The energy of an electron in the ground state $(n=1)$ for $\mathrm{He}^{+}$ion is $-x J$, then that for an…

The energy of an electron in the ground state $(n=1)$ for $\mathrm{He}^{+}$ion is $-x J$, then that for an electron in $n=2$ state for $\mathrm{Be}^{3+}$ ion in J is
  1. $-\frac{x}{9}$
  2. $-4 x$
  3. $-\frac{4}{9} \mathrm{x}$
  4. $-x$

Solution

$E_n=-R_H\left(\frac{z^2}{n^2}\right) J$ For $\mathrm{He}^{+}(n=1)$, $\begin{aligned} & E_n=-x=-R_H\left(\frac{2^2}{1^2}\right)=-4 R_H \\ & \therefore \quad R_H=\frac{x}{4} \\ & \end{aligned}$ For $\mathrm{Be}^{3+}(n=2)$, $\begin{aligned} E_n & =-R_H\left(\frac{z^2}{n^2}\right) J \\ & =-\frac{x}{4} \times\left(\frac{4 \times 4}{2 \times 2}\right)=-x J \end{aligned}$

Asked in: NEET 2024

Practice more Structure of Atom questions on Aicharya