`Li^(2+) and He^+` ions have spectrum similar to ________ atom.

Explanation

To determine which atom has a spectrum similar to the ions \( \text{Li}^{2+} \) and \( \text{He}^+ \), we can follow these steps:

### Step 1: Identify the number of electrons in each ion
- **For \( \text{Li}^{2+} \)**: Lithium has an atomic number of 3, meaning it has 3 electrons. When it loses 2 electrons to become \( \text{Li}^{2+} \), it has:
\[ 3 - 2 = 1 \text{ electron} \]

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