To draw the Lewis structure for H3C-CH3 (ethane), we start by determining the number of valence electrons available. Carbon (C) has four valence electrons and hydrogen (H) has one. Since there are two carbon atoms and six hydrogen atoms, the total number of valence electrons is:
2 (C) × 4 + 6 (H) × 1 = 8 + 6 = 14 valence electrons.
Next, we arrange the atoms. Ethane has a straight-chain structure with two carbon atoms bonded to each other, with each carbon atom further bonded to three hydrogen atoms:
- 1st Carbon (C) bonded to 3 Hydrogen (H) atoms
- 2nd Carbon (C) bonded to the 1st Carbon and to 3 Hydrogen (H) atoms
This creates single bonds (represented by a line) between the C and H atoms. Here’s how the Lewis structure looks:
H3C – C H3
In the sketch, each dash represents a pair of shared electrons or a covalent bond. Each hydrogen has its single bond with carbon, fulfilling the hydrogen atoms’ duet rule. Each carbon atom reaches an octet by forming four total bonds (three with H and one with the other C).
For a 3D representation, it’s important to visualize the molecule’s tetrahedral geometry. The bond angles are approximately 109.5°, thus giving a three-dimensional shape. In this configuration, the hydrogens are oriented away from each other in space. You can represent this structure using 3D models or software that can illustrate molecular geometries.
In conclusion, sketching Lewis structures and visualizing molecular shapes are fundamental for understanding molecular interactions and behaviors in chemistry.