Suppose a hydrogen atom is in the n = 4 excited state. what is the largest number of photons that can be emitted as the atom returns to the ground state?

One photon is emitted each time an electron downs one or more levels of energy.

The ground state of hydrogen is n = 1.

So the electron has the possibility to release one photon when the electrons goes downward from n = 4 to n = 3, one more photon when goes downward from n = 3 to n = 2 and one more photon when goes downward from n = 2 to n = 1. So, the largest number of photons that can be emiited as the atom returns fo the ground state (n = 1) is 3.

3