Chains, branches and rings
Three shapes, each saturated or unsaturated.
Shapes of carbon skeletons
We have seen carbon atoms linked in a straight line and in a branched pattern. There is a third way to arrange carbon atoms.
What do you think the third arrangement is?
What this lesson covers
The idea
Carbon compounds may have straight chains, branched chains or carbon atoms arranged in a ring (cyclic), and each of these may be saturated or unsaturated.
Shapes of carbon skeletons
We have seen carbon atoms linked in a straight line and in a branched pattern. There is a third way to arrange carbon atoms.
What do you think the third arrangement is?
- A ring
- A straight chain with one more atom
- A branched chain with one more branch
Three shapes
Open every tab.
Shape and bonds are separate
The shape of the carbon skeleton and the kind of bonds between the carbons are two different things. Any shape can have single bonds only or a double or triple bond.
Carbon compounds may have straight chains, branched chains or carbon atoms arranged in a ring (cyclic), and each of these may be saturated or unsaturated.
Notes
Carbon compounds may have straight chains, branched chains or carbon atoms arranged in a ring (cyclic), and each of these may be saturated or unsaturated.
Check yourself
What do we call carbon compounds in which the carbon atoms are arranged in a ring?
How many hydrogen atoms are there in a molecule of cyclohexane, C₆H₁₂?
Answer: 12
The formula C₆H₁₂ has 12 hydrogen atoms.
Benzene, C₆H₆, is a ring with double bonds. What kind of compound is it?
Which statement is correct?
- Branched compounds. A branched compound has a chain with a side branch, not a ring.
- Straight chain compounds. A straight chain compound has its carbon atoms in a line, not in a ring.
- Cyclic compounds — correct. Yes!
- Unsaturated — correct. Yes!
- Saturated. A saturated compound has only single bonds between carbon atoms. Benzene has double bonds.
- A straight chain compound. Benzene has its carbon atoms in a ring, not in a straight chain.
- A ring-shaped compound is always saturated. Benzene has a ring and is unsaturated, so a ring may be saturated or unsaturated.
- A ring-shaped compound may be saturated or unsaturated — correct. Yes!
- Only chains can be unsaturated. Rings can be unsaturated too. Benzene, C₆H₆, is an example.