Question

The octet rule is not valid for which of the following molecules?

• A. $C{O}_2$
• B. $H_{2}O$
• C. $O_2$
• D. $NO$

Answer 1

The correct option is D $NO$

In carbon dioxide, water and oxygen, the octet rule are obeyed. Each of these molecules has $8$ electrons on the central atom.

However, in $NO$, the octet rule is not valid as it is an odd electron molecule.

Nitrogen has 5 valence electrons and oxygen has $6$ valence electrons.

Hence, the correct option is $\text{D}$