Question

Which statement best explains why hydrogen’s atomic number is equal to its mass?(1 point)

Answer 1

The atomic number of an element is defined as the number of protons in its nucleus, whereas atomic mass is the weighted average mass of an element's isotopes, usually expressed in atomic mass units (amu).

For hydrogen, the most abundant isotope (protium) has one proton and no neutrons, giving it an atomic number of 1 and an atomic mass of approximately 1 amu. While the atomic mass is not strictly equal to the atomic number due to the presence of other isotopes (deuterium and tritium) and the contributions of neutrons, hydrogen's mass is close to its atomic number due to the light nature of hydrogen and the predominance of the protium isotope in nature.

Thus, a more accurate statement would be that hydrogen's atomic number is equal to its mass in the case of its most abundant isotope (protium).