Naming Ionic Compounds

Naming Ionic Compounds

Naming Rules

• Cations (metals) are named before anions (non-metals).

• For transition metals, indicate valency using numerals (e.g., Fe(III)).

• Metal cation names remain unchanged (e.g., Sodium ion, Na^+ ion).

• Non-metal anion names change to end with '-ide'.

Common Ions

• Cations: Examples include Caesium (Cs^+), Copper(I) (Cu^+), Barium (Ba^{2+}), Aluminium (Al^{3+})

• Anions: Examples include Bromide (Br^-), Oxide (O^{2-}), Nitride (N^{3-}).

Chemical Formulas

• Write the positively charged ion (cation) symbol first.

• Use subscripts to indicate the number of each ion.

• Omit the subscript '1'.

• Do not include charges in the final formula.

Steps for Writing Formulas

1. Write the symbol and charge of each ion.

2. Find the lowest common multiple (LCM) of the charges.

3. Determine the number of cations and anions needed to equal the LCM.

4. Write the formula with the cation first, using subscripts to indicate the number of each ion.

Examples

• Lithium Oxide: Li_2O

• Aluminum Oxide: Al2O3

• Calcium Chloride: CaCl_2