Structure Of Atom

The wave function $(\Psi)$ of $2 \mathrm{~s}$ is given by


\(\Psi_{2 \mathrm{~s}}=\frac{1}{2 \sqrt{2 \pi}}\left(\frac{1}{a_0}\right)^{1 / 2}\left(2-\frac{r}{a_0}\right) e^{-r / 2 a_0}\)


At $r=r_0$, radial node is formed. Thus, $r_0$ in terms of $a_0$