Which of the following elements has the maximum first ionisation potential?

In transition elements,the orbitals that are partially filled by electrons are:

The number of valence electrons present in the metal among $Cr$,$Co$,$Fe$,and $Ni$ which has the lowest enthalpy of atomisation is

Match the metal ions given in Column-$I$ with the spin magnetic moments of the ions given in Column-$II$ and assign the correct code.

Column-$I$	Column-$II$
$(a) \ Co^{3+}$	$(i) \ \sqrt{8} \ B.M.$
$(b) \ Cr^{3+}$	$(ii) \ \sqrt{35} \ B.M.$
$(c) \ Fe^{3+}$	$(iii) \ \sqrt{3} \ B.M.$
$(d) \ Ni^{2+}$	$(iv) \ \sqrt{24} \ B.M.$
	$(v) \ \sqrt{15} \ B.M.$

$(a) \quad (b) \quad (c) \quad (d)$

Which of the following metal ions will have the maximum number of unpaired electrons?

Amongst the following,the lowest degree of paramagnetism per mole of the compound at $298 \ K$ will be shown by: