Name five atoms and the five colors that describe them?

Order each of the following sets of five atoms and ions according to decreasing size. "1" largest and "5" smallest. 

O 
S^2- 
O^2- 
Te^2- 
Se^2- 

I know the more negative the ion, the larger the element. but i dont understand how to do it when they all have the same charge, and an element with no charge. 

It was necessary to redeem the world and he knew that his son was the only way