How to Calculate Average Atom Separation in the Sun's Core?

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Homework Help Overview

The discussion revolves around calculating the average separation of atoms in the center of the Sun, specifically in the context of hydrogen's ionization state and electron density. The original poster has previously used the Saha equation to determine that hydrogen is fully ionized at the Sun's core, and now seeks to re-evaluate this by considering atomic separation using the Bohr radius.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the relationship between electron density and atomic density, particularly for hydrogen. Questions arise about how to derive atomic density from electron density and the implications of ionization on average atomic separation. There is also a consideration of whether the average separation calculated indicates a predominance of non-ionized hydrogen.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the implications of electron density and ionization. Some guidance is provided regarding the relationship between electron and atomic densities, but there is no explicit consensus on the implications for the state of hydrogen in the Sun's core.

Contextual Notes

Participants note the lack of explicit information about atomic density and express uncertainty about the implications of their calculations regarding ionization states in the context of the Sun's core conditions.

lycraa
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Homework Statement


in part 1 i used the Saha equation to calculate that the hydrogen in the center of the sun was fully ionized (given temperature and central electron density). part 2 says:

Re-examine the result by computing the average separation of atoms at the center of the sun knowing the radius of the first Bohr orbital.




I'm a little lost here. this would be no problem if i was given the atom density, but I'm not sure how to deal with the electron density
 
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lycraa said:

Homework Statement


in part 1 i used the Saha equation to calculate that the hydrogen in the center of the sun was fully ionized (given temperature and central electron density). part 2 says:

Re-examine the result by computing the average separation of atoms at the center of the sun knowing the radius of the first Bohr orbital.




I'm a little lost here. this would be no problem if i was given the atom density, but I'm not sure how to deal with the electron density

How many electrons are there per atom, for hydrogen? What does that tell you about the number density of hydrogen atoms, given the number density of electrons?
 
well, for NON ionized hydrogen, you would have only one electron. meaning that the number density would be the same as the electron density. So would i be right in saying then, that if the average separation i found using the electron density equals 2* bohr radius, i would have mostly non ionized hydrogen?
 
lycraa said:
well, for NON ionized hydrogen, you would have only one electron. meaning that the number density would be the same as the electron density.

I'm not sure why you have "NON" in all caps. I mean, if you take hydrogen and ionize it, you're still going have equal numbers of protons and electrons. Extra electrons don't just appear out of nowhere.

lycraa said:
So would i be right in saying then, that if the average separation i found using the electron density equals 2* bohr radius, i would have mostly non ionized hydrogen?

I'm sorry, but I don't know the answer to that. On the one hand, this does seem to be the tree up which this problem is barking, by having you reconsider your previous result, and showing that these supposedly "free" electrons don't have much room to move around. On the other hand, I had always thought that the solar core consisted of charged particles, especially since people always talk of the fusion reaction consisting of free protons combining together to form helium nuclei. Besides, although those electrons may, on average, have a mean free path that is not much larger than the orbital of a bound electron, they are still too energetic to remain bound, which would have me lean more towards the ionized picture. EDIT: Remember that I said that I just don't know for sure.
 

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