Which of the following represents the correct order of metallic character of the given elements?

Options

A. `Be lt Si lt Mg lt K`
B. `K lt Mg lt Be lt Si`
C. `Be lt Si lt K lt Mg`
D. `Si lt Be lt Mg lt K`

Answer

To determine the correct order of metallic character among the given elements, we need to understand the trends in metallic character across the periodic table.

### Step-by-Step Solution:

1. **Understanding Metallic Character**:
- Metallic character refers to the tendency of an element to lose electrons and form positive ions (cations). Elements that easily lose electrons are considered more metallic.

2. **Periodic Trends**:
- **Left to Right**: As we move from left to right across a period, the metallic character decreases. This is because the effective nuclear charge increases, pulling the electrons closer to the nucleus and making them harder to remove.
- **Top to Bottom**: As we move down a group, the metallic character increases. This is due to the increase in atomic size, which results in outer electrons being farther from the nucleus and more easily lost.

3. **Identifying the Elements**:
- Let's say the elements in question are Potassium (K), Magnesium (Mg), Beryllium (Be), and Silicon (Si).
- Potassium (K) is in Group 1 (alkali metals), Magnesium (Mg) is in Group 2 (alkaline earth metals), Beryllium (Be) is also in Group 2 but is higher in the group than Mg, and Silicon (Si) is in Group 14.

4. **Arranging the Elements**:
- **Potassium (K)**: Most metallic due to being in Group 1 and having one electron in its outer shell. It is also the largest in size among these elements.
- **Magnesium (Mg)**: Next in metallic character as it is in Group 2 and has two electrons in its outer shell.
- **Beryllium (Be)**: Less metallic than Mg because it is smaller and has a higher effective nuclear charge, making it harder to lose its two outer electrons.
- **Silicon (Si)**: Least metallic among these as it is a metalloid and has four electrons in its outer shell, which makes it less likely to lose electrons.

5. **Final Order**:
- The correct order of metallic character from most metallic to least metallic is:
- Potassium (K) > Magnesium (Mg) > Beryllium (Be) > Silicon (Si).

### Conclusion:
The correct order of metallic character for the given elements is **K > Mg > Be > Si**.