Question:
Will ${ }^{35} \mathrm{Cl}$ and ${ }^{37} \mathrm{Cl}$ have different valencies? Justify your answer.
Solution:
The atomic number $(Z)$ of the element $(C l)$ is $17 .$ Its electronic distribution is $2,8,7 .$ It has valency $(8-7)=1$ which is the same for both the species, which act as isotopes.