Orbital Theory

Name:
Orbital Theory
Detailed information:
The quantum theory of matter applied to the nature and behavior of the electron either in a single atom (atomic orbital) or combined atoms (molecular orbital). A combination of Schrodinger's wave mechanics and Heisenberg's uncertainty principle, the orbital theory was formulated in 1926. It has yielded a better understanding of the electron and its critical part in chemical bonding than is possible with Newtonian mechanics. In simple language, the orbital theory considers the electron not as a particle but as a three-dimensional wave that can exist at several energy levels; its exact location and position in the “shell” (which in most elements is a group of orbitals) cannot be precisely determined but only predicted by the laws of mathematical probability. The orbital levels and the movement of electrons within them are expressed by wave functions and quantum numbers. The probability that an electron will be found in a given volume (i.e., the square of the one-electron wave function) is called the orbital of that electron, and the shape of the orbital is defined by surfaces of constant probability (i.e., spheres and elliptically shaped doughnuts). The electron orbital, described in terms of probability, is like a cloud, with indefinite boundaries. The energy state of each electron is given by four quantum numbers that describe its principal level, its angular momentum, its magnetic moment, and its spin. This concept has exerted a profound effect on modern ideas about chemical bonding, transition metal complexes, semiconductors, and solid-state physics.