The shapes of the atomic orbitals are very important because covalent chemical bonds depend on the sharing of the electron that occupy these orbitals.
The shape of an atomic orbital is determined primarily by l, the angular momentum quantum number. Recall that each value of l is assigned a letter that corresponds to particular orbitals. For example, the orbitals with (l=0) are called s orbitals; those with (l=1), p orbitals; those with (L=2), d orbitals, etc. We now will examine the shape of each of these orbitals.
S Orbitals (l=0)
Anatomic orbital can also be represented by a geometrical shape that encompasses the volume where the electron is likely to be found most frequently-typically, 90% of the time. For example, the 1s orbital can be represented as three-tridimensional sphere as show in the figure 1.
Each s orbital can contain at least 2 electrons.
The spherical symmetrical 1s orbital is the lowest energy orbital.
p Orbitals (l=1)
Any principal level with n=2 or higher contains three p orbitals (ml= -1, 0, +1). The p orbitals are not spherical symmetrical like the s orbital, but they have two lobes of electron density on either side of the nucleus and a node located at the nucleus. The three p orbitals differ only in their orientation and are orthogonal to one another. It is convenient to define an x, y, and z axis system and then label each p orbital as px, py and pz. The 3p, 4p, 5p, and higher p orbitals are all similar in shape to the 2p orbitals, but they contain additional nodes (as same as higher s orbitals) and are progressively larger in size.
Each p orbital can contain 2 electrons, so it can contain 6 electrons in total.
d Orbitals (l=2)
Each principal level with n=3 or greater contains five d orbitals (ml= -2, -1, 0, +1, +2).Four of these orbitals have a cloverleaf shape, with four lobes of electron density around the nucleus and two perpendicular nodal plates. Th dxy, dxz, and dyx orbitals are oriented along the xy, xz, ans yz planes, respectively, and their lobes are oriented between the corresponding axes. The 4d, 5d, 6d, and higher d orbitals are all similar in shape to the 3d orbitals, but they contain additional nodes and are progressively larger in size.
f Orbitals (l=3)
Each principal level with n=4 os higher contains seven f orbitals (ml= -3, -2,-1, 0, +1 , +2, +3). These f orbitals have more lobes and nodes than d orbitals.