optics - Why are objects opaque?

I have been searching the internet for answers to this question, but haven't found a convincing one. I would appreciate any response.

I understand why objects are opaque/black. For example when (white) light is incident on a closed book (let's say it's blue), all wavelengths of visible light except blue are absorbed and hence we see it as blue.

Now, from what I read,

[0.] it is the electrons that absorb the (non-blue) photons from the white light and jump to higher energy states.

My questions are:

1 - Do the electrons stay in the same state?

2 - If they were to jump back to there original state, shouldn't they emit a photon that is exactly of the same wavelength as the one that was absorbed by it in the first place?

3 - If they are in the same state, why does the book continue to appear blue? It can't absorb additional energy unless it returns back to its original state, In doing so won't it emit a photon of the same wavelength it absorbed in the first place?

4 - And , finally, what part of the atom is reflecting the blue light? Is it a bouncing electron?

Answer

If you are not familiar with the subject this link (wiki) can give you a basic knowledge of what happens in a simple atom of H, and then you can expand through related articles.

All your 4 questions are related, and I added [0-] to the statement in your premise:

Photons in all frequencies hitting an object are absorbed in different ways (absorbed, reflected, refracted, scattered, transtormed into thermal energy) by the atoms, not only [0-] by the electrons.

Electrons (1-) do not stay in the same state, they keep jumping up to different levels of excitation and down again to the (2-) original state.

(3-) on their way down they emit all sorts of photons, of different frequencies, as you can see in the link, but usually only one in the visual spectrum. So you see blue because that is the only frequency you can detect. And the light you see comes all the time from different electrons.

(4-) you are right, the light is coming mainly from outer electrons, but it is not mainly reflected. That is what is misleading and confusing you, if the light were reflected you would see all frequencies. The light is emitted and, the frequencies are, so to speak, filtered by the electrons, they absorb all frequencies and return only a few.

I hope I covered all aspects of your doubts