Write the Lewis structure for ethanol (CH3CH2OH), the alcohol found in alcoholic beverages, then answer the following questions

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Write the Lewis structure for ethanol (CH3CH2OH), the alcohol found in alcoholic beverages, then answer the following questions: 1. How many valence electrons does this alcohol have? 2. How many bonded electrons does this alcohol have? 3. How many lone pairs of electrons does this alcohol have? 4. How many single bonds does this alcohol have?

The correct Answer and Explanation is:

Lewis Structure for Ethanol (CH₃CH₂OH)

The Lewis structure of ethanol (CH₃CH₂OH) can be drawn by representing each atom with its valence electrons and forming bonds between atoms to satisfy the octet rule for each element (except hydrogen, which follows the duet rule).

  • Carbon (C) has 4 valence electrons.
  • Hydrogen (H) has 1 valence electron.
  • Oxygen (O) has 6 valence electrons.

To draw the structure:

  1. The first carbon (CH₃) is attached to three hydrogens.
  2. The second carbon (CH₂) is attached to two hydrogens and one oxygen.
  3. The oxygen (OH) is attached to the second carbon and a hydrogen atom.

Step-by-Step Lewis Structure:

  • The first carbon (C1) forms three single bonds with three hydrogen atoms (H₁, H₂, H₃), leaving one valence electron for bonding.
  • The second carbon (C2) bonds to two hydrogen atoms (H₄, H₅), one bond to C1, and one bond to oxygen.
  • Oxygen bonds to C2 and one hydrogen atom (H₆), completing the structure.

The structure looks like this:

H H H
| | |
H - C - C - O - H
    | 
    H

Questions:

  1. How many valence electrons does ethanol have?
  • Ethanol contains 20 valence electrons. This comes from 6 hydrogen atoms (6 × 1 = 6), 2 carbon atoms (2 × 4 = 8), and 1 oxygen atom (1 × 6 = 6), totaling 6 + 8 + 6 = 20 valence electrons.
  1. How many bonded electrons does ethanol have?
  • Ethanol has 18 bonded electrons, which form 9 single bonds (each bond consists of 2 electrons).
  1. How many lone pairs of electrons does ethanol have?
  • Ethanol has 2 lone pairs of electrons. Both lone pairs are found on the oxygen atom because oxygen has 6 valence electrons, and after forming 2 bonds, 4 electrons remain as lone pairs.
  1. How many single bonds does ethanol have?
  • Ethanol contains 9 single bonds: 5 C–H bonds, 1 C–C bond, 1 C–O bond, and 1 O–H bond.

Explanation:

Ethanol’s structure reflects a typical organic alcohol, consisting of a hydrocarbon chain (CH₃CH₂) attached to a hydroxyl group (OH). The carbon atoms form a simple chain with hydrogen atoms, and the oxygen atom completes the hydroxyl group. Ethanol has 20 valence electrons total, with most electrons involved in bonds, while oxygen retains two lone pairs. This configuration provides stability to the molecule, as the carbon atoms satisfy the octet rule, and the oxygen atom’s lone pairs contribute to its chemical properties, such as hydrogen bonding.

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