Electrons & The color of things?

Question

When an electron goes down to a lower energy level, it emits light. So, how then, if I am right, does something, say a desk stay brown? Do the electrons' energy levels repeatingly decrease? HELP!

STOP, PLEASE, saying remarks about my questions, in my chemistry book, it says "ELECTONS EMIT LIGHT!!!!!!" - CHEESE!!!!!!!!!!!!

Answer 1

John C is kind of right, although he should be aware somethings can emit light (like when burning barium salts). The electrons moving energy levels is the kind of thing that happens when you BURN salts... directly giving high amount of energy to electrons so that they may move to a higher energy level (or shell), and so emit light when they move down.

In the case of a desk, it is not getting enough energy for the electrons to move energy levels. The energy that is absorbed by the desk from the light is also being radiated as heat. There is therefore constant gain and loss of energy, meaning that the electrons never amass enough energy to completely shift levels.

Answer 2

This decay process does not happen until all the electrons are in the ground state. This is because electrons are fermions, i.e. they have half integer spin and are subject to the Pauli Exclusion Principle. This principle is a result of the statistics of the particles and says that two identical fermions tend to be much further away from each other than two distinguishable particles would be. So, after my rant, the Pauli exclusion principle only allows two particles in the same state and each have opposite spin. So the electrons in an atom stack up in energy levels, and ones in higher energy levels cannot fall into the spaces of the lower level electrons unless these electrons jump up in energy. Also, during electron emission, angular momentum must be conserved, so for example, an s-state electron cannot jump to an s-state.

Answer 3

You erroneously assume that visible objects emit light. This is untrue, they REFLECT light (unless, of course, they actually do give off light).

Say you have a brown desk in a pitch black room. Can you tell that the desk is brown without any light reflecting off of it?

edit: in retrospect, my implication that energy emission and reflection are completely different mechanics is wrong. Yes, OP, you are correct in saying that "the electrons' energy levels repeatingly decrease". When you shine light on any sort of visible object, you are constantly bombarding it with energy which fuels the reflection (return emission of light and heat). A desk "stays brown" by the process of absorbing and re-emitting the energy that you are introducing into the system by having light shine on it.

Answer 4

The electrons get excited by light rays coming at them. They then raise to a higher energy level, and drop back down, emitting light. At this point, the exact same thing happens again. And again. And again...

Voila, your desk continues to look brown.

Answer 5

your thinking to much on the electrons orbiting..they are so small to us they arent orbiting,just there...Electrons absorb photons from white light which has all colors in the spectrum...depending on the energy level of the electrons depends what colors they absorb,what ever color they dont absorb is what the color is they emit and give that matter that color...When they absorb photons they get excited and jump to a higher orbit then fall back is when they emit a color

Answer 6

color is not so much about the electrons as it is about the human eye. light has frequency, however fast or slow the frequency determines the color interpretted by our eyes. there would be no color if there were no difference in frequency of light. :) you ask all the smart questions. i remember thinking about this stuff before...