Hello, Dawson,
I didn't put a lot of thought into this, but here's what fell out:
The higher shells have the higher engeries, and vice versa. That would mean that the greater the distance between shells, the greater their energy difference. Ehen an electron "falls" from a higher shell to a lower one, it gives off the energy difference in the two loacations. Lucky for us, much of that energy is dispersed as electromagnetic waves, or photons. We can enjoy fireworks, for one instance.
Photons with shorter wavelengths have higher energy than those with longer wavelengths. My reasoning is thus that the greater the difference in shells, the greater the energy and shorter the wavlength. So choice d would have the shortest wavelength and choice b would be the longest.
Bob
(a) n = 1 to n = 6
(b) n = 4 to n = 6 LONGEST
(c) n = 4 to n = 9
(d) n = 2 to n = 11 SHORTEST
