Question

A pair of element have some atomic number but different mass number is called.​

Answer 1

Answer:

same atomic number but different mass number is called isotopes

eg - there are 3 isotopes of hydrogen

protium, tritium, deuterium

Explanation:

hope it helpsssssss

Answer 2

Answer:

Those elements that have the same atomic number but a different mass number are referred to as isotopes. Isotopes occur due to the presence of a different number of neutrons in elements having the same atomic number as mass number is the sum of the number of neutrons and protons.