The set representing correct order of `IP_(1)` is

Options

A. K `gt` Na `gt` Li
B. Be `gt` Mg `gt` Ca
C. B `gt` C `gt` N
D. Fe`gt` Si`gt` C

Answer

To determine the correct order of first ionization potential (IP₁) for the given elements: Potassium (K), Sodium (Na), Lithium (Li), Beryllium (Be), Magnesium (Mg), and Calcium (Ca), we need to consider the trends in the periodic table regarding ionization energy.

### Step-by-Step Solution:

1. **Understand Ionization Potential**:
- Ionization potential (or ionization energy) is the energy required to remove the most loosely bound electron from an atom in its gaseous state.

2. **Identify the Groups and Periods**:
- Potassium (K), Sodium (Na), and Lithium (Li) are in Group 1 (alkali metals).
- Beryllium (Be), Magnesium (Mg), and Calcium (Ca) are in Group 2 (alkaline earth metals).

3. **Trends in Ionization Energy**:
- **Down a Group**: As you move down a group in the periodic table, the size of the atom increases due to the addition of electron shells. This results in a decrease in ionization potential because the outermost electron is further from the nucleus and is less tightly held.
- **Across a Period**: As you move from left to right across a period, the ionization potential generally increases due to increasing nuclear charge which pulls the electrons closer to the nucleus.

4. **Evaluate the Elements**:
- For Group 1 (Li, Na, K):
- Lithium (Li) has the highest ionization potential, followed by Sodium (Na), and then Potassium (K).
- For Group 2 (Be, Mg, Ca):
- Beryllium (Be) has the highest ionization potential, followed by Magnesium (Mg), and then Calcium (Ca).

5. **Combine the Trends**:
- From the above evaluations, we can summarize:
- Li > Na > K (for Group 1)
- Be > Mg > Ca (for Group 2)

6. **Final Order of Ionization Potential**:
- Combining both groups, the overall order of ionization potential from highest to lowest is:
- Be > Li > Mg > Na > Ca > K

### Conclusion:
The correct order of first ionization potential (IP₁) is:
**Be > Li > Mg > Na > Ca > K**