Consider an atom that has an electron in an excited state. the electron falls to a lower energy level. what effect does that have on the electron?

The only effect is that excess amount of energy absorbed by the electron will released to fall on lower energy state.

Explanation:

When transition occur from lower energy level to higher energy level require a gain of energy. Electron could not jump into higher energy level without gaining thew energy.

When electron jump into lower energy level from high energy level it loses the energy.

The process is called excitation and de-excitation.

Excitation:

When the energy is provided to the atom the electrons by absorbing the energy jump to the higher energy levels. This process is called excitation. The amount of energy absorbed by the electron is exactly equal to the energy difference of orbits.

De-excitation:

When the excited electron fall back to the lower energy levels the energy is released in the form of radiations. this energy is exactly equal to the energy difference between the orbits. The characteristics bright colors are due to the these emitted radiations. These emitted radiations can be seen if they are fall in the visible region of spectrum.