Chemists usually build mathematical models of molecular orbitals by combining atomic orbitals. Hybrid orbitals from each atom of the molecule, or other molecular orbitals from groups of atoms can also be used. Computers can work on these functions. Molecular orbitals allow chemists to apply quantum mechanics to study molecules. MOs answer questions about how the atoms in molecules stick together. The various rounded shapes in an orbital diagram indicate where electrons would most likely be found in an atom. 