1. Which of the following electron transitions between two energy states (n) in the hydrogen atom corresponds to the emission of a photon with the longest wavelength?

(a) 2 → 5.

(b) 5 → 2.

(c) 5 → 8.

(d) 8 → 5.

2. If we set the potential energy of an electron and a proton to be zero when they are an infinite distance apart, then the lowest energy a bound electron in a hydrogen atom can have is

(a) 0.

(b) -13.6eV.

(c) Any possible value.

(d) Any value between - 13.6eV and 0.