Three isotopes of carbon have mass numbers 12, 13, and 14.

(a) Write the full atomic symbols for these three isotopes, including mass number and atomic number.

(b) For each isotope, indicate the number of neutrons and protons in the nucleus.

(c) For each isotope, determine the total number of nucleons in the nucleus.

(d) How can all three isotopes be carbon if they have different mass numbers?