Hydrogen atom energy level
From the Bohr theory:
$$\large E=-\frac{Z^2e^4m}{8\epsilon_0^2n^2h^2}=-13.6\times\frac{Z^2}{n^2}\ \mathrm{eV}$$
where:

$$\begin{array}{c|c|}
&amp; Z&amp;\text{atomic number}&amp;-\\
&amp; e&amp;\text{charge of electron}&amp;1.60 \times 10^{-19}\ \mathrm{C}\\
&amp; m&amp;\text{mass of electron}&amp;9.10 \times 10^{-31}\ \mathrm{kg}\\
&amp; \epsilon_0&amp;\text{electric permittivity}&amp; 8.85 \times 10^{−12}\ \mathrm{F/m}\\
&amp; n&amp;\text{principal quantum number}&amp;-\\
&amp; h&amp;\text{Planck's constant}&amp;6.62 \times 10^{-34}\ \mathrm{m^2\ kg/s}\\
\end{array}$$

You can put values of $Z$ and $n$ for any shell of a hydrogenic species like $\ce{H}$, $\ce{He+}$, $\ce{Li^2+}$, $\ce{Be^3+}$, $\ce{B^4+}$…