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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Dolphinsiu on December 15, 2006, 03:34:49 AM

Title: Resonance structure Problem
Post by: Dolphinsiu on December 15, 2006, 03:34:49 AM

What is the resonance structure of ClO3-?

Do it has central Cl with three single bonds to O?dooesn't it?

But Resonance structure means two or more than two Lewis structures to represent single moelcule.
How can I do?

I am not sure whether ClO3- has double bond Cl = O or not!

Please *delete me* Thank you!

Title: Re: Resonance structure Problem
Post by: Dan on December 15, 2006, 04:25:31 AM

http://images.google.co.uk/images?rls=GGLJ,GGLJ:2006-34,GGLJ:en&q=clo3&ie=UTF-8&oe=UTF-8&sa=N&tab=wi

Now you have a structure, you should be able to work out the resonance stuctures.

Title: Re: Resonance structure Problem
Post by: Dolphinsiu on December 15, 2006, 04:30:26 AM

Dan, thanks a lot! ;D

Title: Re: Resonance structure Problem
Post by: Dolphinsiu on December 16, 2006, 04:46:26 AM

But I still do not understand about ClO3- bonding with respect to it electrons.

No. of electrons in ClO3- available = 32

No. of valence electrons = 7+ 6x3 +1 = 26

No. of bonding electrons = 6 (Why there are still two double bonds in ClO3-?)

No.of non-bonding electrons = 20

Title: Re: Resonance structure Problem
Post by: Dan on December 16, 2006, 07:49:33 AM

Quote from: Dolphinsiu on December 16, 2006, 04:46:26 AM

No. of bonding electrons = 6 (Why there are still two double bonds in ClO3-?)

No.of non-bonding electrons = 20

How did you get those numbers?

Title: Re: Resonance structure Problem
Post by: Dolphinsiu on December 16, 2006, 07:51:27 AM

no of bonding electron = 32 - 26 = 6

no.of non bonding electron = 26 - 6 = 20

Title: Re: Resonance structure Problem
Post by: Dan on December 16, 2006, 08:05:06 AM

I don't really see the logic behind this method, I've never seen it before. Could you give an example of a molecule in which this method works?

Surely available electrons = valence electrons? In which case followeing this method will give you zero bonding electrons...

how are you defining available electrons?

Title: Re: Resonance structure Problem
Post by: Dolphinsiu on December 16, 2006, 08:19:48 AM

http://www.mahopac.k12.ny.us/mhs/teachers/langellam/Molecules%20and%20Bonding/C08-notes1.pdf

You see this logic from this website!

Title: Re: Resonance structure Problem
Post by: Dan on December 16, 2006, 08:31:08 AM

OK, fine, where you said "no. of electrons in ClO₃^- available" you meant "number of electrons needed". That confused me.

This method won't work for this ion because Cl is expanding it's octet.

Check this out http://www.nyu.edu/classes/tuckerman/honors.chem/lectures/lecture_6/node8.html

That might help.

You have the structure, so you can just count the bonds and work out the number of bonding electrons, and similarly the lone pairs are the non bonding electrons.

Title: Re: Resonance structure Problem
Post by: Dolphinsiu on December 16, 2006, 09:39:02 AM

Thanks a lot!