Orbital models are scientific representations that describe the regions around an atom's nucleus where electrons are likely to be found. Unlike earlier models that depicted electrons as particles in fixed orbits, orbital models illustrate electrons as existing in "clouds" or "orbitals" with specific shapes and energy levels. These shapes can be spherical, dumbbell-like, or more complex, depending on the energy state of the electron. The most commonly referenced orbital model is the quantum mechanical model, which is based on principles of quantum mechanics. This model uses mathematical equations to predict the probability of finding an electron in a particular region, providing a more accurate understanding of atomic structure compared to previous models like the Bohr model.