How to get the hybridization of N IN NO2- ?
I do it as an after the fact method.
Draw the Lewis dot structure.
1 N = 1 x 5 electrons = 5 e
2 O = 2 x 6 e = 12 e
1 e for charge = 1 e
total electrons = 18.
 O
  |
:N=O
Now place 3 pairs e (6 electrons total) around top O and 2 pairs around side O. That should use up the 18.
Count the regions of high electron density. There are 3 (1 for double bond, 1 for single bond, and 1 for unpaired set electrons on N. Three regions of high electron density = trigonal planar arangement and sp2 hybridization.
To determine the hybridization of nitrogen (N) in NO2-, you need to follow a few steps:
Step 1: Draw the Lewis structure of NO2-
Start by drawing the Lewis structure of NO2-. Nitrogen (N) will be the central atom, surrounded by two oxygen (O) atoms. The structure will look like a bent molecule with two lone pairs of electrons on the nitrogen atom.
Step 2: Count the number of regions of electron density around the nitrogen atom
Next, count the number of regions of electron density around the nitrogen atom. This includes bonded atoms and lone pairs of electrons. In NO2-, nitrogen is bonded to two oxygen atoms and has one lone pair of electrons. So, the total number of regions of electron density is three.
Step 3: Determine the hybridization
The hybridization of an atom depends on the number of regions of electron density. In the case of three regions of electron density, the hybridization is sp2.
Therefore, the nitrogen atom in NO2- is sp2 hybridized.
Note: The concept of hybridization helps to explain the molecular geometry and the bonding of atoms in a molecule. The hybridization of nitrogen in NO2- is sp2, which leads to the bent shape of the molecule.