The following figure shows three electronic transitions in a hydrogen atom (X, Y, Z). Beside the figure are three electromagnetic waves (1), (2), and (3) - drawn on the same scale. Identify the electronic wave that corresponds to the transition in Y.

Is light absorbed or emitted when an electron in the hydrogen atom goes from n = 8 and n=3?

Calculate the amount of energy needed to ionize hydrogen:

a. in its ground state

b. in its 2nd excited state with n = 4.

Lithium is considered a hydrogen-like atom because it has one valence electron. Calculate the energy required to completely remove the valence electron from a lithium atom in its ground state. Find the wavelength of light that has enough energy in a single photon to achieve this. 

Determine whether each transition in the hydrogen atom corresponds to absorption or emission of energy.

a. n = 3 → n = 1

b. n = 2 → n = 4

c. n = 4 → n = 3