the electron is, %? The answer to this question is that the probability density | ψ | has always some value, howsoever small it may be, at any finite distance from the nucleus. It is therefore, not possible to draw a boundary surface diagram of a rigid size in which the probability of finding the electron is %. Boundary surface diagram for a s orbital is actually a sphere centred on the nucleus.
In two dimensions, this sphere looks like a circle. It encloses a region in which probability of finding the electron is about %. Thus, we see that s and s orbitals are spherical in shape. In reality all the s -orbitals are spherically symmetric, that is, the probability of finding the electron at a given distance is equal in all the directions.
It is also observed that the size of the s orbital increases with increase in n , that is, s > s > s > s and the electron is located further away from the nucleus as the principal quantum number increases. Boundary surface diagrams for three p orbitals ( l = ) are shown in Fig. . .
In these diagrams, the nucleus is at the origin. Here, unlike s -orbitals, the boundary surface diagrams are not spherical. Instead each p orbital consists of two sections called lobes that are on either side of the plane that passes through the nucleus. The probability density * If probability density | ψ | is constant on a given surface, | ψ | is also constant over the surface.
The boundary surface for | ψ | and | ψ | are identical. Fig. . Boundary surface diagrams of the three 2p orbitals.
Fig. . (a) Probability density plots of 1s and 2s atomic orbitals. The density of the dots represents the probability density of finding the electron in that region.
(b) Boundary surface diagram for 1s and 2s orbitals. function is zero on the plane where the two lobes touch each other. The size, shape and