An isotope of element X has 12 neutrons and 11 protons. Which of the following shows the correct symbol of the ion formed by X ?

As positive particles (protons) are present in the nucleus of isotope of element, it can represent as  ${\text{X}}^{+}$. The chemical identity of an element is depending on no. of protons present in it.

The isotope of an element with 11 protons and 12 neutrons is ${ }_{11}^{23}{\text{X}}^{+}$.

Note: Mass number ,  $\text{A}=\text{n}+\text{p\hspace{0.17em}}=12+11=23$