$\text { Among the following, the correct statement is }$

• A

  For $\Psi(\mathbf{r})$ denoting the normalized wavefunction of a one-electron system, the value of $|\Psi(\mathbf{r})|^2$ at any point $\mathbf{r}$ cannot exceed one since the integral of $|\Psi(\mathbf{r})|^2$ over the whole space is one.
• B

  $\text { The ionization potential of } \mathrm{He} \text { atom is greater than that of } \mathrm{He}^{+} \text {ion. }$
• C

  If the ionization potential of the hydrogen atom is 13.6 eV , the first excited state energy of the $\mathrm{He}^{+}$ion will be 13.6 eV .
• Correct answer
  D

  According to the prediction of simple molecular orbital theory, the bond orders of $\mathrm{He}_2^{+}$ion and $\mathrm{H}_2^{+}$ion are the same.

Hence, the correct answer is option: 'D'.