Question

Which of the following are isotopes and which are isobars ? Argon,Protium,Calcium,Deutirium

Answer 1

Argon and Calcium are isobars as their atomic masses are 40 (Ar- 18,22; Ca- 20,20)

Protium ($H^{1} _{1}$ ) and Deutrium ( $H^{2} _{1}$ ) are isotopes as they have the same number of protons i.e. 1 but different numbers of neutrons i.e 1 and 2 respectively.