Posted by Raj on .
Draw the Lewis structures for BrO3- and ClO4- and indicate their correct number of additional resonance structures.
I'm a little confused about this. For example, I've got the correct original form of BrO3- down. Where all 3 O atoms are single bonded to Br, and the Br itself contains a lone pair. While each O contains 3 lone pairs. Altogether I've drawn 9 ADDITIONAL resonance structures.
They include having 2 oxygen atoms double bonded to the Br, with those two oxygens having 2 lone pairs. The third oxygen has a single bond to the Br and 3 lone pairs. And the Br itself has a lone pair. I've also drawn the two equivalent structures for this ion. The other ones I've drawn are the Br atom single bonded to two of the O's, which contain 3 lone pairs (the Br also has a lone pair) and double bonded to one of the O's with 2 lone pairs. Plus this one's 2 equivalent resonance structures. Lastly, I've drawn one of the O's triple bonded to the Br and the other two single bonded. Plus the two equivalanet structures for this.
Altogether that makes 9 additional structures for the BrO3-. But would equivalent structures count as additional structures? And also are the structures I mentioned even possible at all, would they count as resonance structures?
Your Lewis structure for BrO3^- should be trigonal planar with a double bond between the central Br atom and one of the O's. Since the double bond could be with anyone of the O's, you can draw three different resonant structures.
ClO4^- is tetrahedral with only one stable Lewis structure.
It's an oxoanion. Br has 7 valence electrons. O has 6 valence electrons. The - means the molecule has one more electron. Can't have a double bond on any of the Os or it breaks the octet rule for both the Br and O.
Single bonds on all the O and a lone pair.