What happens when an X-ray is shot at an atom

Find the mass, in grams, of 5.00*10^23 molecules of f2

Consider hydrogen in an excited state n = 5n=5 that emits photons to reach the ground state. there are various possible transitions other than straight to the ground state that can occur; for example, it can drop to the n = 3n=3 state followed by the n = 3n=3 to the ground state transition. which of the possible transitions will result in the emission of a photon in the visible region?

How many grams of phosphorus are contained in 5.09 moles of phosphorus?