Step 1: Find valence e- for all atoms. Add them together.
Step2: Find octet e- for each atom and add them together.
Step3: Subtract step 1 total from step 2. Gives you bonding e-.
Step 4: Find number of bonds by diving the number in step 3 by 2(because each bond is made of 2 e-)
16e-/2= 8 bond pairs
Step 5: Find the number of nonbonding (lone pairs) e-. Subtract step 3 number from step 1.
20-16= 4e-=2 lone pairs
Use information from step 4 and 5 to draw the lewis structure.
Lewis dot structure of C2H5OH
Alternatively a dot method can be used to draw the lewis structure.
Calculate the total valence electrons in the molecule.
Total=20 i.e . 10 pairs