Question

define isotope and isobars? difference between isotope and isobar?

Answer 1

Isotopes are defined as the atoms of same element having same atomic number but different mass number.For example- Isotopes of hydrogen.And Isobars are two element having same mass number but different atomic numbers.For example- Argon and Calcium

Answer 2

those atom which have same mass no.s but different atomic no.s
e.g.  the atomic no. of calcium and argon is 20 and 18 but the mass n0. is same 40
 
those atoms which are same elements (or same atomic no. ) but have different mass no.s
e.g.  chlorine(Cl) are the same elements or say have same atomic no.s(17) but they have different mass no.s (35 and 37).

Or you can say that also isotopes and isobars are vice-versa.