Question

Which of the following leads to bonding?

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

Orbitals forming a bond should have the same sign (phase) and orientation in space.
Also, the orbitals should have the same or nearly the same energy and the same symmetry around the molecular axis for proper orbital overlapping to take place. Hence, only $s$ and $p_z$ (considering z-axis as internuclear axis) will lead to formation of $\sigma$ bond.