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Thread: Electron orbital questions

  1. #1 Electron orbital questions 
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    What determines electron orbital shapes? Why so complex?

    We know that what defines an element is its number of protons. Period. Not the number of neutrons, and not even the number of electons. Is it the protons that determine orbital shape? Or is the orbital shape different for different istopes?

    If the protons only affect orbital shape, how do they do so? And why not the neutrons?

    Thanks


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  3. #2  
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    This is not so simple. You need to know quantum mechanics to understand about the shape of orbitals. However neutrons don't affect the shape of orbitals. So isotopes have the same orbital shapes.


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  4. #3  
    Forum Professor Wild Cobra's Avatar
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    Even at that, what we understand to be orbital shapes are still a bit of a mystery. We simply cannot see well to that small scale. I don't think anyone has postulated a sound hypothesis of what causes the various orbital shapes. If they have, i would love to see it. I personally like the beauty of the MO theory, but we really don't know how sound that is, or why the shapes are as they are.
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    Moderator Moderator AlexP's Avatar
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    I don't know how accessible this topic is to you, but it has something to do with spherical harmonics. There's an article on Wikipedia. If you come across any good information, report back to us here. I'd be interested to know more myself.
    "There is a kind of lazy pleasure in useless and out-of-the-way erudition." -Jorge Luis Borges
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  6. #5  
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    You folks are awesome.

    Wild Cobra, you referred to MO. Could you please tell me what MO is?

    AlexP, is the article in Wikipedia about "spherical harmonics?"

    Imteaz Ahmed, thank's for telling me that neutrons don't significantly affect electron orbitals.

    So, is it true, then that the Standard Model--which just about claims to be the answer to everything--doesn't cover electron orbitals?

    I'll continue learning about this. Thanks for your help.
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  7. #6  
    Forum Professor Wild Cobra's Avatar
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    I don't have time to even start writing the little I understand of it. Check out these references:

    Introduction to Molecular Orbital Theory

    Homonuclear Diatomic Molecules

    wiki: Molecular orbital theory

    wiki: Spherical harmonics
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  8. #7  
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    jerich1000, the link that Wild Cobra provided is the one I was looking at.
    "There is a kind of lazy pleasure in useless and out-of-the-way erudition." -Jorge Luis Borges
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  9. #8  
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    isn't it the spdf??
    if an element is in group one and two, its highest energy level will be the S orbital which is like a spherical shape, if its in group 3-0 it will be in the P orbital which is a dumb-bell shape, the transition metals are the D orbital and the ones at the bottom are f.
    is that what u were asking for :?
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    Thanks for sharing buddy.
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  11. #10  
    Forum Bachelors Degree 15uliane's Avatar
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    I thought the number of protons did matter- it determines how many electrons there are, right. And I heard once that there were different shapes for each of the amounts of electrons there cam be.
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  12. #11  
    Moderator Moderator AlexP's Avatar
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    Quote Originally Posted by 15uliane
    I thought the number of protons did matter- it determines how many electrons there are, right. And I heard once that there were different shapes for each of the amounts of electrons there cam be.
    Yes, the number of electrons in an atom will be the same as the number of protons in that atom, but no one ever said the protons don't matter.

    To break it down, since it sounds like perhaps you haven't learned this...there are 'principal energy levels,' or 'shells,' then 'sublevels' or 'subshells,' and then orbitals. The first shell contains only one sublevel, "s," which consists of a single orbital containing up to 2 electrons, as all orbitals do. Then in the second shell there are two subshells, called "s" and "p". s subshells always contain just one orbital, while p subshells contain three (we can call them p<sub>x</sub>, p<sub>y</sub>, and p<sub>z</sub>). Then we continue in a similar fashion, but after this it gets a little more complicated because the d subshell (five orbitals) in the third shell doesn't actually start to fill with electrons until the 4s subshell is filled. Then there is also an f subshell with seven orbitals, which also doesn't fill when you'd expect it to, but don't worry about that.

    As we increase in the number of electrons found in an atom, the electrons fill the orbitals within a subshell according to Hund's Rule, which can be stated simply as "one in each before two in any." That is, as the number of electrons increases, they will occupy an empty orbital if possible, pairing up only when they have to.

    While writing out the 'electron configuration' of an atom, we write first the shell, then the subshell, then superscript the number of electrons in that subshell. So, for example...

    Hydrogen: 1s<sup>1</sup>
    Helium: 1s<sup>2</sup>
    Lithium: 1s<sup>2</sup> 2s<sup>1</sup>
    Beryllium: 1s<sup>2</sup> 2s<sup>2</sup>
    Boron: 1s<sup>2</sup> 2s<sup>2</sup> 2p<sup>1</sup>
    Carbon: 1s<sup>2</sup> 2s<sup>2</sup> 2p<sup>2</sup> (one in p<sub>x</sub>, one in p<sub>y</sub>!)
    Nitrogen: 1s<sup>2</sup> 2s<sup>2</sup> 2p<sup>3</sup> (one in p<sub>x</sub>, one in p<sub>y</sub>, one in p<sub>z</sub>)
    Oxygen: 1s<sup>2</sup> 2s<sup>2</sup> 2p<sup>4</sup> (two in p<sub>x</sub>, one in p<sub>y</sub>, one in p<sub>z</sub>)
    etc.

    I just got the impression that you haven't taken chem, but if you have and already know all or some of this, then at least I had fun recalling all of it, and perhaps someone will learn from it and it will spark some interest in them.
    "There is a kind of lazy pleasure in useless and out-of-the-way erudition." -Jorge Luis Borges
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  13. #12  
    Forum Bachelors Degree 15uliane's Avatar
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    Thanks! I didn't know most of that- Hunds law, describing shell configuration etc. Some video's showed pretty pictures of electron clouds, and had a little info, but nothing specific.
    Also, youre right- i haven't taken chem yet.
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  14. #13  
    Moderator Moderator AlexP's Avatar
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    Well I'm glad you got something out of it. Make sure you do take chem, it's fun.
    "There is a kind of lazy pleasure in useless and out-of-the-way erudition." -Jorge Luis Borges
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  15. #14  
    Forum Bachelors Degree 15uliane's Avatar
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    I will. :-D
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