Consider the following statements ( X and Y stand for two different...

Consider the following statements ( $X$ and $Y$ stand for two different elements) (I) ${ }_{22} \mathrm{X}^{\mathrm{m}}$ and ${ }_{33} \mathrm{Y}^{\mathrm{m}}$ are isotopes. (II) $_{42} X^{86}$ and $_{42} Y^{\text{as }}$ are isotopes. (III) $_{\%} \mathrm{X}^{174}$ and $_{88}^{\mathrm{Y}^{17}}$ have the same number of neutrons. (IV) $_{2} \mathrm{X}^{235}$ and ${ }_{24}^{235}$ are isobars. The correct statements are: