(i) All the isotopes of any element have the same atomic number that is the number of the protons is the same but have different mass number due to a different number of neutrons.

(ii) As the physical properties of any element like boiling temperature, melting temperature, density, etc. are determined by the mass number of the element.

(iii) The physical properties of isotopes differ from each other because they have a different mass number but their chemical properties are the same because they are determined by an atomic number.