Writing Ionic Formulas and Naming Ionic Compounds

Writing Formulas Steps 1. Write each element with it’s charge (Periodic Table Columns can help with this) 2. Switchy-Switchy Hint: Switchy-Switchy Example: Let’s make a compound using magnesium and chlorine MgCl +2 Example

Writing Formulas Steps 1. Write each element with it’s charge (Periodic Table Columns can help with this) 2. Switchy-Switchy 3. Reduce Hint: Switchy-Switchy Example: MgCl 2 MgCl 21 Example

Naming Ionic Compounds Example: MgCl 2 Steps 1. Name the metal (cation) 2. If the metal is a transition element, you must add a Roman Numeral in ( ) for the charge number (oxidation number) 3. Name the non-metal (anion) changing ending to –ide MagnesiumChloride

Let’s look at TiO TitaniumOxide Is titanium a transition element? Then we need a Roman Numeral But which one? We need to balance the charge The charge of O is _____, so we must be using a Ti with a charge of _____ (II) Remember Switchy-Switchy then reduce

Anion Endings If you see a name that ends in –ide, you are dealing with an element, unless peroixde, hydroxide, or cyanide If you see a name that ends in -ate or –ite, you are dealing with a polyatomic ion (Page 178 or back of periodic table)

How to read/name Polyatomic Ions The first “rule” looks at the number of oxygens in an ion Think of the -ate ion as being the "base" name The per- prefix adds an oxygen. -ite will reduce the oxygens by one. Adding hypo- to the –ite version will reduce the number of oxygens by another 1 In all situations, the charge is NOT affected.

For example, let’s look at the polyatomic ions that involve chlorine Cl - ClO - ClO 2 - ClO 3 - ClO 4 - chloride chlorate hypochlorite perchlorate chlorite

How to read/name Polyatomic Ions “Rule 2”: 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 An Example: Carbonate – CO 3 2- Bicarbonate – HCO 3 -

( ) How to work with polyatomic ions Think of them as a single ion All the atoms stay together and if you need more than one, you have to use parenthesis. For example, Magnesium Hydroxide MgOH 2 +2

Practice CationAnionNameFormula Lithium bromide Na 2 O PbF 2 Mg +2 PO 4 -3 Cu 2 CO 3 Ammonium sulfate NH 4 + SO 4 -2 F-F- Pb +2 Li + Na + Br - CO 3 -2 (NH 4 ) 2 SO 4 LiBr Lead (II) Fluoride Copper (I) Carbonate Magnesium phosphate Mg 3 (PO 4 ) 2 Cu + Sodium oxideO -2