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 collections of atoms in organic chemistry molecules that contribute to the chemical characteristics of the molecule and participate in predictable reactions.These groups of atoms contain oxygen or nitrogen or sometimes sulfur attached to a hydrocarbon skeleton.Organic chemists can tell a lot about a molecule by the functional groups that make up a molecule.hese groups of atoms contain oxygen or nitrogen or sometimes sulfur attached to a hydrocarbon skeleton. Organic chemists can tell a lot about a molecule by the functional groups that make up a molecule.