Carbon atoms can form the carbon chain

Carbon atoms can attach to each other to form the linier, branched, and circular or cyclic (form the rings) carbon chains. The linier or branched carbon chains may be thousands of carbons atom long, while the circular (cyclic) carbon chains usually contain from three to six carbon atoms. The chemical bond for carbon chains may be in forms, of single covalent bond, double covalent bond, or triple covalent bond.
Carbon atoms can be distinguished into primary carbon atom, secondary carbon atom, tertiary carbon atom and quarterly carbon atom.
The primary carbon atom is carbon atom attached by one the other C atom, the secondary carbon atom is carbon attached by two other C atoms, the tertiary carbon atom is carbon atom attached by three other C atoms, and the quarterly carbon atom is carbon atom attached by four other C atoms.
For example :
where :
1 = primary carbon atom
2 = secondary carbon atom
3 = tertiary carbon atom
4 = quarterly carbon atom