Given alkane:
H3C − CH2 − C(CH3)2 − CH2 − CH(CH3)2
Concept:
• Primary (1°) carbon: Carbon attached to only one other carbon
• Secondary (2°) carbon: Carbon attached to two other carbon atoms
• Terciary (3°) carbon: Carbon attached to three other carbon atoms
Identification of carbon atoms:
1° (Primary) carbon atoms:
All CH3 groups are primary carbons.
Number of 1° carbon atoms = 5
Each 1° carbon is bonded to 3 hydrogen atoms.
2° (Secondary) carbon atoms:
The CH2 groups are secondary carbons.
Number of 2° carbon atoms = 2
Each 2° carbon is bonded to 2 hydrogen atoms.
3° (Tertiary) carbon atoms:
The carbon atoms written as C(CH3)2 and CH(CH3)2 are tertiary carbons.
Number of 3° carbon atoms = 2
Each 3° carbon is bonded to 1 hydrogen atom.
Final Summary:
| Type of carbon | Number of carbons | Hydrogen atoms bonded to each |
|---|---|---|
| 1° (Primary) | 5 | 3 |
| 2° (Secondary) | 2 | 2 |
| 3° (Tertiary) | 2 | 1 |