The common oxidation state of scandium $(Sc)$,a transition element,is:

The highest oxidation state observed in first row transition metals is

The correct order of ionic radii for $Y^{3+}$,$La^{3+}$,$Eu^{3+}$,and $Lu^{3+}$ is:

Given below are two statements $:$
Statement $I : CrO_3$ is a stronger oxidizing agent than $MoO_3$
Statement $II : Cr(VI)$ is more stable than $Mo(VI)$
In the light of the above statements,choose the correct answer from the options given below.

In the periodic table,metals usually used as catalysts belong to:

Variable valency is shown by