I believe this question will be a no-brainer for many members. I want to conceptually grasp how do atoms (and molecules) behave using QM in contrast to the classical physics model. Now there's uncertainty principle and atoms don't have a fixed position and momentum, and that's fine, I know it's not entirely correct but I imagine it in a wave-like way where they are spread out in space and mutually interacting. Please correct me if I'm wrong. Now for instance the atoms in a solid are tightly packed, does this mean that the atoms (which are 'wavy') mutually overlap in space and get entangled, or do they cancel each other out in a way that they occupy a specific region of space where we can find them but do not overlap with other atoms? I hope my question is clear so it can be described how is the atomic behavior in everyday objects (not in isolation and cold temperatures) different in the quantum picture than in the classical picture. Regards.