Nuclei having the same nuclear charge but different masses are called ____?

Nuclei having the same nuclear charge but different masses are called ____?

نیوکلی کا جوہری چارج ایک ہی ہے لیکن مختلف ماسز کو ____ کہا جاتا ہے؟
Explanation
Isotopes are atoms of the same element (same number of protons/nuclear charge) but different masses (different number of neutrons).
Example: Hydrogen-1, Hydrogen-2 (Deuterium), and Hydrogen-3 (Tritium) are isotopes of hydrogen.