Which of the following molecules contain one lone pair of electrons on the central atom?

In case of PH₃  Total no.of electrons should present in PH₃  molecule for completing octet (T) = 1× 8 + 3 × 2 = 14  Total no.of valancy electrons present in PH₃  molecule (V) = 1×5+3 = 8 No.of bonded electrons (T–V) = 14–8 = 6 (3 bond pairs No.of nonbonded electrons  = {V–(T–V)} = 8–6 = 2(1 lone pair) PH₃ has one lone pair of electrons and similarly H₂S has two lonepairs on central atom by lewis concept