13.11 Obtain approximately the ratio of the nuclear radii of the gold isotope \({ }_{79}^{197} \mathrm{Au}\) and the silver isotope \({ }_{47}^{107} \mathrm{Ag}\).

Hint: Nuclear radius is given by, \(R=R_oA^{1/3}\).
Step 1: Find the mass numbers of \({ }_{79}^{197} \mathrm{Au}\) and \({ }_{47}^{107} \mathrm{Ag}\).
Nuclear radius of the gold isotope Au79197=RAu
Nuclear radius of the silver isotope Ag47107=RAg
Mass number of gold, \(\mathrm{A}_{\mathrm{Au}}=197\)
Mass number of silver, \(\mathrm{A}_{\mathrm{Ag}}=107\)
Step 2: Find the ratio of nuclear radii of \({ }_{79}^{197} \mathrm{Au}\) and \({ }_{47}^{107} \mathrm{Ag}\).

The ratio of the radii of the nuclei is related with their mass numbers as:
RAuRAg=AAuAAg13
=19710713=1.2256
Hence, the ratio of the nuclear radii of the gold and silver isotopes is about 1.23