Modern chemical nomenclature started with Berzeluis, one of the so-called fathers of chemistry, back in the early 1800s. He said that chemicals should be named by what they are, not by where they came from. (After all, you can find malic acid elsewhere, like in cherries.) He created the system of 1-letter and 2-letter atomic symbols taught today in secondary school, with the letters taken from the Latin words for the element (hence "Pb" for plumbum; lead).
He proposed that compounds be described by chemical formulas based on their elemental composition.
There are two "rules" that can be used for learning the nomenclature of polyatomic ions.
First, when the prefix bi- is added to a name, a hydrogen is added to the ion's formula and its charge is increased by 1, the latter being a consequence of the hydrogen ion carrying a +1 charge. An alternate to the bi- prefix is to use the word hydrogen in its place: the anion derived from H+ + CO32−, HCO3− can be called either bicarbonate or hydrogen carbonate.
Note that many of the common polyatomic anions are conjugate bases of acids derived from the oxides of non-metallic elements. For example the sulfate anion, SO42−, is derived from H2SO4 which can be regarded as SO3 + H2O.
The second rule looks at the number of oxygens in an ion.
First, think of the -ate ion as being the "base" name, in which case the addition of a per- prefix adds an oxygen. Changing the -ate suffix to -ite will reduce the oxygens by one, and keeping the suffix -ite and adding the prefix hypo- reduces the number of oxygens by two. In all situations, the charge is not affected. The naming pattern follows within many different oxyanion series based on a standard root for that particular series. The -ite has one less oxygen than the -ate, but different -ate anions might have different numbers of oxygen atoms.
These rules will not work with all polyatomic ions, but they do work with the most common ones (sulfate, phosphate, nitrate, chlorate).
Ite at the end of an ion means that the compound has 2 oxygen and -ate means there is 3 oxygen.
http://en.wikipedia.org/wiki/Polyatomic_ion
