[ayat94]

c. The lines in the emission spectrum of hydrogen are assigned to various series.
The Brackett series involves n→ 4 transitions where n =5, 6, 7,… to ∞
 Use RH = 2.18 x 10-18 J in your calculations
Determine the full wavenumber range of possible transitions in this series using
calculations for two suitably chosen emissions. Report the emission line
positions in cm-1
.

[idest]

Let the emmision energy is ΔE, then ΔE=E₄-E_n=-R_H(1/16-1/n²). (Notice this is negative value.)
And the emmision energy is also the photon energy E=hν=hc/λ.
Wave number is defined as k=2π/λ. and we can express it in terms of the emmision energy using aforementioned relations. And then get the min. and max. of wave number.

[ayat94]

can u show me the calculation please

[ayat94]

Sketch the Molecular Orbital energy level diagram for N2. The order of energy
levels is different to that in F2. Explain why this is the case. (This requires some
book work).

[billnotgatez]

Both ayat94 and idest
should read forum rules if you have not already done so

[idest]

I had read the forum rule. But I am sorry if I did go too far.

[ayat94]

is anybody going  to help me

[Borek]

is anybody going  to help me

You have to show your efforts, so far all you do is you ask for a spoonfeeding. Sorry, that's not how the forums works.