Question

Name or state the following:

Elements having same mass number but different atomic number.

Answer 1

Isobars: Elements which have the same mass number but different atomic number are called as isobars.

• Example: ${}_{20}{}^{40}\mathrm{Ca}$ and ${}_{18}{}^{40}\mathrm{Ar}$ have different atomic numbers. Atomic number of Calcium (Ca) is 20 and atomic number of Argon (Ar) is 18 but mass number of both of these elements are 40 (indicated in the superscript of the symbol).