Identify the set of paramagnetic ions among the following.

Properties common to the elements manganese,iron,cobalt,nickel,and copper include the ready formation by them all of:
$I$. Coloured ions in aqueous solution
$II$. Oxides of nitrogen are formed on reaction with concentrated $HNO_3$
$III$. Chlorides of formula $MCl_2$ and $MCl_3$

The number of electrons in the outermost shell of the $3d-$ transition elements generally remains:

Why is the first ionisation enthalpy of $Cr$ lower than that of $Zn$?

Which of the following elements has a completely filled $4f$ orbital in its ground state electronic configuration?

Match the species in List-$I$ with their correct electronic configuration in List-$II$.

List-$I$	List-$II$
$(1) \ \text{Cr}$	$(A) \ [\text{Ar}] \ 3d^8 4s^0$
$(2) \ \text{Fe}^{2+}$	$(B) \ [\text{Ar}] \ 3d^{10} 4s^1$
$(3) \ \text{Ni}^{2+}$	$(C) \ [\text{Ar}] \ 3d^6 4s^0$
$(4) \ \text{Cu}$	$(D) \ [\text{Ar}] \ 3d^5 4s^1$
	$(E) \ [\text{Ar}] \ 3d^6 4s^2$