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 trend.
Ionization energy increases across a period (from left to right) because the atomic size decreases, leading to a stronger attraction between the nucleus and the electrons. Ionization energy decreases down a group because the outermost electrons are farther from the nucleus and more shielded by inner electrons.
Step 2: Analyze the elements.
- Lithium (Li) has the lowest ionization energy because it is in Group 1.
- Boron (B) has a higher ionization energy than Li but less than Be and C.
- Beryllium (Be) has a higher ionization energy due to its stable \(s^2\) electron configuration.
- Carbon (C) has the highest ionization energy because it is farther across the period and has a relatively small atomic size.
Step 3: Conclusion.
The order of increasing first ionization energy is: \[ \text{Li}<\text{B}<\text{Be}<\text{C} \]
Final Answer: \[ \boxed{\text{(C), (B), (A), (D)}} \]