Question

part 1 (1 point) complete both resonance structures of nitrous acid, hno2 by adding the missing lone pair electrons, multiple bonds, and non - zero formal charges. do not add curved arrows, reaction arrows, or plus signs between the structures. see periodic table see hint

Explanation:

Step1: Calculate valence - electrons

Nitrogen has 5 valence electrons, oxygen has 6 valence electrons, and hydrogen has 1 valence electron. For $HNO_2$, the total number of valence electrons is $1 + 5+2\times6=18$.

Step2: First resonance structure

The nitrogen atom is the central atom. One oxygen is bonded to nitrogen with a single - bond and also bonded to hydrogen. The other oxygen is double - bonded to nitrogen. The oxygen with a single - bond to nitrogen has 3 lone - pairs and a formal charge of - 1, the nitrogen has 1 lone - pair and a formal charge of + 1, and the oxygen with a double - bond has 2 lone - pairs and a formal charge of 0.

Step3: Second resonance structure

Switch the positions of the single - bonded and double - bonded oxygen atoms. The oxygen that is now single - bonded to nitrogen has 3 lone - pairs and a formal charge of - 1, the nitrogen has 1 lone - pair and a formal charge of + 1, and the oxygen that is now double - bonded to nitrogen has 2 lone - pairs and a formal charge of 0.

Answer:

The first resonance structure: $H - O - N=O$, where the oxygen bonded to hydrogen has 3 lone - pairs and a formal charge of - 1, nitrogen has 1 lone - pair and a formal charge of + 1, and the double - bonded oxygen has 2 lone - pairs and a formal charge of 0.
The second resonance structure: $H - O=N - O$, where the oxygen bonded to hydrogen has 3 lone - pairs and a formal charge of - 1, nitrogen has 1 lone - pair and a formal charge of + 1, and the single - bonded oxygen has 3 lone - pairs and a formal charge of - 1.