ddaedwards ddaedwards Today at 10:10 AM Chemistry Answered A radioactive nuclide has 53 protons and 78 neutrons. Which is the symbol of this nuclide? Superscript 53 subscript 78 upper I. Superscript 78 subscript 53 upper P t. Superscript 131 subscript 78 upper P t. Superscript 131 subscript 53 upper I.