Question
Regarding the molecular orbital (MO) energy levels for homonuclear diatomic molecules, the INCORRECT statement(s) is(are)
JEE Advanced
Chemistry
Chemical Bonding and Molecular Structure
2025
JEE Advanced 2025 (Paper 1)
JEE Advanced Chemistry Question (2025) — Solution
Options
- A. Bond order of Ne _2 is zero.
- B. The highest occupied molecular orbital (HOMO) of F_2 is -type.
- C. Bond energy of O _2^ + is smaller than the bond energy of O _2 .
- D. Bond length of Li _2 is larger than the bond length of B _2
Answer
C. Bond energy of O _2^ + is smaller than the bond energy of O _2 .
Step-by-step solution
(i) Ne _2 ( 1 ~s ^2 ) ( ^* 1 ~s ^2 ) ( 2 ~s ^2 ) ( ^* 2 ~s ^2 ) ( 2 p _ z ^2 ) ( 2 p _ x ^2= 2 p _ y ^2 ) ( ^* 2 p _ x ^2= ^* 2 p _ y ^2 ) ( ^* 2 p _ z ^2 ) B.O. = 6-6 2 =0 (ii) F _2 ( 1 ~s ^2 ) ( ^* 1 ~s ^2 ) ( 2 ~s ^2 ) ( ^* 2 ~s ^2 ) ( 2 p _ z ^2 ) ( 2 p _ x ^2= 2 p _ y ^2 ) ( ^* 2 p _ x ^2= ^* 2 p _ y ^2 ) (iii) O _2^ ( 1 s^2 ) ( ^* 1 s^2 ) ( 2 s^2 ) ( ^* 2 s^2 ) ( 2 p_z^2 ) ( 2 p_x^2= 2 p_y^2 ) ( ^* 2 p_x^1= ^* 2 p_y ) B.O. = 6-1 2 =2.5 O _2 ( 1 s^2 ) ( ^* 1 s^2 ) ( 2 s^2 ) ( ^* 2 s^2 ) ( 2 p_ z ^2 ) ( 2 p_ x ^2= 2 p_ y ^2 ) ( ^* 2 p_ x ^1= ^* 2 p_ y ^1 ) B.O. 6-2 2 =2 (Bond order increases, Bond strength increases) (iv) Size of atom increases, Bond length increases Size of Li > B So, Bond length of Li _2> B _2
Related: Chemistry — Chemical Bonding and Molecular Structure · All PYQ Banks