|an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle.|
|the offspring of a zebra and a donkey.|
|1.||of or denoting an orbit|
|2.||(of a motorway or major road circuit) circling a large city|
|3.||a region surrounding an atomic nucleus in which the probability distribution of the electrons is given by a wave function|
|4.||an orbital road|
orbital or·bit·al (ôr'bĭ-tl)
Relating to an orbit.
|orbital (ôr'bĭ-tl) Pronunciation Key
(click for larger image in new window)
A partial description of the quantum state of an electron (or other particle) orbiting the nucleus of an atom. Different orbitals have different shapes and orientations, depending on the energy of the electron, its angular momentum, and its magnetic number. Orbitals have no clear boundaries; the shape of an orbital, as depicted graphically, shows only the regions around the nucleus in which an electron has a relatively high probability of being found. No more than two electrons (each with opposite spin) can coexist in a single orbital because of the Pauli exclusion principle. See also probability wave, quantum number, shell..