Chapter 11 Chemical Bonds: The Formation of Compounds from ...

11.8 Complex Lewis structures
for some molecules or polyatomic ions, no single
Lewis structure consistent with all characteristics
and bonding information can be written
ex. nitrate ion NO
-
3
step 1 total valence electrons
= 5 + 3 × 6 + 1 = 24
step 2 O O· ·
O N O O : N : O
step 3 24 - 6 = 18
step 4 · ·
: O electron deficient
·· ·· ··
: O : N : O :
·· ·· ··
step 5 · · - · · - · · -
: O : O : : O :
·· || ·· ·· ·· ·· ·· ·· ··
: O : N : O : : O =N : O : : O : N= O :
·· ·· ·· ··
there are three possible Lewis structures
a molecule or ion that has multiple correct
Lewis structures shows resonance
each of these Lewis structures is called a
resonance structure
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