The atomic size of lithium is ________ than that of sodium. (greater/smaller).

Explanation

To determine the atomic size of lithium compared to sodium, we can follow these steps:

### Step-by-Step Solution:

1. **Define Atomic Size**:
- Atomic size (or atomic radius) is defined as the distance from the nucleus of an atom to the outermost shell of electrons.

2. **Identify the Group**:
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