Given the following Lewis structure for butane: ${\mathrm{CH}}_3$-${\mathrm{CH}}_2$-${\mathrm{CH}}_2$-${\mathrm{CH}}_3$, which of the following best represents its skeletal structure?

• A. A straight line with two vertices, representing three carbon atoms
• B. A branched structure with three carbons in the main chain and one carbon attached to the middle carbon
• C. A triangle, representing a three-carbon ring
• D. A straight line with three vertices (zig-zag), representing four carbon atoms connected in a chain

Answer: (D)

Verified step by step guidance

1. Understand that the molecular formula for butane is C4H10, meaning it has four carbon atoms connected in a chain with hydrogens filling the remaining valences.
2. Recognize that the Lewis structure given is CH3-CH2-CH2-CH3, which shows a straight chain of four carbon atoms with appropriate hydrogens attached.
3. Recall that in skeletal structures, carbon atoms are represented by vertices (corners) or line ends, and hydrogens attached to carbons are usually omitted for simplicity.
4. Translate the four-carbon chain into a zig-zag line with three vertices, where each vertex corresponds to a carbon atom, and the ends represent the terminal carbons, thus showing all four carbons connected linearly.
5. Confirm that the correct skeletal structure for butane is a straight zig-zag line with three vertices, representing the four carbon atoms in a continuous chain without any branches or rings.