Question

Which of the following species are expected to have spectrum similar to hydrogen?

• A. ${He}^{+}$
• B. ${He}^{2+}$
• C. ${Li}^{2+}$
• D. ${Li}^{+}$

Answer 1

Answer: (A), (C)

The correct options are
A ${He}^{+}$
C ${Li}^{2+}$

${He}^{+}$ and $L{i}^{2+}$ are one electron species. They will have spectrum similar to hydrogen which is also one electron species.

$H{e}^{2+}$ and $L{i}^{+}$ are not one electron species. Hence, they will not have a spectrum similar to hydrogen.