Question

Strongest bond is formed by the head-on overlapping of:

• A. 2s and 2p orbitals
• B. 2p and 2p orbitals
• C. 2s and 2s orbitals
• D. All of these

Answer 1

The correct option is B

2p and 2p orbitals

Explanation for correct option

Option B : 2p and 2p orbitals

• Pi bonds are actually formed by the orbital overlap of the $\mathrm{p}-\mathrm{p}$ orbitals .
• Also the electron density is the highest along the axis of the strongest bond.
• Which is formed when the head on overlapping of the $2\mathrm{p}-2\mathrm{p}$ orbitals take place.
• 

Explanation for incorrect options :

Option A: $2\mathrm{s}\mathrm{and}2\mathrm{p}$ orbitals

• In this type of bonding no greater extent of overlapping is achieved .
• So a comparatively weak bond is formed .
• 
• Thus option (A) is incorrect.

Option C: 2s and 2s orbitals

• When the two half-filled s-orbitals of the two different atoms containing unpaired electrons with the opposite spin will overlap, there would be the formation of this overlapping.
• This $2\mathrm{s}-2\mathrm{s}$ overlap is stronger than the $2\mathrm{s}-2\mathrm{p}$ one but not more than the $2\mathrm{p}-2\mathrm{p}$ one.
• 
• Thus option (C) is incorrect.

Option D: All of these

• Since the other two options mentioned earlier are incorrect
• Thus this will also be an incorrect option

Hence , Strongest bond is formed by the head-on overlapping of $2\mathrm{p}-2\mathrm{p}$