How can isotopes of hydrogen be represented?

Hydrogen has three primary isotopes, which are differentiated by their mass numbers. These isotopes include protium, deuterium, and tritium. Protium, the most common isotope, has one proton and zero neutrons, represented by the symbol ¹H. Deuterium has one proton and one neutron, represented as ²H, while tritium has one proton and two neutrons, denoted as ³H.

This concise representation highlights both the element (hydrogen, H) and the specific isotopes based on their mass number. The representation of isotopes using mass numbers is a standard notation in chemistry, allowing for easy identification and differentiation between isotopes of the same element.

The other options provide incomplete or unclear representations. Although options C and D include correct mass numbers, they lack the full element symbol, which is vital for clarity. The option that lists H, He, Li contains elements rather than specific isotopes of hydrogen, making it irrelevant to the question. Therefore, the correct representation of hydrogen's isotopes is through their complete symbols including both their mass numbers and the element symbol.