Question

Atoms can be ionized by thermal collisions at very high temperatures. One such ion is Cr²³⁺, a chromium atom with only a single electron.

(a) By what factor are the energies of its hydrogen-like levels greater than those of hydrogen?

(b) What is the wavelength of the first line in this ion's Lyman series?
  nm

Answer 1

The energy of hydrogen-like atoms in the Bohr model can be written as  

Where the terms have their usual meanings.

Fir Cr⁺ , Z= 24, and the reduced mass of Cr can be appreciated with the elctron mass so, So,

For hydrogen atom

So,

Part b

The wavelength is given as