The number of unpaired electrons in $Zn^{2+}$ is

Consider the following pairs of elements and identify the pairs of elements which have nearly same atomic radius.
$I$. $Y, La$
$II$. $Zr, Hf$
$III$. $Mo, W$
$IV$. $Cr, Mo$

Determine the name and symbol of the element with atomic number $103$.

The most stable oxidation state of $Cr$ in aqueous medium 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 has the maximum number of unpaired electrons?