Question

Atoms of the same element having the same atomic number but different mass are called _________.

• A. atomic number
• B. mass number
• C. isotopes
• D. isobars

Answer 1

Answer: (C)

isotopes

Atoms of the same element having the same atomic number but different mass are called isotopes. They have same number of protons and electrons but different number of neutrons. For example: Hydrogen - protium ${(}_1^{1}H$), deuterium (${}_1^{2}H$) and tritium (${}_1^{3}H$) are isotopes.