Question

25. Which of these molecules does not satisfy octet
rule
(a) H2
(b)N2
(c) O2
(d) HCN​

Answer 1

Answer:

All the three molecules SF

6

,PCl

5

andBrCl

5

deviate from the octet rule, as the central atom in them contains more than 8 electrons. Thus, this is an example of expanded octet.

The central atom in SF

6

has 12 valence electrons.

The central atom in PCl

5

has 10 valence electrons.

The central atom in BrCl

5

has 12 valence electrons.

However, according to Sugden's view of singlet linkage, the octet rule is never violated but in certain molecules, the atoms are linked not only by covalent bonds but also by singlet linkage (half bond or single electron linkage).

Thus, in SF

6

, there are 2 covalent bonds and 4 singlet linkages. Thus, the S atom and six F atoms in SF

6

contain 8 electrons each.