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 among the elements Boron (B), Aluminium (Al), Magnesium (Mg), and Potassium (K), 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). The more easily an element can lose an electron, the more metallic it is.

### Step 2: Position in the Periodic Table
- **Boron (B)**: Located in Group 13 and Period 2.
- **Aluminium (Al)**: Located in Group 13 and Period 3.
- **Magnesium (Mg)**: Located in Group 2 and Period 3.
- **Potassium (K)**: Located in Group 1 and Period 4.

### Step 3: Trends in Metallic Character
- **Across a Period**: Metallic character decreases from left to right. This is because as you move across a period, the nuclear charge increases, making it harder to lose electrons.
- **Down a Group**: Metallic character increases as you move down a group. This is due to the increase in atomic size and the decrease in ionization energy, making it easier to lose electrons.

### Step 4: Analyze the Elements
- **Potassium (K)**: Being in Group 1 and Period 4, it has the highest metallic character because it can easily lose one electron.
- **Magnesium (Mg)**: In Group 2 and Period 3, it has a lower metallic character than potassium but higher than aluminium and boron.
- **Aluminium (Al)**: In Group 13 and Period 3, it has a lower metallic character than magnesium.
- **Boron (B)**: Being in Group 13 and Period 2, it has the lowest metallic character among these elements.

### Step 5: Order of Metallic Character
Based on the analysis:
1. Potassium (K) - Highest metallic character
2. Magnesium (Mg)
3. Aluminium (Al)
4. Boron (B) - Lowest 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**