Question

Atomic numbers of two elements are 20 and 18 respectively, but the mass number of both these elements is 40. What is the name given to such a pair of elements? Define these.

Answer 1

Identification:

1. The two elements that have atomic numbers 20 and 18 and the same mass number 40 are named “Isobars”.

Isobars:

1. Atoms with the same mass number but a different atomic number are called isobars.
2. For example, ${}_{18}{}^{}\mathrm{Ar}^{40}$ and ${}_{20}{}^{}C{a}^{40}$.
3. These are the two elements that are mentioned in the question is Argon and Calcium.