Naming and Formula Writing Nomenclature Naming and Formula Writing

Nomenclature A term that describes the system of principles, procedures, rules, or terms related to naming. We use nomenclature to have a uniform set of rules for naming and writing formulas for chemical compounds. The IUPAC (International Union of Pure and Applied Chemistry) establishes these rules.

Review of Key Vocabulary Ionic Compounds – contain bonds between metals and nonmetals A bond involving a TRANSFER of electrons A bond between cations and anions Cation – An atom that has lost one or more electrons. It has a positive (+) charge. Anion – An atom that has gained one or more electrons. It has a negative (-) charge.

More Key Vocabulary Binary Compound – A substance that has only 2 different elements. MgCl2 NaCl H2O Ternary Compound – A substance that has 3 or more different elements. NaOH H2SO4 CH3Cl

More Key Vocabulary Prefix – A few letters placed at the beginning of a word to change its meaning. Nonmetal Carbon dioxide – CO2 Carbon monoxide – CO

More Key Vocabulary Ending / Suffix – A few letters placed at the end of a word to change its meaning. Laughable Portable Calcium Sulfate – CaSO4 Calcium Sulfite – CaSO3 Calcium Sulfide – CaS Calcium Oxide - CaO

Ionic Nomenclature Always write the cation and then the anion. NaCl – NEVER ClNa Sodium Chloride – NEVER Chloride Sodium

Binary Ionic Nomenclature (Formula  Name) 1-State the name of the cation 2-State the name of the anion For single elements, drop the ending, substitute the suffix –ide Cl = Chlorine  Chloride F = Fluorine  Fluoride Br = Bromine  Bromide I = Iodine  Iodide O = Oxygen  Oxide S = Sulfur  Sulfide N = Nitrogen  Nitride P = Phosphorus  Phosphide C = Carbon  Carbide

Practice Binary Ionic Naming CaCl2 – Calcium chloride MgO – Magnesium oxide AlF3 – Aluminum fluoride SrBr2 – Strontium bromide Ba3N2 – Barium nitride

More Key Vocabulary Subscript – A number that is written smaller and to the lower right of an element or group of elements telling you how many of that element or group there are. H2O Mg(ClO3)2

More Key Vocabulary Superscript – A number that is written smaller and to the upper right of an element or group of elements telling you the charge of the element or group of elements. H3O+ Ca+2 SO4-2 N+3

Binary Ionic Nomenclature (Name  Formula) A little more difficult 1 - Write the symbol of cation and anion including charge 2 - Use subscripts to balance the charge of the compound do not need to write a 1 – it is assumed All ionic compounds have a neutral charge

Binary Ionic Nomenclature (Name  Formula) Calcium Bromide Ca+2 Br- There is a +2 charge and a -1 charge An extra -1 charge is needed Ca+2 Br- Br- +2 -1 -1 = 0 Need 1 calcium and 2 bromine CaBr2

“Crisscross” Method Check Work Charge of the cation becomes the subscript for anion Charge of the anion becomes the subscript for the cation Aluminum Sulfide Al+3 S-2  Al2S3 Notice the + or – charge is dropped Simplify to smallest whole numbers Mg+2 O-2  Mg2O2  MgO Check Work

Practice Binary Ionic Formula Writing Calcium Sulfide – CaS Barium Chloride – BaCl2 Lithium Fluoride – LiF Aluminum Nitride – AlN Sodium Phosphide – Na3P

More Key Vocabulary Transition Element – An element in group 3 through 12 on the periodic table. Oxidation State – A possible charge for an ion of a given element. Located in top right corner of element square on PT All “free elements” have oxidation states of ZERO Many elements only have one oxidation state Many (BUT NOT ALL) transition elements have more than one oxidation state Can have different charges! Some, but only a few, other metals have multiple oxidation states

More Key Vocabulary Roman Numerals – A numeral system established in ancient Rome. The system is based on certain letters which combine to signify a number. 1 = I 2 = II 3 = III 4 = IV 5 = V 6 = VI 7 = VII

Binary Ionic Nomenclature Multiple Oxidation States (Formula  Name) Name the Cation In Parenthesis, write the oxidation number of the cation using Roman Numerals Name the Anion Examples: Iron (II) oxide, Iron (III) oxide

Determining Oxidation Number Based on Formula We will use the “Multiply Down, Add Across” Method First, rewrite the formula Second, below each element, write the number of each element Third, write any known charges, or write an “x” for an unknown charge We typically know the charges for nonmetals Group 15 = -3 Group 16 = -2 Group 17 = -1 Fourth, multiply down, and then create an algebraic expression so you may add across.

