1. Also called: first cousin, cousin-german or full cousin the child of one's aunt or uncle. 2. a relative who has descended from one of one's common ancestors. A person's second cousin is the child of one of his parents' first cousins. A person's third cousin is the child of one of his parents' second cousins. A first cousin once removed (or loosely second cousin) is the child of one's first cousin.
As a functional group, benzene and substituted benzenes are called arenes. Nomenclature: Functional group suffix = -benzene (review) Functional group prefix = phenyl-Substituted benzenes are usually named as such.The relative positions can be denoted as 1,2- = ortho-, 1,3- = meta-and 1,4- = para-substitution.When polysubstituted, the numbers alone are used, e.g. 1,2,3-trimethylbenzene.omenclature: Functional group suffix = -benzene (review) Functional group prefix = phenyl-Substituted benzenes are usually named as such. The relative positions can be denoted as 1,2- = ortho-, 1,3- = meta-and 1,4- = para-substitution. When polysubstituted, the numbers alone are used, e.g. 1,2,3-trimethylbenzene.
Functional groups are groups of atoms in hydrocarbons which are responsible for their chemical properties. The types of functional groups include halocarbons, alcohols, ethers, aminoss, aldehydes, ketones, carboxyllic acids and esters. These functional groups are bound to a hydrocarbon structure denoted R.