Ion Symbol & Name Rules

  1. Ions are charged particles that have a symbol or formula and a name.
  2. When an ion symbol is written you must include the charge of the ion.
  3. When an ion name is written you do not include the charge of the ion.

Cation (+) Ion Rules

    1. Elemental cation names look like the element names, so they must end in the word ion.
    2. Elemental cation charges are determined by their family on the Periodic Table.
    3. Ions that can hold more than one charge must have different names for each ion.
    4. There are two naming methods.

Classical Names: Suffix -ic means greater positive charge

          Suffix -ous means lesser positive charge

Stock Names: Roman Numerals indicate the positive charge

            Odd Ions That Do Not Follow Cation Rules As Stated:        NH41+

Anion (-) Ion Rules

    1. Elemental anion names end in the suffix -ide.
    2. Anion suffixes -ate & -ite mean that oxygen is present.

      Suffix -ate means the number of oxygens can be predicted by the Periodic Table.

      Suffix -ite means one less oxygen than -ate. Yet both hold the same charge.

    3. Oxygen always acts as the Oxide ion with a (-2) charge, so almost anything that attaches to oxide to form an ion must be positive in charge. (Two negative things repel.)
    4. Prefix bi- means that a Hydrogen Ion H1+ has attached to an anion and decreased its charge by one

Odd Ions That Do Not Follow Anion Rules As Stated:

CN 1- cyanide        OH 1- hydroxide        C2H3O2 1- acetate        MnO4 1- permanganate

ClO 1- hypochlorite hypo- prefix means under, so one oxygen under chlorite

ClO21- chlorite        ClO31- chlorate

ClO41- perchlorate per- (hyper-) prefix means above, so one oxygen above chlorate

H2PO41- hydrogen biphosphate or dihydrogen phosphate Di- prefix means two

Cr2O7 2- dichromate        C2O4 2- oxalate