Which among the following cations produces a colourless aqueous solution in its respective oxidation state?

Which of the following pairs of ions are both colored in aqueous solution? (Atomic numbers: $Sc = 21, Ti = 22, Co = 27, Ni = 28, Cu = 29$)

In the $3d$ transition series,as the atomic number increases,the paramagnetic character:

Which of the following graphs is the correct representation of the relationship between atomic number $(Z)$ and the magnetic moment of $d-$block elements? [Outer electronic configuration : $(n - 1)d^x\ ns^{1\ or\ 2}$]

The elements with the highest and the lowest enthalpy of atomisation respectively,for first row transition elements are:

The electronic configuration of ${ }_{59} Pr$ $(Praseodymium)$ is