In a hydrogen atom, when an electron falls from the fifth to the second energy level, it emits a photon of violet light with a frequency of 6.905 x 10^14 S-1. Calculate the energy of this photon. (Plank's constant, h, is 6.626 X 10^-34) E = hf

sodium (na), for example, has one electron in its valence shell. this is an unstable state because that valence shell needs eight electrons to be full. in order to fill its valence shell, find a way to add seven electrons to its valence shell

a:

by the combination of an unlimited number of elements

the right answer is c i just did the question.