The energy levels of hydrogenlike one-electron ions of atomic number Z differ from those of hydrogen by a factor of Z^2. Predict the wavelength of the 2s--->1s transition in He+.

Explanation:

For a hydrogen-like atom, the spectral line wavelength can be computed by using the formula:

where:

emitted radiation of the wavenumber   = ???

atomic no of helium Z = 2

Rydberg's constant

the initial energy of  the principal quantum = 2

the initial energy of  the principal quantum = 2

Now, the emitted radiation of the wavenumber can be computed as:

Now, the wavelength for the transition can be computed by using the relation between the wavelength λ and the emitted radiation of the wavenumber  , which is:

i'm pretty sure it is letter c.) car