Question

Arrange the following in the order of increasing first ionization energy
(A) Beryllium (Be)
(B) Boron (B)
(C) Lithium (Li)
(D) Carbon (C)
Choose the correct answer from the options given below:

• A. (A), (B), (C), (D).
• B. (C), (B), (A), (D).
• C. (B), (A), (D), (C).
• D. (D), (B), (A), (C).

Hint:

Ionization energy increases across a period and decreases down a group.

Answer 1

The Correct Option is B

Step 1: Ionization Energy Trends.
Ionization energy generally increases from left to right across a period due to decreasing atomic size and stronger nuclear attraction. Conversely, it decreases down a group as outermost electrons are further from the nucleus and shielded by inner electrons.
Step 2: Element Analysis.
- Lithium (Li) exhibits the lowest ionization energy as it belongs to Group 1.
- Boron (B) has a higher ionization energy than Li, but lower than Be and C.
- Beryllium (Be) demonstrates a higher ionization energy owing to its stable \(s^2\) electron configuration.
- Carbon (C) displays the highest ionization energy due to its position further across the period and smaller atomic size.
Step 3: Conclusion.
The increasing order of first ionization energy is: \[\text{Li}<\text{B}<\text{Be}<\text{C}\]
Final Answer: \[ \boxed{\text{(C), (B), (A), (D)}} \]