Arrange the elements: B, Al, Mg and K in the decreasing order of metallic character.

Explanation

To arrange the elements B (Boron), Al (Aluminum), Mg (Magnesium), and K (Potassium) in decreasing order of metallic character, we can follow these steps:

### Step 1: Understand Metallic Character
Metallic character refers to the tendency of an element to lose electrons and form positive ions. Elements with higher metallic character are more likely to lose electrons.

### Step 2: Identify the Groups of the Elements
- Boron (B) and Aluminum (Al) belong to Group 13 (P-block).
- Magnesium (Mg) belongs to Group 2 (S-block).
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