Introducing -ite and -ate ions

Elements may form more than one oxoanion. 
The ion with the maximum number of oxygens has an -ate ending.

The examples below show that for -ate ions that have no per- prefix on their name, the oxoanion with the -ite ending has
  • one fewer oxygen than the corresponding mononuclear ion ending in -ate.
  • the same charge as the corresponding mononuclear oxoanion ending in -ate.
nitrate NO3 sulfate SO42–
nitrite NO2 sulfite SO32–