The maximum oxidation state of $Cr$ is:

Coloured salts are formed by

Which one of the following belongs to the $3d-$ transition series?

Which of the following statements is correct?

Explain the variations in atomic radii of transition elements along the period. The following table provides data for the first transition series:

Element	Sc	Ti	$V$	Cr	Mn	Fe	Co	Ni	Cu	Zn
Metallic Radius $M$ (pm)	$164$	$147$	$135$	$129$	$137$	$126$	$125$	$125$	$128$	$137$

Which one of the following statements is not correct?