Chemical Forums

Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Atome on January 23, 2007, 07:13:59 PM

Title: Charges on Polyatomic Ions
Post by: Atome on January 23, 2007, 07:13:59 PM
Good day everyone,

          In my science textbook, there is a list of Polyatomic Compounds with their respective Ionic Charges. I was wondering if you could tell me how I can derive the ionic charge from scratch.

For example, NH4 has a charge of +1. Could you please tell me how I find out without knowing beforehand that it is +1? My mistake, I meant to type +1. Thanks for correcting it!

Thanks a lot in advance.

James
Title: Re: Charges on Polyatomic Ions
Post by: enahs on January 23, 2007, 07:35:01 PM
It is called formal charge.
http://en.wikipedia.org/wiki/Formal_charge

That might not be the best reference, as it has lots of other information. Calculating formal charge is fairly easy, so just try searching google for formal charge.

Although, I would ask you double check what your book says and how you wrote your question?

*edit* Bah, he edited his and corrected it from +1 to -1 while I was posting. But for some reason this site does not do the modify tag if you edit it very recent to your posting time? Ignore that comment now.
Title: Re: Charges on Polyatomic Ions
Post by: english on January 24, 2007, 02:10:16 PM
Since when did +NH4 have a -1 charge?

Title: Re: Charges on Polyatomic Ions
Post by: enahs on January 24, 2007, 05:56:02 PM
Quote from: k.V. on January 24, 2007, 02:10:16 PM
Since when did +NH4 have a -1 charge?



Bah, I spaced out. I originally wrote the post correct, questioning his charge. I do not know what made me think he changed it to the correct answer, which was wrong. I think I am developing some form of dyslexia or something, as I have been doing things like that a lot lately, with stuff I read in a book or on a chalk/white board, not just a computer screen....