Question:
The total number of isotopes of hydrogen and number of radioactive isotopes among them, respectively, are :
Correct Option: , 3
Solution:
Total number of isotopes of hydrogen is 3
$\Rightarrow{ }_{1}^{1} \mathrm{H},{ }_{1}^{2} \mathrm{H}$ or ${ }_{1}^{2} \mathrm{D},{ }_{1}^{3} \mathrm{H}$ or ${ }_{1}^{3} \mathrm{~T}$
and only ${ }_{1}^{3} \mathrm{H}$ or ${ }_{1}^{3} \mathrm{~T}$ is an Radioactive element.