Question

What is the wavelength of the transition from n = 2 to n = 1 for Li2+? Li2+ is a hydrogen-like ion. Such an ion has a nucleus of charge +Ze and a single electron outside this nucleus. The energy levels of the ion are -Z2RH/n2, where Z is the atomic number.
nm
In what region of the spectrum does this emission occur?
X-ray region
infrared region
ultraviolet region
visible light region
gamma ray region

Answer 1

For the H atom,
1/wavelength = R(1/1 - 1/2^2) where R = 1.097E7 and the transition is from N = 2 to N = 1.
For H like atoms, R is replaced by RZ^2 where R is 1.097E7 and Z is the nuclear charge of 3. Therefore,
1/wavelength = RZ^2(1/1 - 1/2)
Solve for wavelength.