Draw and Explain the Lewis Structure for C2H2O

To draw the Lewis structure for C₂H₂O (ethylene glycol) step by step, follow these instructions:

1. Count the Total Valence Electrons: The molecule has two carbon (C) atoms, two hydrogen (H) atoms, and one oxygen (O) atom.
• Carbon: 4 electrons × 2 = 8
• Hydrogen: 1 electron × 2 = 2
• Oxygen: 6 electrons = 6

Total = 8 + 2 + 6 = 16 valence electrons.

2. Determine the Central Atom: Carbon is less electronegative than oxygen, so we will place the oxygen in the center.
3. Connect the Atoms: Connect the two carbon atoms to the oxygen atom. This will look like:

C - O - C

4. Add Single Bonds: Each single bond uses 2 electrons. Connecting these three atoms uses up 6 electrons:

C - O - C

(6 electrons used)

5. Place Remaining Electrons: You now have 10 electrons left (16 total – 6 used). Distribute the remaining electrons to fulfill the octet rule.
6. Form Double Bonds: To satisfy the octet rule for the carbon atoms, you need to form double bonds. Replace two of the lone pairs on oxygen to form double bonds with each carbon:

C = O = C

7. Final Structure: The final Lewis structure looks like this:

H - C = O = C - H

Each carbon is bonded to one hydrogen and has a double bond with the oxygen. The oxygen has two lone pairs of electrons.

This structure shows that all atoms achieve their desired electron configurations: each carbon has 4 bonds (2 from the double bond and 1 from the hydrogen), and the oxygen has 8 electrons (4 from the double bonds and 4 in lone pairs).