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.
A functional group is a portion of a molecule that is a recognizable/classified group of bound. atoms. In organic chemistry it is very common to see molecules comprised mainly of a carbon. backbone with functional groups attached to the chain. The functional group gives the molecule. its properties, regardless of what molecule contains it*; they are centers of chemical reactivity. The functional groups within a molecule need to be identified when naming. *Definition taken from Lecture Supplement, First Edition by Steven Hardinger, Copyright 2008.