SNC 1D1 –Nomenclature Review Chemical Nomenclature:

1. SNC 1D1 –Nomenclature Review Chemical Nomenclature: Chemical nomenclature is decided by IUPAC (international union of pure and applied chemistry.) This organization establishes rules and guidelines for naming organic and inorganic compounds. It is an easy-to-use system that identifies the composition of every compound. It is a chemical language.

2. Binary Compounds: • In ionic bonds the simplest compounds are called binary compounds. • These are made up of 2 types of monoatomic ions (an ion made up of only 1 charged atom.) • The metal is stated in full, the non-metal ion has the ide suffix added. • NaCl – sodium chloride • LiBr – lithium bromide • Binary compounds can be made up of more than two ions as long as there are only 2 kinds of atoms Ex. aluminum oxide – Al2O3.

3. Valence: • The charge on the ion is sometimes called the valence. • The charge on an atom is sometimes also called the oxidation number. • This is not to be confused with valence electrons which are the electrons found in the outermost orbital of an atom.

4. Writing the Formulas of Ionic Compounds: • Write the symbols in the order they should appear in the compound (metals first, non-metals second). • For magnesium chloride: Mg Cl • Write the valences (ionic charges) above the symbols. Mg Cl • Using the criss-cross rule, make the valences subscripts: Mg Cl • MgCl2 (note the subscript 1 for Mg is assumed and signs are omitted) +2 -1 +2 -1

5. Multivalent Metals: (table 2 pg. 92) • Some metals (usually the transition metals) have more than one valence or charge. Ex Fe 2+ or Fe 3+. • Your periodic table shows the most common ion of each element. • An element like iron can form either FeCl2 or FeCl3 depending on the valence of iron. • Roman numerals are used to express the charge on the ion. • Ex. iron (II) chloride = FeCl2 iron (III) chloride = FeCl3

6. Polyatomic Ions: • Compounds with more than 2 atoms are called tertiary compounds. • Usually compounds of a metal ion and a polyatomic ion. • Polyatomic ions are a group of ions that bond together with a net charge. • When writing chemical formulas the polyatomic ion is treated like a regular ion. Ex. calcium nitrate Ca 2+ NO31- → Ca(NO3)2 • Brackets are placed around polyatomic ions when there are 2 or more ions in the compound.

7. Hydrates: • Some tertiary compounds (metal + polyatomic ion) contain molecules of water within their crystal structures, these compounds are called hydrates. • When hydrates are heated this water is released from the compound. • This is called water of hydration. • When this water is removed the product is called anhydrous. CuSO4 • 5H2O – copper (II) sulfate pentahydrate CuSO4 - anhydrous copper (II) sulfate • The prefixes for hydrates in compounds are given in table 4 pg. 96.

9. Oxyacids • Compounds made by combining hydrogen with an oxyanion are called oxyacids. These compounds can be named according to 2 naming systems: IUPAC • H2SO5(aq) - aqueous hydrogen persulfate • H2SO4(aq) - aqueous hydrogen sulfate • H2SO3(aq) - aqueous hydrogen sulfite • H2SO2(aq) - aqueous hydrogen hyposulfite • This naming system applies for all other oxyacids (acids made from NO3-1, CO3-2, ClO3-1, PO4-3 etc.)

10. Classical Naming System • According to the classical naming system the suffixes of the acids change depending on the number of oxygen atoms in the polyatomic ion.