Question

S) The elements with some atomic number but different
mass is called____​

Answer 1

The elements with the same atomic number but different mass are called isotopes.

Step-by-step explanation:

Isotopes are atoms of the same element that differ in the number of neutrons in their nuclei. That is, isotopes are atoms that have the same atomic number - equal numbers of protons - but different atomic mass - different number of neutrons. Their chemical properties, however, do not differ.