Two elements M and N belonge to group I and II respectively and are in the same period of the periodic table. How do the following properties of M and N vary ?
Sizes the their atoms

Explanation

To determine how the sizes of the atoms of elements M and N vary, we can follow these steps:

### Step 1: Identify the Groups and Periods
- Element M belongs to Group I (alkali metals).
- Element N belongs to Group II (alkaline earth metals).
- Both elements are in the same period of the periodic table.

**Hint:** Remember that elements in the same period have the same number of electron shells.
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