""_6^13C136C is isotope notation,
C-13 or carbon=13is hyphen notation
Explanation:
""_6^13C136C is isotope notation, atomic number (protons) left bottom, mass number (Protons + neutrons) upper left, then chemical symbol C-13C−13 or Carbon-13 is hyphen notation, don't really need atomic number, because chemical symbol indicates it is carbon, so it must have 6 protons