Final answer:
The Lewis structure for ethane (C₂H₆) comprises two carbon atoms, each bonded to three hydrogens and one another with single bonds, completing the octet for the carbon atoms and the duet rule for hydrogen atoms. There are no lone pairs of electrons in this structure.
Step-by-step explanation:
The student asked how to draw the Lewis structure for C₂H₆ (ethane), which has the skeletal structure H₃CCH₃. The first step to draw a Lewis structure is to calculate the total number of valence electrons for the molecule. For C₂H₆, this is calculated as (2 × 4) + (6 × 1) = 14.
Next, we draw a skeleton structure with the carbons in the center and the hydrogens connected to them, as hydrogen atoms can never be central atoms. Each pair of electrons shared between two atoms constitutes a single bond. Since each carbon shares three single bonds with hydrogen and one single bond with the other carbon, there are no lone pairs in this molecule. Therefore, each hydrogen is bonded to a carbon atom, and the two carbon atoms are bonded together, completing the octet for both carbon atoms and the duet for all hydrogen atoms. No double or triple bonds are needed since each atom already satisfies the octet/duet rule.
In a skeletal structure, carbon atoms are inferred at the ends and bends, and hydrogen atoms attached to carbon are not drawn. Since the Lewis structure should include all lone pairs and atoms, we do not use the skeletal structure for this exercise.