Can I create a custom format that allows for the number following the
letter(s) representing an element to be in superscript form?

ex. H1 (I want the 1 to be superscript for the hydrogen 1 isotope), or C12
(I want the 12 to be superscript for the carbon 12 isotope)

The element can be 1 letter or 2 letters - I don't know if that complicates
things (i.e. hydrogen is represented by H, but Helium is represented by He).
Also the isotope number could be 1, 2, or 3 digits.

Thanks if anyone can help.