Chemical Nomenclature

Positive Ions  (Cations):

a) Cations formed from metal atoms have the same name as the metal, e.g. Na+ is the sodium ion
b) If a metal can form different cations, the positive charge is indicated by a Roman numeral in parentheses following the name of the metal, e.g. Au+ is the gold(I) ion and Au3+ is the gold(III) ion.
c) Cations formed from nonmetal atoms have names that end in -ium, e.g. NH4+ is the ammonium ion.

Some examples of cations that you might encounter:

Negative Ions  (Anions):

a) The names of the monatomic anions are formed by replacing the ending of the name of the element with -ide, e.g. O2- is the oxide ion.
b) Polyatomic anions containing oxygen (called oxyanions) have names ending in -ate or -ite, e.g. SO42- is the sulfate ion and SO32- is the sulfite ion.
c) Anions derived by adding H+ to an oxyanion are named by adding the prefix hydrogen or dihydrogen, e.g. HCO3- is the hydrogen carbonate ion

More on naming oxyanions:

Some examples of anions that you might encounter:

Chemical Nomenclature Ionic Compounds:

Names of ionic compounds consist of the name of the cation followed by the name of the anion, e.g. Cu(ClO4)2 is copper(II) perchlorate, and CaCO3 is calcium carbonate.

Chemical Nomenclature Name and Formulae of Acids:

1. Acids containing anions whose names end in -ide are named by changing the -ide ending to -ic, adding the prefix hydro- to this anion name, and then following with the word acid (e.g. chloride becomes hydrochloric acid)
2. Acids containing anions whose names end in -ate or -ite are named by changing the -ate ending to -ic and the -ite ending to -ous and then adding the word acid. (e.g. sulfate becomes sulfuric acid, sulfite becomes sulfurous acid)

Some acids you need to know:
Sulfuric acid H2SO4
Sulfurous acid H2SO3
Phosphoric acid H3PO4
Carbonic acid H2CO3
Nitric acid HNO3
Acetic acid CH3COOH
Perchloric acid HClO4

An important base that is not simply a hydroxide salt that you need to know is ammonia NH3.

Chemical Nomenclature: Binary Molecular Compounds

1. The name of the element farther to the left in the periodic table is written first (e.g. H2O not OH2)
2. If both elements are in the same group in the periodic table, the one having the higher atomic number is written first ( e.g. SO2 not OS2)
3. The name of the second element is given an -ide ending (e.g. H2S is hydrogen sulfide)
4. Greek prefixes are used to indicate the number of atoms of each element.
Examples: N2O4 is dinitrogen tetroxide and P4S10 is tetraphosphorus decasulfide
Know the Greek prefixes up to 10: mono, di, tri, terta, penta, hexa, hepta, octa, nona, deca