Which of the following is ferromagnetic

The oxoanion in which the oxidation state of the central atom is same as its group number in the periodic table is

Which of the following is diamagnetic transitional metal ion

$Zn$ and $Hg$ belong to the same group, they differ in many of their properties. The property that is shared by both is

The correct order of decreasing third ionisation enthalpy of $Ti,\, V,\, Cr,\, Mn$ is

Addition of non-metals like $B$ and $C$ to the interstitial sites of a transition metal results the metal