Question

Determine the resonance structures, the steric number, and geometry of$N{o}_2$ion. Also, determine the bond order ofN-O-.

Short answer

Bonding between atoms in covalent molecules is shown by diagrams known as Lewis structures. These also show lone pairs in a molecule.

The hybridization of N atom is determined by a steric number.

Step-by-step solution

The formula to calculate the steric number of

The formula to calculate the steric number of N atom is as follows:

The number of lone pairs on N atom is 1.

The number of atoms bonded to N atom is 2.

Substitute these values in the above formula

N atom in${\mathrm{NO}}_2^{-}$has steric number 3. Therefore, it hashybridization, with one lone pair. Also,hybridization with one lone pair has bent or angular geometry.

The electronic configuration ofis$2s^{2}2p^3$.

The electronic configuration of is$2s^{2}2p^4$ .

Calculate the total number of valence electrons

The formula to calculate total number of valence electrons inis as follows:

Total number of electrons

Valence electron ofis 5.

Valence electron ofis 6.

Formal charge is -1.

Substitute these values in the above formula

Total number of electrons = Valence electrons of valence electrons of N+2(Valance electrons of O )

+formal charge

${\mathrm{NO}}_2$-has 18 valence electrons. Two electrons are placed in each oxygen 2 s orbital and 2 in each nonbonding 2 p orbital of oxygen. Therefore, a total of 8 electrons are localized on oxygen atoms. Also, two electrons are placed as lone pairs in third$s{p}^2$orbital of nitrogen atom. Out of 8 remaining electrons, 4 electrons are involved in two$\sigma$bonds between nitrogen and the oxygen atoms. The last 4 electrons are placed into the$\pi$electron system: 2 into the bondinglocalid="1664190806521" $\pi$orbital and 2 into the nonbondinglocalid="1664190735329" $\pi$orbital. The electrons in bondingmolecular orbital is delocalized over the three atoms in the molecule.

The 2 p orbital is perpendicular to the plane of molecule combined into $\pi$molecular orbital that contains one pair of electrons.

The bond order of the molecule is 1.5 to each localid="1664190782530" $\mathrm{N}-\mathrm{O}$bond aslocalid="1664190793598" ${\mathrm{NO}}_2^{-}$is a hybrid of two resonating structures and three electrons of nitrogen are involved. Therefore, the bond order is as follows:

The molecular orbital diagram of NO2-