The spectrum of `He` is expected to be similar to.

Options

A. `Li^(+)`
B. `He`
C. `H`
D. `Na`

Explanation

To determine which atom or ion has a spectrum similar to that of helium, we need to consider the number of electrons in each species.

### Step-by-Step Solution:

1. **Identify the number of electrons in helium (He)**:
- Helium has 2 electrons.

2. **Look for other atoms or ions with the same number of electrons**:
- We need to find another species that also has 2 electrons.

3. **Consider the lithium ion (Li⁺)**:
- Lithium (Li) has 3 electrons. When it loses one electron to become Li⁺, it has 2 electrons remaining.
- Therefore, Li⁺ has the same number of electrons as He.

4. **Compare the electronic configurations**:
- The electronic configuration of helium (He) is 1s².
- The electronic configuration of lithium ion (Li⁺) is also 1s², as it has lost one electron from its original configuration of 1s² 2s¹.

5. **Conclusion**:
- Since both helium and lithium ion have the same number of electrons and the same electronic configuration, their spectra are expected to be similar.
- Thus, the spectrum of helium is expected to be similar to that of lithium ion (Li⁺).

### Final Answer:
The spectrum of helium (He) is expected to be similar to that of lithium ion (Li⁺).