The electronic configuration of $Ag$ atom is

Gadolinium (atomic number $= 64$) is a member of the $4f$ series. Its electronic configuration in the $+3$ oxidation state is $[Xe] 4f^7$. What is the ground state electronic configuration of gadolinium?

Pair of transition metal ions having the same number of unpaired electrons is $:$

In the $3d$ series of transition elements,the atomic radii from $Cr$ to $Cu$ are approximately the same because:

Electronic configuration of $Gd$ $(Z = 64)$ is

Elements which generally exhibit multiple oxidation states and whose ions are usually coloured are