Definition of Isobar
Isobars are defined as
The atoms that have same number of nucleons. Isobars of different chemical elements have different atomic number but have the same mass number.
Alfred Walter Stewart in 1918 suggested the term isobars. It is derived from the Greek word in which isos means equal and baros means weight.
Example of Isobar
Argon, potassium, and calcium having atoms of the same mass number 40.
18Ar40, 19K40, 20Ca40 where 18, 19 and 20 shown as subscripts are the atomic numbers of the three elements respectively are isobars. Since the atomic numbers are different their chemical properties are also different. The structure of argon, potassium, and calcium are given below.