Learning objectives

This  module is concerned with drawing the Lewis structure and predicting the shapes of oxoanions. 

Examples include oxoanions
 

• that have a second row element as the central atom and are restricted to four electron pairs at the central atom
  (CO₃^2– and NO₂^–).
   
• that have a third row element as the central atom and can have more than four electron pairs at the central atom
  (PO₄^3– and SO₃^2–)

On completion of the module you should be able to
 

• draw the the Lewis structure of a oxoanion of type EO_n^m– including deducing the appropriate number of double bonds to introduce at the central atom
   
• use the Lewis structure to predict the shape of the oxoanion