Consider the following.

(I) The order of first ionisation enthalpy of first three elements of 3rd period is $\mathrm{Mg}>\mathrm{Al}>\mathrm{Na}$.

(II) The element with electronegativity of 3.5 is chlorine.

(III) The order of sizes of ions $\mathrm{Mg}^{2+}, \mathrm{Na}^{+}, \mathrm{F}^{-}$and $\mathrm{O}^{2-}$ is $\mathrm{Mg}^{2+}<\mathrm{Na}^{+}<\mathrm{F}^{-}<\mathrm{O}^{2-}$.

(IV) The IUPAC name of the element with atomic number 106 is bohrium.

The correct statements are