The statement that is $INCORRECT$ about the interstitial compounds is

Which of the following ions is colourless in spite of the presence of unpaired electrons?

The highest oxidation state of $Cr$ is:

The electronic configuration of $Ag$ atom is

Which one of the elements with the following outer orbital configurations may exhibit the largest number of oxidation states?

Why are the $E^o$ values for $Mn^{2+}/Mn$,$Zn^{2+}/Zn$,and $Ni^{2+}/Ni$ more negative than expected? The table below provides the values:
| $E^o_{Mn^{2+}/Mn}$ | $E^o_{Zn^{2+}/Zn}$ | $E^o_{Ni^{2+}/Ni}$ |
| :--- | :--- | :--- |
| $-1.18 \ V$ | $-0.76 \ V$ | $-0.25 \ V$ |