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Fall 2014 Midterm #7

Posted: Mon Oct 31, 2016 9:55 pm
by Ronica_Patel_3G
The problem asks to draw the lowest energy Lewis structure of HClO3. I drew the Lewis structure as a tetrahedral shape and got zero formal charges for all of them, but when I checked with the answers, it was a trigonal pyramidal structure. Can someone explain what I did wrong and the easiest way to make the Lewis structure?

Re: Fall 2014 Midterm #7

Posted: Tue Nov 01, 2016 3:55 am
by Alicia_Miller_3F
Hi,
Your drawing gives one of the oxygen 10 electrons which is more than the octet it needs. You have all the formal charges correct at zero with your model except for those extra two electrons that must be held by chlorine rather than the oxygen, hence why hydrogen is shifted to the oxygen with a single bond to carbon to still complete the octet but leave those extra 2 on the chlorine. The oxygen you currently have has a formal charge of -2 rather than 0 like desired.
Hope this helps!

Re: Fall 2014 Midterm #7

Posted: Tue Nov 01, 2016 12:56 pm
by Sarah_Heesacker_3B
Also, the problem specifies that HClO3 is an oxoacid, which means that the hydrogen is bonded to the oxygen and not the central atom, which in this case is chlorine.