# Question #d6aff

Isotopes are the elements with same atomic number but different mass number.Thus all the elements with same number of protons i.e same atomic number are isotopes.For example, ${\text{_1^1H, ""_1^2H, and }}_{1}^{3} H$ are isotopes.
Isobars are the elements with the same mass number but different atomic number.Thus all elements with same mass number are isobars.For example, $\text{_17^40Cl("An isotope of chlorine"), ""_18^40Ar, and ""_20^40Ca " are isobars}$