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.
In organic chemistry, functional groups are specific groups of atoms or bonds within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of. However, its relative reactivity can be modified by other functional groups nearby. The atoms of functional groups are linked to each other and to the rest of the molecule by covalent bonds