When half-filled valence orbital of one atom overlaps with half-filled valence orbital of other atom, a covalent bond is fonned. Head on or axial overlap leads to the fonnation of sigma bond. Sidewise or lateral overlap of atomic orbitals (p) give rise to the formation of pi-bond. Similarly side wise overlap between d-orbitals can lead to the fomation of delta-bond. In case of pi -bond, the probability of finding the shared electron cloud is zero along the line joining two nuclei while ithe probability of finding the shared electron cloud is maximum along the inter nuclear axis. The strength of bonds by s-s, p-p, s-p overlap is in the order :

When half-filled valence orbital of one atom overlaps with half-filled

1.	When half-filled valence orbital of one atom overlaps with half-filled valence orbital of other atom, a covalent bond is fonned. Head on or axial overlap leads to the fonnation of sigma bond. Sidewise or lateral overlap of atomic orbitals (p) give rise to the formation of pi-bond. Similarly side wise overlap between d-orbitals can lead to the fomation of delta-bond. In case of pi -bond, the probability of finding the shared electron cloud is zero along the line joining two nuclei while ithe probability of finding the shared electron cloud is maximum along the inter nuclear axis. The strength of bonds by s-s, p-p, s-p overlap is in the order :
Answer» `s-s LT s-p lt p-p ` `s-s lt p-p lt s-p ` `s-p lt s-s lt p-p ` `p-p lt s-s lt s-p ` ANSWER :A