Question

The strength of sigma bonds formed by the axial overlap of $s$ - or $p$ - orbitals of $2^{nd}$ shell of the participating atoms decreases as:

• A. $s-s>p-s>p-p$
• B. $s-s>p-p>s-p$
• C. $p-s>s-s>p-p$
• D. $p-p>s-p>s-s$

Answer 1

Correct option: (D)

• The strength of sigma bonds formed by the axial overlap of orbitals​ depends upon the extent of overlapping between orbitals.
• $p-$ orbitals have more axial electron density as compared to $s-$ orbitals due to their dumb-bell shape.
• So, due to more axial electron density, the sigma bond formed by the $p-$ orbital overlapping is strong as compared to the sigma bond formed by $s-$ orbitals.
• Hence, strength of sigma bond in decreasing order: $p-p>s-p>s-s$

Hence, the correct option is (D).