Butane (C₄H₁₀) electron dot structure:
$$\text{H : C : C : C : C : H}$$
H H H H H H H H
(Each carbon shares single bonds with adjacent carbons and hydrogen atoms, with all valencies satisfied.)
Source: Chapter 4, Section 4.2.2
---
Butane has 4 carbon atoms in a straight chain, each forming 4 covalent bonds. The two end carbons bond to 3 H atoms each, and the two middle carbons bond to 2 H atoms each, giving C₄H₁₀. In the electron dot structure, show each shared pair as two dots (or a line) between atoms. Examiners want all bonds shown correctly with valencies satisfied — this is the key scoring point for 1 mark.