Lithium is the lighest alkali metal but in aqueous solution , `Li^(+)` has the lowest mobility among alkali metals . Why so ?

Explanation

**Step-by-Step Solution:**

1. **Identify Lithium's Position in the Periodic Table**: Lithium (Li) is the lightest alkali metal and belongs to Group 1 of the periodic table, specifically in Period 2.

2. **Understand the Concept of Mobility in Aqueous Solution**: Mobility refers to the ability of ions to move through a solution. In aqueous solutions, ions are surrounded by water molecules, which can affect their movement.

3. **Analyze Lithium's Size**: Lithium is the smallest alkali metal in terms of atomic radius. Its small size contributes to its unique behavior in solution.

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