The plot of orbital wave function $\mathrm{\psi }\left(\mathrm{r}\right)$ as a function of distance r of the electron from the nucleus for 2s orbital is

Plots of (a) and (c) are the orbital wave function $\mathrm{\psi }\left(\mathrm{r}\right)$ (for 15825) while (b) and (d) are the variation of probability density ${\mathrm{\psi }}^2\left(\mathrm{r}\right)$ as a function of distance (r) of the electron from the nucleus for ls and 2s orbital.

For ls orbital the probability density is maximum at the nucleus and it decreased sharply as we move away from it. For 2s orbital the probability density first decreases sharply to zero and then starts increasing. After reaching maxima it decreases again and approaches zero as the value of r increases further.