Are there any physical processes of which we have a full understanding? Are there any physical processes of which we have a full understanding? For instance, we know that each orbit has a different energy, and electrons can move to a higher orbit by absorbing energy and drop to a lower orbit by emitting energy. However, do we understand everything related to atomic orbits? For example, what determines the shape of the orbits, do orbits sometimes change shape, is it fixed, do they cross each other, do they change depending on the proximity of other atoms or electrons? How much is there to learn about simple physical concepts and processes related to atomic orbits?
Is there a concept related to the lack of knowledge we have of just about anything related to physics outside of maybe classical physics (I am assuming we understand 99% of everything related to processes in classical physics)?
 A: 
Is there any physical processes over which we have full understanding of?

Only if physics ever reaches the level of having a Theory Of Everything) TOE, one will be able to answer in the affirmative. At present physics knowledge is encapsulated in different theoretical models valid for specific variables and phase space. Depending on the values of the variables, different mathematical theoretical models fit the data and are predictive of new.
Atoms are in the dimensions that necessitate quantum mechanics, and the quantum mechanical models have progressed from the simple Bohr model you assume. There are no orbits but orbitals, as a comment says, i.e. probability loci that have little to do with the concept of classical orbits, which was useful before theory progressed.
The physics models we have blend mathematically correctly in the overlap region of the variables, but certainly we cannot speak of full understanding when we are peeling the onion in the microcosm and trying to fit quantized gravitational models to cosmological data.
A: I think, that at any level of theoretical and experimental progress one can doubt, whether the current theory provides an exhaustive and complete description of the observed phenomena. At the present time, we are sure that the Standart Model, being the most complete verified theory describing our world, is not complete due to the several paradoxes - like the famous fine-tuning problem, the problem of incorporating gravity, neutrino oscillations and e.t.c.
However, even if there was a theory, that could explain everything observed in nature, one may still hesitate to affirm that it is actually a TOE. Maybe there are new phenomena beyond the current level of experimental devices precision.
And concerning the orbitals, as the comment and anna's answer mentions, it is not a trajectory along which the particle moves, it is an amplitude probability, and the shape arises simply as a decomposition in spherical harmonics.
A: I agree totally with anna v's answer but I thought I would give a slightly more philosophical answer. I take the words "full understanding of physics phenomena" to mean a complete theoretical description.
In most of natural sciences and in particular in physics we can never prove a theory in a way akin to how mathematicians prove a theorem. At best we can say that a theory agrees with all valid experimental evidence within the uncertainty of measurement and statistics. We can say that there is an enormous amount of experimental evidence that agrees with the theory. On the contrary it is relatively easy to disprove theories.
A very good example is the understanding of elementary particles, and in particular electrons (Quantum Electrodynamics or QED). QED and experiment agrees on the value of a constant (so-called anamolous magnetic dipole moment of electron) up to 1 part in billion (see Wikipedia). This sounds like a full understanding of QED. However, we know that there are several (somewhat technical) things that are terribly wrong with QED that hint that QED cannot be a full understanding.
Imagine a child that keeps asking the question "why" all the time. At some point parents usually say something like "well because it is". Scientists are similar we keep asking "why" all the time but we do not allow the parent's answer. It is very hard to imagine that those "why" questions will end soon and unless the why questions end on a mathematical truth it's hard to imagine that we will have a "full" understanding of a phenomena.
A: No for philosophical reasons.
The closest science can come to knowing fundamentally reality would be a Theory of Everything. But TOE's are a dime a dozen. It-from-bit, constructor theory, mathematical universe, geometric unity. None of them make unique predictions, or ones we could test.
Science can just make more accurate and accurate models. Of course having a TOE that explains everything makes it tempting to say you know what is real, but even then as finite beings you could argue we can only test a finite number of times! Let alone the uniqueness problem above.
