Considering the elements `B, Al, Mg` and `K`, the correct order of their metallic character is

Options

A. `B gt Al gt Mg gt K`
B. `Al gt Mg gt B gt K`
C. `Mg gt Al gt K gt B`
D. `K gt Mg gt Al gt B`

Explanation

To determine the correct order of metallic character for the elements B (Boron), Al (Aluminium), Mg (Magnesium), and K (Potassium), 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 (cations). Elements with higher metallic character are more likely to lose electrons easily.

### Step 2: Periodic Trends
- **Across a Period**: As we move from left to right across a period in the periodic table, the metallic character decreases. This is because the effective nuclear charge increases, attracting the valence electrons more strongly and making it harder to lose them.
- **Down a Group**: As we move down a group, the metallic character increases. This is due to the increase in atomic size, which makes it easier for the outermost electrons to be lost.

### Step 3: Analyze the Given Elements
- **Boron (B)**: Located in Group 13, Period 2. It is a metalloid and has a relatively low metallic character.
- **Aluminium (Al)**: Located in Group 13, Period 3. It is a metal and has a higher metallic character than Boron.
- **Magnesium (Mg)**: Located in Group 2, Period 3. It is a metal and has a higher metallic character than Aluminium.
- **Potassium (K)**: Located in Group 1, Period 4. It is an alkali metal and has the highest metallic character among these elements.

### Step 4: Order the Metallic Character
Based on the above analysis, we can arrange the elements in order of increasing metallic character:
1. Boron (B) - least metallic character
2. Aluminium (Al)
3. Magnesium (Mg)
4. Potassium (K) - most metallic character

Thus, the correct order of metallic character is:
**K > Mg > Al > B**

### Final Answer
The correct order of metallic character for the elements B, Al, Mg, and K is:
**K > Mg > Al > B**