Naming Chemical Compounds

Beating The System  The system of naming that is used world- wide today is called the IUPAC system.  IUPAC is an acronym for International Union of Pure and Applied Chemistry.  The names and formulas used by IUPAC are universal throughout the world – much like the scientific names used in biology – you Homo sapiens!  This system helps to eliminate language barriers and problems of communication.

Names for Binary Ionic Compounds  A binary ionic compound is an ionic compound that is made of just two elements.  The elements involved with binary ionic compounds have formed ions – one positive and one negative.  These compounds have a first and last name just like you. The positive ion is always placed first in the formula and is written as the first name. The negative ion is second in both instances.  The general form of the name of a binary ionic compound is… Metal nonmetide  Notice that the first name stays the same as on the periodic table while the second name gets shortened and ends in “ide”.  Examples:  K 2 SNaClMg 2 N 3  Potassium sulfideSodium chlorideMagnesium nitride

Ionic Compounds with Transition Metals  There are several metals on the periodic table that are “shifty”. They are capable of having more than one ionic charge. Of course, being metals, this charge is positive.  These metals are:  Copper – Cu – I & II  Iron – Fe – II & III  Lead – Pb – II & IV  Tin – Sn – II & IV  When naming a compound, these metals must be identified not only with their name but with their charge.  The formulas of compounds that include these “shifty” metals do not have any Roman numerals in them.

Naming Ionic Compounds with Transition Metals  These, too, have a first and last name.  The first name is the name of the metal. This name is followed by a Roman numeral in brackets – just to show what form of the “shifty” metal it is.  The second name is the name of the nonmetal – shortened with the “IDE” ending.  Example:  Cu 3 NSnO 2  Copper (I) nitrideTin (IV) oxide

Polyatomic Ionic Compounds  A polyatomic ion is a cluster of atoms that travel together as a single unit that carries an overall charge.  Many of the polyatomic ions are negatively charged so when they are in an ionic compound they replace the nonmetal.  The polyatomic ions you need to know are:  Name (formula) charge  Hydroxide (OH) 1-  Nitrate (NO 3 ) 1-  Chlorate (ClO 3 ) 1-  Bicarbonate (HCO 3 ) 1-  Carbonate (CO 3 ) 2-  Sulfate (SO 4 ) 2-  Phosphate (PO 4 ) 3-  Ammonium (NH 4 ) 1+

Naming Polyatomic Ionic Compounds  Polyatomic compounds also get two names just like we do.  The first name will be the name of the positive ion – usually a metal – no changes are made to this first name.  The second name will be the name of the polyatomic ion as it is – there are no changes made to the name of polyatomic ions when they are used in a compound.  The second name – if the second part of the compound is just a nonmetal (not a polyatomic) – will be the shortened name of the nonmetal with the “IDE” ending.  Examples:  CaSO 4 K 3 PO 4 NH 4 Cl  Calcium sulfatePotassium phosphate Ammonium chloride

Hydrated Salts  A hydrated salt is an ionic compound that contains molecules of water within its structure.  These compounds are named by using the name of the ionic compound (the salt) followed by the term “hydrate” – which means water.  To indicate the amount of water being held within the structure, we use a prefix in front of the “hydrate” part of the name.  These prefixes are: Mono – 1 Tri – 3 Penta – 5 Hepta – 7 Nona – 9 Di – 2Tetra – 4Hexa – 6 Octa – 8 Deca – 10  Examples:  CuSO 4 ·5H 2 OMgSO 4 ·7H 2 O  Copper (II) sulfate pentahydrateMagnesium sulfate heptahydrate

Binary Covalent Compounds  Binary covalent compounds are those which are made of two nonmetals bonded together because they are sharing electrons. (Two bullies are sharing the toys!)  Covalent compounds do not form ions so you can’t go “positive ion first & negative ion second”. This means you have to name them differently than the ionic compounds.

Naming Binary Covalent Compounds  The covalent compounds use only nonmetals. They still have two names just like us.  Prefixes are used to show how much of each nonmetal is used to make the compound.  The prefixes used are: Mono – 1 Tri – 3 Penta – 5 Hepta – 7Nona - 9 Di – 2 Tetra – 4 Hexa – 6 Octa – 8Deca – 10  The first name is the name of the first nonmetal used. It will have a prefix only if there is more than one of it used. No prefix needed if there is only one of the first nonmetal.  The second name is the name of the second nonmetal used – it will be shortened with an “IDE” ending and will have a prefix (even if there is only one of it). The second nonmetal always gets a prefix.  Examples:  N 2 OCCl 4  Dinitrogen monoxideCarbon tetrachloride

Binary Acids  A binary acid is an acid that contains hydrogen and one other element.  The general formula for any binary acid is: Hydro-nonmetal-ic acid  Examples:  HCl (aq)HBr (aq)  Hydrochloric acidHydrobromic acid

Ternary Acids  A ternary acid is an acid that contains hydrogen and a polyatomic ion.  The name of the polyatomic ion used in the acid will help us form the name of the acid.  If the polyatomic ion ends in “ate”, the ending of the acid’s name will become “ic”. (I think of the saying “I ate something icky”, to help me keep these straight.)  If the polyatomic ends in “ite”, the ending of the acid’s name will become “ous”.  Examples:  HNO 3 (aq)HNO 2 (aq)H 2 SO 4 (aq)  Nitric acidNitrous acidSulfuric acid

Try Naming These Examples  Li 2 O  FeCl 3  Al 2 (CO 3 ) 3 N2O3N2O3N2O3N2O3  FeCl 2 ·4H 2 O  HF (aq)  PbS 2  NaHCO 3  H 3 PO 4 (aq)  MgCl 2 ·10H 2 O  H 2 SO 3 (aq)  S 2 Br 4  Lithium oxide  Iron (III) chloride  Aluminum carbonate  Dinitrogen trioxide  Iron (II) chloride tetrahydrate  Hydrofluoric acid  Lead (IV) sulfide  Sodium bicarbonate  Phosphoric acid  Magnesium chloride decahydrate  Sulfurous acid  Disulfur tetrabromide

THE END!