Which of the following elements form interstitial compounds?

The highest oxidation state observed in first row transition metals is

$Zn$,$Cd$,and $Hg$ show the properties of

The correct statement about iron includes:
$I$) The highest oxidation state of iron is $+ 6$ in $K_2FeO_4$.
$II$) The iron shows $+ 2$ oxidation state with six electrons in the $3d$ orbitals.
$III$) The common oxidation state of iron is $+ 3$ with five unpaired electrons in the $3d$ orbital.

Which of the following elements has the maximum density?

Which of the following has the highest paramagnetic character?