Concept of ORBITALS

According to Heisenberg's Uncertainty Principle, it is not possible to determine precisely the position and momentum of an electron in the atom simultaneously. Therefore, Bohr's concept of well defined orbits is ruled out. According to quantum mechanics the probability of finding an electron does not become zero even at large distances from the nucleus. Therefore it is not possible to draw a boundary that will enclose the region of 100% probability. However, for the sake of simplicity arbitrary boundaries are drawn which encloses the region where probability of finding the electron is maximum, this region is known as an Orbital. Thus, An orbital may be defined as the region of space around the nucleus where the probability of finding an electron is maximum.