CHEMICAL NOMENCLATURE

Chemical Nomenclature

System of names used to distinguish compounds from each other and the rules needed to devise these names

Ionic vs Molecular compounds Separate system for each, so the first

step is to identify whether the compounds are ionic or molecular

Here are two general rules: Ionic= metal + non-metal Molecular=non-metal + metal

Binary ionic compounds

Binary=two A binary compound is a compound in

which only two elements are present A binary ionic compound is an ionic

compound in which one element present is a metal and the other is a non-metal, such as NaCl

Rules for naming binary ionic compounds First word=name of metal Second word=stem name of nonmetal +

ide Let’s try a few:

NaCl Sodium chloride

MgF2

Magnesium flouride Na2O

Sodium oxide

Binary molecular compounds A molecular compound in which only two

non-metallic elements are present Rule:

First word: numerical prefix + full name of nonmetal

Second word: numerical prefix + stem name of second nonmetal + ide

Binary molecular compounds Common numerical prefixes:

Mono=1 Di=2 Tri=3 Tetra=4 Penta=5 Hexa=6

Binary Molecular Compounds Let’s try a few:

N205

Dinitrogenpentoxide PF3

Phosphorous trifluoride SiCl4

Silicon tetrachloride

Binary Molecular Compounds that have Common Names Common name: not based on IUPAC* rules

and has no information about composition of compound H2O=water H2O2=hydrogen peroxide NH3=ammonia CH4=methane

*IUPAC=International Union of Pure and Applied Chemistry