Consider the lewis structure for the polyatomic oxyanion shown below, where X is the element from the 3rd period (Na- Ar). By changing the overall charge,n, from 1- to 2- to 3- we get three different polyatomic ions. For each of these ions (a) Identify the central atom X. (b) Determine the formal charge of the central atom X. (c) Draw a Lewis structure that makes the formal charge on the central atom equal to zero.