Question

Which of the following does not obey octet rule?

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

Answer 1

The correct option is C $NO$

In $NO$, nitrogen has 5 valence electrons and oxygen has 6 valence electrons. The nitrogen atom can share at most two electrons with the oxygen atom. Therefore, it is left with 3 valence electrons in its outermost shell. So, only the octet of oxygen atom is achieved. Hence, it does not obey the octet rule completely.