Chapter 12, Problem 53A

Interpretation Introduction

Interpretation:

The term resonance is to be described giving examples.

Concept introduction:

The concept resonance comes into play when properties of a molecule can’t be explained by a single structure.

Answer to Problem 53A

Resonance is a phenomenon of having more than one structure of a molecule. The various structures are resonating structures and the most stable structure is resonance hybrid. The molecules or ions which show resonance are: benzene, carbonate ion, sulphate ion, nitrate ion.

Explanation of Solution

Resonating structures of sulphate ion:

  

Sulphur has six valence electrons. One electron is shared by each oxide ion and two electrons are shared by oxygen atom and no electron pairs are left unshared.

Resonating structures of phosphate ion:

  

Phosphorus has five valence electrons. One electron is shared by each oxide ion and two electrons are shared by oxygen atom and no electron pairs are left unshared.

Resonating structures of $S{O}_3{}^{-}$are:

  

Sulphur has six valence electrons. One electron is shared by each oxide ion and two electrons are shared by oxygen atom and one electron pair is left unshared.

Conclusion

Thus, resonating structures are drawn when one structure cannot explain all the properties of the molecule.