Final answer:
The atomic symbols for the three naturally occurring isotopes of argon, which do not typically include the atomic number, are 36Ar, 38Ar, and 40Ar.
Step-by-step explanation:
The atomic symbol for an isotope includes the element's chemical symbol, with its mass number as a superscript on the left and the atomic number as a subscript (although the atomic number is often omitted as the element's symbol already identifies it).
Argon (Ar) has three naturally occurring isotopes with mass numbers 36, 38, and 40. The atomic number of argon is 18, which is the number of protons in its nucleus. The atomic symbols for these isotopes, not including the atomic number, are 36Ar, 38Ar, and 40Ar.