Question

(a) What are radioactive isotopes? Give two examples of radioactive isotopes.
(b) Give any two uses of radioactive isotopes.
(c) An element Z contains two naturally occurring isotopes Z3517 and Z3717. If the average atomic mass of this element be 35.5 u, calculate the percentage of two isotopes.

Answer 1

Radioactive isotopes are the elements of the isotopes which are having same atomic number but different atomic mass

Answer 2

Explanation:

• (a) Radioactive isotope is otherwise called, radionuclide, radioisotope or radioactive nuclide.
• This atom has an excessive nuclear energy because of which the atom becomes very unstable.
• The radioactive atoms’ half-lives range spans over the range with the magnitude of over 55 orders and has no limits.
• (b) Some of the applications of radioactive isotopes are radioactive dating and preservation of food.
• It also has various other applications such as medical applications, tracers, dating once-living objects, and food preservation.
• (c) One isotope will be 75%, whereas the other isotope will have 25%. Let us consider that the first isotope’s fractional abundance is ‘x’ and that of another isotope is $'(1 - x)$'. So, the total fractional abundance becomes equal to 1.

         For isotope 1:

           Isotope’s mass = 35 u, Fractional abundance = x

        For isotope 2:

           Isotope’s mass = 37 u, Fractional abundance = 1 - x

           Element z has the  

           Average atomic mass of element Z = 35.5 u

• When the values are substituted in the equation, we obtain fractional abundance of 0.75 and 0.25 for isotopes 1 and 2, respectively.