As we move down the group, the atomic size increases or decreases ?

Explanation

**Step-by-Step Solution:**

1. **Understanding Atomic Size**: Atomic size refers to the distance from the nucleus of an atom to the outermost shell of electrons. It is typically measured in picometers (pm) or angstroms (Å).

2. **Periodic Trends**: In the periodic table, atomic size is influenced by two main factors: the number of electron shells and the effective nuclear charge.

3. **Moving Down a Group**: When we move down a group in the periodic table (for example, from lithium to sodium to potassium), we are adding additional electron shells. Each new element in a group has one more electron shell than the previous element.

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