Subject: How do atoms of an object absorb or reflect photons/light to give color?

I submitted this question before and was referred to two other questions 
that came close to asking what I already have but without an answer as 
detailed as I am asking.

My original question was:

How do atoms of an object absorb or reflect photons/light to give color?
At a sub-atomic level, why/how do the atoms that make up objects cause the 
photons that 'hit' them to either be absorbed or reflected making it 
possible for the objects to appear as a color?  ....shortened due to word 
limit request...

The answers to the other questions basically explained that certain 
molecules reflect or absorb different wavelenghts of light.  I know that.  
What I want to know is....WHY?  At an atomic level, what happens to a 
photon(s) that causes it to either be absorbed or reflected by different 
atoms of different molecules?  

In one of the other answers, I understand now that shapes of molecules can 
have an effect, referring to certain butterfly wings, etc., but I would 
like to disclude this particular phenomena from my question.

Thank you.

Re: How do atoms of an object absorb or reflect photons/light to give color?