Question

The difference between the wave number of 1st line of Balmer series and the last line of paschen series for Li²⁺ ion is :

• A. $\frac{R}{36}$
• B. $\frac{5R}{36}$
• C. $4R$
• D. $\frac{R}{4}$

Answer 1

Answer: (D)

The difference between the wave number of 1st line of the Balmer series and the last line of Paschen series for Li2+ ion is calculated by using

$\frac{1}{\mathrm{\lambda }}=R{Z}^2(\frac{1}{n_1^2}-\frac{1}{n_2^2})$

For Balmer series ${\mathrm{n}}_1=2{\mathrm{n}}_2=3$

For Paschen serirs ${\mathrm{n}}_1=3{\mathrm{n}}_2=\infty$

Therefore,