Question

What are isobars?

Answer 1

Isobars:

The atoms of different elements having different atomic number but same mass number (or atomic mass) are known as isobars.

Example:

1. Consider two elements:

Calcium $\mathbf{\left(}\mathbf{Ca}\mathbf{\right)}$ having atomic number $20$ and mass number $40$ i.e. ${}_{20}{}^{40}\mathrm{Ca}$.

Argon $\mathbf{\left(}\mathbf{Ar}\mathbf{\right)}$ having atomic number $18$ and mass number $40$ i.e. ${}_{18}{}^{40}\mathrm{Ar}$.

1. These elements have same mass number but different atomic numbers.
2. Thus, ${}_{20}{}^{40}\mathrm{Ca}$ and ${}_{18}{}^{40}\mathrm{Ar}$ are isobars.