Shapes of s orbitals

s orbitals are non-directional and spherically symmetrical, This means that the probability of finding the electron is same in all directions at a particular distance from the nucleus, The 1s orbital is shown in the figure 1.3.

fig 1.3 - Shapes of 1s and 2s orbitals

It is observed that density of charge cloud is maximum at the nucleus and decreases with increase in distance from the nucleus. The 2s orbital is also non-directional and spherically symmetrical. In this case, the density is maximum at the nucleus and becomes small at large distances. However, the effective volume or size of 2s is larger than 1s orbital. An important feature of 2s orbital is that there is a spherical shell within 2s orbital (region without dots) where the probability of finding the electron is practically zero, This is called a node or a nodal surface. Thus, a 2s orbital differs from 1s orbital in being larger in size and having a nodal surface. The higher s orbitals have also spherical shapes and number of nodal surfaces in s orbital for any given energy level is n - 1, where n represents energy level.