What the difference between an orbit in the Bohr model and an orbital in the quantum mechanical model of the atom?

Answer 1

The original Bohr orbits were circular. Sommerfeld added ellipticity and both of these were modeled after the solar system of the sun and planets. The quantum mechanical model has no structure in the sense that it behaves as the solar system or any other model with which we may be familiar. It is based strictly on mathematics. The atom is defined in terms of a mathematical term as is each orbit, etc.