What will be the formula and electron dot structure of cyclopentane?
Formula: The molecular formula of cyclopentane is C₅H₁₀.
Electron Dot Structure: Cyclopentane is a saturated hydrocarbon (alkane) where five carbon atoms are linked in a cyclic ring structure. In the electron dot structure, each carbon atom forms single bonds with two adjacent carbon atoms to form a pentagon. Each carbon atom also bonds with two hydrogen atoms to satisfy its valency of four. All valencies are satisfied by single bonds, making it a saturated compound. The structure shows five C atoms in a ring, with each C atom having two H atoms attached, and all bonds represented by pairs of dots (electrons).
Explanation
The textbook context shows that pentane (straight chain) has the formula C₅H₁₂. When carbon atoms form a cyclic structure (as shown for cyclohexane in Figure 4.9), two hydrogen atoms are removed because the chain ends join together. Since cyclohexane is C₆H₁₂, cyclopentane follows the same pattern with C₅H₁₀. The context explains that saturated hydrocarbons (alkanes) have all valencies satisfied by single bonds between atoms, as demonstrated in the electron dot structure of ethane. Cyclopentane, being a cyclic alkane, has all single bonds between carbon atoms in a ring formation.
Solution Steps
Step 1: Identify that cyclopentane is a cyclic saturated hydrocarbon (alkane) with 5 carbon atoms.
Step 2: Apply the general formula for cycloalkanes: CₙH₂ₙ, giving C₅H₁₀.
Step 3: Draw 5 carbon atoms in a ring with single bonds between them.
Step 4: Attach 2 hydrogen atoms to each carbon atom to satisfy the valency of 4 for each carbon.