Considering x-axis as the internuclear axis which out of the following will not form a sigma bond and why?
A. 1s and 1s
B. 1s and 2px;
C. 2py and 2py
D. 1s and 2s.
2py and 2py orbitals will not a form a sigma bond. Taking x-axis as the internuclear axis, 2py and 2py orbitals will undergo lateral overlapping, thereby forming a pi bond.