The most stable oxidation state of $Mn$ is

In which of the following transition metal ions is $d-d$ transition possible?

Which of the following elements exhibits ferromagnetic properties?

Although $Cr^{3+}$ and $Co^{2+}$ ions have the same number of unpaired electrons,the magnetic moment of $Cr^{3+}$ is $3.87 \ BM$ and that of $Co^{2+}$ is $4.87 \ BM$. Why?

In the $3d$ series of the $d$-block elements,which element has the maximum atomic size?

The coinage metals are