Match species given in Column I with the electronic configuration given in Column II.

Column I		Column II
(i)	$\mathrm{Cr}$	(a)	$\left[\mathrm{Ar}\right]3{\mathrm{d}}^{8}4{\mathrm{s}}^0$
(ii)	${\mathrm{Fe}}^{2+}$	(b)	$\left[\mathrm{Ar}\right]3{\mathrm{d}}^{10}4{\mathrm{s}}^1$
(iii)	${\mathrm{Ni}}^{2+}$	(c)	$\left[\mathrm{Ar}\right]3{\mathrm{d}}^{6}4{\mathrm{s}}^0$
(iv)	$\mathrm{Cu}$	(d)	$\left[\mathrm{Ar}\right]3{\mathrm{d}}^{5}4{\mathrm{s}}^1$
		(e)	$\left[\mathrm{Ar}\right]3{\mathrm{d}}^{6}4{\mathrm{s}}^2$

When an electric discharge is passed through hydrogen gas, the hydrogen molecules dissociate to produce excited hydrogen atoms. These excited atoms emit electromagnetic radiation of discrete frequencies which can be given by the general formula.

$\overline{\mathrm{\nu }}=109677 \left(\frac{1}{{\mathrm{n}}_{\mathrm{i}}^2}-\frac{1}{{\mathrm{n}}_{\mathrm{f}}^2}\right)$

What points of Bohr’s model of an atom can be used to arrive at this formula? Based on these points derive the above formula giving description of each step and each term.