Chemical Nomenclature SCH3u/4C Ms. Richardson 2016

Review – Binary Ionic Compounds Binary ionic compounds are composed of two elements metal + non-metal To name binary ionic compounds, we name the metal and then the non-metal, while changing the suffix of the non-metal to “-ide” Example: AgCl  silver chloride

Review – Binary Ionic Compounds To write the formula for binary ionic compounds, we use the criss-cross or swap n’ drop rules: Write the chemical formula of each element including the charge (be sure to write the metal first) Swap the charges so that they become subscripts Drop the sign of the charge If the two subscripts have a common factor, reduce the values: Mg2O2  MgO Al3 + O2- Al3 + O2- Al2- O3+ Al2O3

Review – Ionic Compounds with Multivalent Metals Many transition metals have more than one oxidation state (charge) and this must be indicated when we name the compound. We use roman numerals to identify the charge: iron (III) chloride  FeCl3 Iron (II) chloride  FeCl2

Review – Polyatomic Ions Polyatomic ions are a group of 2 or more elements that when bonded together, carry an overall charge. It is very important to remember that polyatomic ions act as a single unit and are never separated. Example: phosphate PO43- carbonate CO32- ammonium NH4+

Review – Polyatomic Ions Your periodic table contains a list of common polyatomic ions. It is important that can recognize them in chemical formula You can recognize the names as they typically end in “-ate” or “-ite” instead of the usual “-ide”. To name compounds containing polyatomic ions, simply name the cation first, and the anion last. You do not need to change the suffix of polyatomic ions.

Review – Polyatomic Ions To write the formula for compounds containing polyatomic ions, use the swap n’ drop rules. If a subscript is placed next to a polyatomic ion, you must place brackets around the entire polyatomic ion to separate it from the subscript Example: copper (II) hydroxide Cu(OH)2

Review – Binary Acids Acids contain hydrogen and a non-metal. To be considered an acid, they must be dissolved in solution as indicated by the “aqueous” (aq) state of matter. To name an acid, we identify the non-metal and add the prefix hydro- and the suffix –ic acid. Eg: HCl(aq) hydrochloric acid If the compound is not aqueous, use regular ionic naming rules Eg: HCl hydrogen chloride

Oxyacids Oxyacids are made of a hydrogen ion and a polyatomic ion. Oxyacids do not need to be dissolved in water, so do not need to be in the aqueous state.

Naming Oxyacids Identify the polyatomic ion in the acid and write its full name If the polyatomic ion ends in –ate, change the suffix to –ic acid If the polyatomic ion ends in –ite, change the suffix to –ous acid Example: H2SO4 sulfuric acid H2SO3 sulfurous acid

Peroxides Many ionic compounds are metal oxides – they contain a metal cation with the oxygen O2- ion. Peroxides are a slight variation in that they contain oxygen, but the peroxide ion is O22-, so they appear to contain an ‘extra’ oxygen To name peroxides, simply name the metal ion, and add “peroxide” to the end. Example: Na2O2 sodium peroxide H2O2 hydrogen peroxide

Hydrates Hydrates are ionic compounds that have “n” number of water molecules loosely bonded to them. Example: CuSO45H2O copper (II) sulfate pentahydrate

Number of Water Molecules Naming Hydrates Number of Water Molecules Prefix 1 mono- 2 di- 3 tri- 4 tetra- 5 penta- 6 hexa- 7 hepta- 8 octa- 9 nona- 10 deca- To name a hydrate, name the ionic compound first using regular naming rules. Identify the number of water molecules attached. Indicate the number of water molecules using the prefixes shown at right. End the name with “hydrate”