Draw the Lewis structure of `NO_(2)^(-)` (Nitrite ion) .

Explanation

Step 1 : N = 2, 5, O = 2, 6, -ve charge = 1 `" " therefore` Total no. of valence electrons in `NO_(2)^(-)=5+2xx6+1=18=9` pairs.
Step 2 : Skeletal structure of `NO_(2)^(-)` will be O N O
Step 3: Putting a single bond (one shared pair) between O and N and N and O, we have `[O:N:O]^(-)`
Step 4: Putting the remaining 7 pairs of electrons as lone pairs, 3 on each O and 1 on N (so that octets of O are completed), we have `[:underset(* *)overset(* *)O:overset(* *)N:underset(* *)overset(* *)O:]^(-)`
Step 5: As octet of N is not complete, multiple bonding is required. As N is short of only one pair of electrons, one pair from O should be shifted as shared pair between O and N or N and O, i.e., a double bond should exist. Thus, the structure should be
`[underset(* *)overset(* *)O::N:underset(* *)overset(* *)O:]^(-) or [: underset(* *)overset(* *)O: N::underset(* *)overset(* *)O:]^(-)i.e., [underset(* *)overset(* *)O=N-underset(* *)overset(* *)O:]^(-)or [:underset(* *)overset(* *)O-N=underset(* *)overset(* *)O]^(-)`