:40:11 PM
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Hey guys,
I realize this is a pretty dumb question, but I was wondering if anyone knows which trend is more "powerful", left to right across a period or up/down a group. For example, if one was asked to rank the atomic radii of potassium and Iodine based off periodic trends, which would be larger? Potassium is on the left (left is larger), but Iodine is at period 5, which is further down (radius increases as you move down). Since both elements have something going for them, how am I to know which one is in fact larger?
The answer is potassium, btw, but I still appreciate an explanation as to why one trend is more "powerful" (horizontal or vertical)
Edit: While I'm here, I'm also curious if anyone knows if subshells are always more stable if they are filled. I am aware that a half-filled or fully-filled D subshell is more stable than other configurations, but does this hold true for the S subshell? Would alkaline earth metals (s2) be more stable (have a higher ionization energy) than alakli metals (s1)?
Thank you
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You're going to have to immediately define "powerful" in chemistry terms, and then use those terms only in your question. Otherwise, people will start to try to help, and you'll change your definition of "powerful", just to make them work more. And we'll end up with a multiple page thread, that says nothing.
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Thank you for the response,
By "powerful" I simply mean exerts a greater influence. To be more precise, atomic radius increases from right to left and from top to bottom, so which element would be larger, one located in the top left or one located at the bottom right? Both elements would satisfy only part of the trend to be considered "large", so of the two which is larger, and why? I have found questions like this, and have been unsure which aspect of this trend has a greater influence on atomic radius.
Moreover, the question can also be expanded to included such trends as electronegativity, ionization energy, metallic character, etc. For example, EN increases from left to right and from bottom to top, so would At (bottom right) be stronger than Li (top left).
To sum up, I am simply curious which aspect of the periodic trends is having a greater influence (horizontal or vertical) for any of the trends.
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There you have a chart with the solid's "molar volume" of the elements
https://www.webelements.com/iodine/physics.html
I don't see a linear trend horizontally, nor a reason to claim that the vertical trend would be stronger or weaker.
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Thank you for the response,
No problem.
By "powerful" I simply mean exerts a greater influence.
That statement is meaningless, applied to elements, in the periodic table.
To be more precise, atomic radius increases from right to left and from top to bottom,
That's better.
so which element would be larger, one located in the top left or one located at the bottom right? Both elements would satisfy only part of the trend to be considered "large", so of the two which is larger, and why? I have found questions like this, and have been unsure which aspect of this trend has a greater influence on atomic radius.
I don't know which. I do know that some tables include this information, so you'll know which one "wins" and you can infer what effect is "winning."
Moreover, the question can also be expanded to included such trends as electronegativity, ionization energy, metallic character, etc. For example, EN increases from left to right and from bottom to top, so would At (bottom right) be stronger than Li (top left).
If you skip astatine, given that there are never more than a few pg on the planet Earth at any given time, an look above to iodine, do you still have to ask, which is more metallic or more electronegative, lithium or iodine?
To sum up, I am simply curious which aspect of the periodic trends is having a greater influence (horizontal or vertical) for any of the trends.