2- or -2 as superscript?
As @MaxW has said in comments, the correct form is:

$\ce{SO_4^{2-}}$ and $\ce{Fe^{2+}}$

It is just as in math. 
If you have $a+a$ it results in $2a$, not $a2$, and thus:

$\ce{SO_4^{--}=SO_4^{2-}}$ and $\ce{Fe^{++}=Fe^{2+}}$

It is not a stupid question.
IMHO it is a perfectly legitimate question. 
I apologize for those who are downvoting your question.