Question

Considering x-axis as the internuclear axis, which out of the following will not form a sigma bond
and why ? `(a) s and 1s (b) 1s and 2p_(x) (c) 2p_(y) and 2p_(y)` (d) 1s and 2s`.

Answer 1

Only (c) will not form a `sigma ` - bond because taking x-axis as the intermolucular axis , there will be lateral
(sideway) overlap between the two ` 2p_(y)` orbitals forming `pi` bond .