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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: cliffclof on September 06, 2011, 02:46:36 PM

Title: Why only 3 Max valence electrons?
Post by: cliffclof on September 06, 2011, 02:46:36 PM
Why can atoms only have a max of 3 valence electrons?   Why can't Cobalt take one each of the two paired electrons from 3d orbital and the 4s orbital and give 4 valence electrons up ending up looking like [Ar] 3d5?

Hope this is the right section to ask.  Thanks.
Title: Re: Why only 3 Max valence electrons?
Post by: Borek on September 06, 2011, 05:35:59 PM
Quote from: cliffclof on September 06, 2011, 02:46:36 PM
Why can atoms only have a max of 3 valence electrons?

They can have more, so question doesn't make sense.

Quote
Why can't Cobalt take one each of the two paired electrons from 3d orbital and the 4s orbital and give 4 valence electrons up ending up looking like [Ar] 3d5?

Several compounds of tetravalent cobalt are known, so obviously it is possible.
Title: Re: Why only 3 Max valence electrons?
Post by: cliffclof on September 08, 2011, 12:38:05 AM
Thanks for taking your time to answer my question.   It was not obvious to me.  IT is now.   The book I am reading states, "...the loss or gain of one, two or sometimes even three electrons can occur, but an element doesn't lose more than three electrons." -John T. Moore

I found this statement odd especially with Tin.
Title: Re: Why only 3 Max valence electrons?
Post by: AWK on September 08, 2011, 02:01:01 AM
Look at electronegativities. Sn form SnH4, but in this compound electrons are moved towards Sn.