Question

For the electronic transition from $n=2$ to $n=1$ which one of the following will produce the shortest wavelength?

• A. $H$ atom
• B. $D$ atom
• C. ${He}^{+}$ion
• D. ${Li}^{+2}$ion

Answer 1

Answer: (D)

${Li}^{+2}$ion

According to Rydberg equation:

$\frac{1}{\lambda }=R_H{z}^2(1/n_1^2-1/n_2^2)$

As from the equation, the atomic number and wavelength are inversely related. More the atomic number, the shortest will be the wavelength.

The atomic number of lithium is 3 and is the highest of all. So, this nucleus will have the shortest wavelength.

Hence, option D is correct.