<P> Functional groups, called hydrocarbyl, that contain only carbon and hydrogen, but vary in the number and order of double bonds . Each one differs in type (and scope) of reactivity . </P> <Table> <Tr> <Th> Chemical class </Th> <Th> Group </Th> <Th> Formula </Th> <Th> Structural Formulae </Th> <Th> Prefix </Th> <Th> Suffix </Th> <Th> Example </Th> </Tr> <Tr> <Td> Alkane </Td> <Td> Alkyl </Td> <Td> R (CH) H </Td> <Td> </Td> <Td> alkyl - </Td> <Td> - ane </Td> <Td> Ethane </Td> </Tr> <Tr> <Td> Alkene </Td> <Td> Alkenyl </Td> <Td> R C = CR </Td> <Td> </Td> <Td> alkenyl - </Td> <Td> - ene </Td> <Td> Ethylene (Ethene) </Td> </Tr> <Tr> <Td> Alkyne </Td> <Td> Alkynyl </Td> <Td> RC ≡ CR' </Td> <Td> R − C ≡ C − R ′ (\ displaystyle (\ ce (R-C #C-R'))) </Td> <Td> alkynyl - </Td> <Td> - yne </Td> <Td> H − C ≡ C − H (\ displaystyle (\ ce (H-C #C-H))) Acetylene (Ethyne) </Td> </Tr> <Tr> <Td> Benzene derivative </Td> <Td> Phenyl </Td> <Td> RC H RPh </Td> <Td> </Td> <Td> phenyl - </Td> <Td> - benzene </Td> <Td> Cumene (Isopropylbenzene) </Td> </Tr> </Table> <Tr> <Th> Chemical class </Th> <Th> Group </Th> <Th> Formula </Th> <Th> Structural Formulae </Th> <Th> Prefix </Th> <Th> Suffix </Th> <Th> Example </Th> </Tr> <Tr> <Td> Alkane </Td> <Td> Alkyl </Td> <Td> R (CH) H </Td> <Td> </Td> <Td> alkyl - </Td> <Td> - ane </Td> <Td> Ethane </Td> </Tr>

What are 2 atoms that all organic compounds have in common