Chemical Nomenclature Section 2.2

-system used in chemistry to name compounds Nomenclature -system used in chemistry to name compounds Ionic Compounds Covalent Compounds

Naming Ionic Compounds Binary compounds and Polyatomic compounds

Binary Compounds Binary Compounds- are inorganic compounds that contain 2 elements Write the full name of the cation (metal) Write the root of the anion (non-metal) next to the cation Write the ending –ide next to the root of the anion Ex: AlCl3 = aluminum chlorine  Aluminum chloride

Transition Metal Ions Some elements may form more than one cation (ions with different charges), these are called multivalent ions. You will indicate the charge of the ion by writing the charge in roman numerals after the cation name Use the cross up rule to find charges! Ex: Fe2O2 and Fe2O3 ______________ and ______________

Multivalent (Two Valences) Element Ion Stock System Classical System Copper Cu+ Copper (I) cuprous Cu 2+ Copper (II) cupric Mercury Hg+ mercury (I) mercurous Hg2+ mercury (II) mercuric Lead Pb2+ lead (II) plumbous Pb4+ lead (IV) plumbic

Example of Multivalents Write the name using the classical system and the stock system for the following: HgO PbO2 Write the chemical formula from the following names. Cobaltic iodide stannous fluoride

Polyatomic Compounds Polyatomic Ions- compounds that contains 3 elements (often called tertiary compounds).

Polyatomic Ions you should know! Common Polyatomics OH-  Hydroxide NO2-  Nitrite SO32-  Sulfite ClO2 -  Chlorite ClO3-  Chlorate CO32-  Carbonate NO3-  Nitrate SO42-  Sulfate PO43-  Phosphate Weird Polyatomics CN-  Cyanide CH3COO-  Acetate NH4+  Ammonium Page 98 Table 3.4 MORE TO KNOW 

Naming Polyatomic Ionic Compounds Naming a polyatomic ionic compound is a similar process to naming a binary compounds only the ending of the anion is given from the chart …and does not change! Examples: Ca(ClO2)2  Calcium Chlorite Ca(ClO3)2  Calcium Chlorate

Naming Molecular Compounds

Molecular Compounds Molecular compounds= 2 non-metals The system of naming molecular compounds is based on the use of prefixes

Pre-fixes you need to know 1  Mono- 2  Di- 3  Tri- 4  Tetra- 5  Penta- 6  Hexa- 7  Hepta- 8  Octa- 9  Nona- 10  Deca-

Naming Molecular Compounds Prefixes are used to designate how many atoms of each element are present. RULES: NOTE: The prefix mono- is not used with the first elements name. The first element is named with the appropriate prefix The second element’s root name with the appropriate prefix and ending -ide

Examples Name the compound: N2O4 2 Nitrogens  Di-nitrogen 4 Oxygens  Tetra – oxy – ide Dinitrogen Tetraoxide Name the compound: SO2 1 Sulfur  Sulfur 2 Oxygens  Di – oxy – ide Sulfur Dioxide

Naming Acids (Chapter 10)

General Formula: HX (aq) Naming Acids: Rules There are 2 main kinds of acids: 1.binary acids 2. oxoacids Binary Acids- composed of 2 elements Hydrogen + non-metal General Formula: HX (aq) Examples: HF (aq) =hydrofluoric acid HCl (aq) = hydrochloric acid

Naming Binary Acids If the name of the anion ends in “–ide”, the acid name begins with the prefix “hydro-”, then the stem of the anion is given and finally the suffix “-ic” is added and is followed by the word “acid”. Example: H2S (aq) (anion: sulfide)  hydro + stem + ic + acid Hydrosulfuric Acid

How do you know when to do this? Naming Binary Acids Every acid formula starts with “H”, as the cation. To name an acid, look at the anion the hydrogen is bonded to. Name: HCl (aq) =hydrochloric acid Prefix + root name of non-metal + suffix + “acid” Hydro + chlor + ic + acid How do you know when to do this?

General Formula: HXOn (aq) What about these? H2S anion = sulfide ion H2SO3 anion = sulfite ion H2SO4 anion = sulfate ion Add one more “O” Oxoacids- an acid formed from a polyatomic ion. Hydrogen + Oxygen +Element General Formula: HXOn (aq) Examples: HClO4 (aq)

“ITE”  “OUS” Naming Oxoacids If the name of the anion ends in “–ite”, the acid name is the stem of the anion with the suffix “–ous” and is followed by the word “acid”. H2SO3 (aq) Stop and think about the anion SO32- (anion: sulfite)  stem + ous + acid Sulfurous Acid

“ATE”  “IC” Naming Oxoacids If the name of the anion ends in “–ate”, the acid name is the stem of the anion with the suffix “–ic” and is followed by the word “acid”. H2SO4 (aq) Stop and think about the anion SO42- (anion: sulfate)  stem + ic + acid) Sulfuric Acid

Adding Oxygens Polyatomic Ion Prefix Suffix + acid hypo ous acid - ClO- hypo ous acid ClO2- - ClO3- ic acid ClO4- per

Writing Formulas/Naming Acids Remember the following statements… “I ate it and it was icky.” -ate becomes -ic “Rite ous” as (Righteous) -ite becomes -ous

Naming Acids Flowchart Does the formula contain Oxygen? No=Binary Acid Yes=Oxoacid Hydro “stem”ic acid Anion end in __ ? “ate” “ite” “stem”ic acid “stem”ous acid

Writing Formulas for Acids If the name starts with “hydro” Hydroselenic Acid Write the hydrogen ion with charge. H+1 Write the anion with the proper charge. Se-2 Balance the charges using subscripts. H2Se (aq)

Writing Formulas for Acids If the name contains the suffix “–ous” Nitrous Acid Write the hydrogen ion with charge. H+ Look up the polyatomic ion (nitrite) and write it with the correct charge. NO2- Balance the charges using subscripts. HNO2

Writing Formulas for Acids If the name contains the suffix “–ic” without the prefix “hydro” Phosphoric Acid Write the hydrogen ion with charge. H+ Look up the polyatomic ion (phosphate) and write it with the correct charge. PO4-3 Balance the charges using subscripts. H3PO4

Naming Bases Bases are named using the traditional ionic naming system. Metal name + polyatomic ion name Examples: Ca(OH)2 = calcium hydroxide NaOH = sodium hydroxide Al(OH)3 = aluminum hydroxide

Writing Base Formulas Base formulas are written using the traditional ionic system. Look up the metal ion. Write the symbol with the proper charge. Ca+2 Look up the polyatomic ion. With bases, this will always be hydroxide, OH-1. Balance the charges using subscripts. Ca(OH)2