In which of the following systems will the wavelength corresponding to n = 2 to n = 1 be minimum?
We know from Rydberg's equation, the wavelength λ of emission spectrum when electrons move from n₂ energy level to n₁ energy level, is given by,
Now, here n₁=1 and n₂=2 are fixed. So wavelength is inversely proportional to
Among the options, lithium ion has the highest atomic number, Z=3.
Hence, option (d) is the correct answer.