Isotopes are atoms of the same element that have the same number of protons but a different number of neutrons. Therefore, isotopes have the same atomic number (number of protons) but a different mass number (number of protons plus number of neutrons). Typically, the mass number is written as a superscript in front of the elemental symbol. Which of the following pairs are isotopes of each otherDetrium and tritiumhydrogen and proton