Due to covalent bonding, the transitional metals are

$Fe,$ $Co$ and $Ni$ have valuable catalytic properties in process involving

$\operatorname{Zr}\,(\mathrm{Z}=40)$ and $\mathrm{Hf}\,(\mathrm{Z}=72)$ have similar atomic and ionic radii because of :

Assertion : Cuprous ion $(Cu^+)$ has unpaired electrons while cupric ion $(Cu^{2+})$ does not.

Reason : Cuprous ion $(Cu^+)$ is colourless whereas cupric ion $(Cu^{2+})$ is blue in the aqueous solution.

For which of the following transition metal ion is shown highest magnetic moment having outer electronic configuration

The stability of $Cu ^{2+}$ is more than $Cu ^{+}$salts in aqueous solution due to -