If a Li 2+ ion, initially in the 2nd excited state absorbs a photon of light with a fequency of 2.82 X 10^6 GHz, what will be the final energy level for this electron? Show all stepts to get final energy level.

i have no clue what this question is even asking :[?

Use the formula

h*frequency = E to get the energy of the photon
h is Planck's constant.

The energy of the n=2 state is
E2 = -R/2^2 = -R/4
R is the Rydberg constant for Li, expfressed in Joules. It equals 9 time the Rydberg cosntant of hydrogen, because of the Z=3 charge of the nucleus.

Use the formula
E = En - E2 to get the energy of the upper state

Then use
En = -R/n^2 to get the upper level quantum number, n.

If you find the Rydberg constant expressed in wave numbers (cm^-1) instead of Joules, follow the same procedure but use the wave number of the transition (1/wavelength) instead of the energy of the photon, E.

h c * wavenumber = energy