Final answer:
Erwin Schrödinger discovered the quantum-mechanical model of the atom, which explained the behavior of electrons as particles and waves and superseded Bohr's model.
Step-by-step explanation:
Bohr's model of the atom was based on classical mechanics and the notion of precise orbits, which was later found to be flawed in the microscopic domain. However, Erwin Schrödinger extended the work of de Broglie and derived the Schrödinger equation, which described electrons as three-dimensional stationary waves or wavefunctions. This new model, known as the quantum-mechanical model, explained the behavior of electrons as both particles and waves, and it superseded Bohr's model.