Nature of matter: state question

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Discussion Overview

The discussion centers on the nature of phase changes between elements with similar atomic masses, specifically exploring why elements like nitrogen and carbon exhibit different phases despite being neighbors on the periodic table. The conversation touches on quantum mechanical explanations, atomic structure, and bonding as potential factors influencing these phase differences.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants question the lack of explanation for phase differences between elements with similar atomic masses, suggesting it may reflect a gap in current understanding.
  • One participant proposes that quantum mechanical factors could explain phase changes, although they express a desire for accessible literature on the topic.
  • Another participant discusses the role of atomic energy levels and orbitals in determining the reactivity and phase of elements, contrasting inert gases with reactive metals.
  • It is noted that under certain conditions, such as low temperature or high pressure, nitrogen can exist as a solid, similar to carbon.
  • Participants explore the idea that bonding types (e.g., sigma and pi bonding) and orbital configurations influence whether an element is found in a gaseous or solid state.
  • One participant highlights that noble gases do not bond easily and are typically found in the gas phase, while elements that can form multiple bonds tend to be solids.
  • There is acknowledgment of the complexity of the topic, with no simple answers provided regarding the reasons behind phase differences.

Areas of Agreement / Disagreement

Participants express varying degrees of understanding and curiosity about the topic, with some agreeing on the importance of bonding and atomic structure while others remain uncertain about the lack of definitive explanations for phase changes. The discussion does not reach a consensus on the underlying reasons for these phenomena.

Contextual Notes

Participants note the complexity of the topic, indicating that multiple factors such as atomic structure, bonding, and energy levels contribute to phase differences, but the discussion does not resolve these complexities or provide a definitive framework for understanding them.

Ferrum
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im curious as this question came up in a chemistry forum and it's more of a physics question I believe .

State changes between elements of near similar number , what constitutes the extreme phase changes ?

It was answered that there is no real answer for why the phase differences occurs at all. Well it was bluntly stated that it didn't have an answer . I'm curious how true this is ? Or if it is a phenomenon of lack of current understanding ?

Thank you anyone for taking time to answer this
 
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I sorry, but I don't understand the question. What do you mean by "elements of near similar number?". And what do you call an "extreme" phase change?

Maybe you could give an example of what you are contemplating.
 
Yes , I was vague . The gas element nitrogen is diatomic beside a solid state carbon on the periodic table, they are neighbors , but their phases are different , why ? Their atomic mass is similar but this phase change , at least in lighter elements seems to shift between solid and gas without any reason ? The chemistry forums stated , against my dismay, that there was not and didn't need an answer for this it "just was ", I find this disturbing .

I assumed a quantum mechanical explanation for the phase changes was most likely the reason , but I'm an undergrad and still learning . I have not found sound peer to peer literature that breaks down why this is that I can understand at my level. It's not a homework question it's a general interest .
 
Ferrum said:
Yes , I was vague . The gas element nitrogen is diatomic beside a solid state carbon on the periodic table, they are neighbors , but their phases are different , why ? Their atomic mass is similar but this phase change , at least in lighter elements seems to shift between solid and gas without any reason ? The chemistry forums stated , against my dismay, that there was not and didn't need an answer for this it "just was ", I find this disturbing .

I assumed a quantum mechanical explanation for the phase changes was most likely the reason , but I'm an undergrad and still learning . I have not found sound peer to peer literature that breaks down why this is that I can understand at my level. It's not a homework question it's a general interest .

But that's not the ONLY difference between. You look at Xe being an inert gas, and you add one more atomic number, and you get Cs, one of the most reactive substance around (pure Cs in liquid form will combust spontaneously in air!).

The problem here is that it isn't JUST the addition of one more atomic number. You need to look at the atomic energy levels and orbitals. There is a reason why He, Ne, Ar, Xr, etc. are inert, while H, Li, Na, K, etc.. can be highly reactive. Atoms with just 1 electron in the valence shell behaves differently than atoms with 2 electrons in the valence shell, or full number of electrons in the valence shell. This also plays a part in whether they form molecular bonds, or will tend to form a solid lattice.

BTW, the phase issue isn't that crucial, because I also also get solid N at a low enough temperature or high enough pressure. So under such conditions, both C and N are solids.

Zz.
 
I see it a little clearer now , thank you, I also was wondering about this at standard pressure and temp. I can visualize a lot of the change being product of orbital configuration and lattice structure as well , but I was wondering why this wasn't brought to light at the other forum . It seemed to be an energy level matter.

I understand the bonding a little . So while carbon and nitrogen are not complete as are not hydrogen and lithium . Helium , complete shell and it's a gas and add 1 to each partlical and you have a solid lithium, why? Energy? It's it pi or sigma bonding based ? At standard pressure and temps , why?

It seemed like a orbital energy level answer to me too , I'm wondering why the responder just dodged the answer i guess , there seems to be an answer for the phase differences . Queer to me
 
There is no simple answer to your question, but it does boil down to bonding. Atoms that don't bond to others (noble gases) or only bond in pairs (like H, N, and O), will be found in the gas phase. Elements where one atom can easily bond to more than one other atom of the same kind, like C, Li, Na, etc., will form a solid.
 
DrClaude said:
or only bond in pairs (like H, N, and O), will be found in the gas phase.
Unless they are heavy, like iodine.
 
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Ok thank you, these were assumptions I'd had , I appreciate the replies very much
 

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