Step 1: Find valence e- for all atoms. Add them together. N-5 H-1x3=3 Total=8 Step2: Find octet e- for each atom and add them together.
N-8 H-2x3=6 Total=14
Step3: Gives you bonding e-. Subtract step 1 total from step 2 14-8=6e-
Step 4: Find number of bonds by diving the number in step 3 by 2(because each bond is made of 2 e-) 6e-/2= 3 bond pairs
Step 5: Find the number of nonbonding (lone pairs) e-. Subtract step 3 number from step 1. 8-6= 2e-=1 lone pair
Use information from step 4 and 5 to draw the lewis structure. Nitrogen goes in the centre.
Lewis dot structure of ammonia
Alternatively a dot method can be used to draw the lewis structure of NH3.
Calculate the total valence electrons in NH3 molecule.
Put Nitrogen in the center and three hydrogen atoms on the sides.
Put a pair of electrons connecting the side atom with central atom.Put the fourth pair on the central atom,Nitrogen.