Answer:
In Cl[tex]_2[/tex], the 2 is a subscript because it indicates there are 2 of the same elements. The Lewis structure would display it as Cl-Cl.
On the other hand, a superscript would indicate a specific charge.
All subscripts show the amount of the specific element there is.
An example would be O[tex]_2\\[/tex] or N[tex]_2[/tex], they both show that there are 2 of the same elements.
If the subscript is outside a parenthesis such as [tex]Ca_3(PO_4)_2[/tex] it indicates there are 2 [tex]PO_4[/tex] molecules.