Multiply Down, Add Across Fe2O3 FeO Charge of the Compound (Always 0, unless it is an ion) # of each element 2 3 1 1 Known Charges X -2 X -2 2X + -6 = 0 X + -2 = 0 Solve 2X = +6 X = +2 X = +3 The oxidation state of Fe is +3 The oxidation state of Fe is +2 Iron (III) oxide Iron (II) oxide

Practice Binary Ionic Naming Using Elements w/ Practice Binary Ionic Naming Using Elements w/. Multiple Oxidation States MnBr4 – Manganese (IV) bromide CoCl3 – Cobalt (III) chloride Cr2O3 – Chromium (III) oxide Ni3N2 – Nickel (II) nitride TiS2 – Titanium (IV) Sulfide Check to make sure the oxidation state you think is correct is a possible oxidation state according to your periodic table

Practice Binary Ionic Formula Writing Using Elements w/ Practice Binary Ionic Formula Writing Using Elements w/. Multiple Oxidation States Easier than naming Use the “crisscross” method Remember to reduce subscripts… Manganese (VII) sulfide – Mn2S7 Chromium (VI) phosphide – CrP2 Copper (II) chloride – CuCl2 Platinum (IV) Oxide – PtO2

Final Key Vocabulary Polyatomic Ion – A particle that contains more than one atom and has a positive or negative charge. Table E First 3 are cations, the rest are all anions

Ternary Ionic Nomenclature (Formula  Name) Same Rules Write Cation first, then Anion Polyatomic Ions have their own endings NaClO2 = Sodium chlorite

Practice Ternary Ionic Naming AgNO3 – Silver nitrate CaSO4 – Calcium sulfate Na2S2O3 – Sodium thiosulfate Zn3(PO4)2 – Zinc phosphate KMnO4 – Potassium permanganate Hg2O – Dimercury (I) oxide NH4Cl – Ammonium chloride NH4OH – Ammonium hydroxide

Ternary Ionic Nomenclature (Name  Formula) Trickiest of them all… 1 - Write the symbol of cation and anion including charge This may mean a whole polyatomic ion 2 - Use subscripts to balance the charge of the compound do not need to write a 1 – it is assumed 3 - Any subscripts for a polyatomic ion need to be written outside parenthesis that surround the polyatomic ion. May still use “crisscross” method

Ternary Ionic Nomenclature (Name  Formula) Aluminum Sulfate Al+3 SO4-2 There is a +3 charge and a -2 charge We need 2 +3 charges and 3 +2 charges Al+3 Al+3 SO4-2 SO4-2 SO4-2 +3 +3 -2 -2 -2 = 0 Need 2 aluminums and 3 sulfates Al2(SO4)2

“Crisscross” Method w/. Polyatomic Ions Charge of the cation becomes the subscript for anion Charge of the anion becomes the subscript for the cation Iron (II) hydroxide Fe+2 OH-  YOU NEED PARENTHESIS There are not 2 H’s, there are 2 OH’s Simplify to smallest whole numbers Ca+2 S2O3-2  Ca2(S2O3)2  Check Work Fe(OH)2 CaS2O3

Practice Ternary Ionic Formula Writing Calcium Sulfite – CaSO3 Ammonium sulfide – (NH4)2S Cobalt (III) phosphate – CoPO4 Copper (II) nitrate – Cu(NO3)2 Ammonium dichromate – (NH4)2Cr2O7

Ionic Nomenclature Mega Practice Ca3(PO4)2 Calcium phosphate NaOH Sodium hydroxide FeCl3 Iron (III) chloride CuSO3 Copper (II) sulfite KCN Potassium cyanide KBr Potassium bromide Sodium sulfide Na2S Barium nitride Ba3N2 Copper (II) peroxide CuO2 Manganese (VII) oxide Mn2O7 Strontium perchlorate Sr(ClO4)2 Chromium (III) nitrite Cr(NO2)3

More Key Vocabulary Covalent Compounds – contain bonds between one or two nonmetallic elements Remember when Ionic Bonding was so short and easy, and Covalent Bonding was so long and tough? OPPOSITE HERE Naming Covalent Compounds is EASY

Covalent Prefixes # atoms Prefix 1 -mono 6 -hexa 2 -di 7 -hepta 3 -tri Only hard part: You need to MEMORIZE these prefixes # atoms Prefix 1 -mono 6 -hexa 2 -di 7 -hepta 3 -tri 8 -octa 4 -tetra 9 -nona 5 -penta 10 -deca

Covalent Nomenclature (Formula  Name) Name the elements in the order they are listed Use the prefixes to show how many of each element DON’T use “mono” for the first element Avoid difficulty saying words by eliminating “ao” or “oo” by just using “o” Hexaoxide is too difficult to say, just write Hexoxide Change the ending of the second element to -ide

Covalent Nomenclature Practice (Formula  Name) N2O – Dinitrogen monoxide NO2 – Nitrogen dioxide CO – Carbon monoxide CO2 – Carbon dioxide CCl4 – Carbon tetrachloride NI3 – Nitrogen triiodide ***NH3 – Ammonia ***H2O – Water CS2 – Carbon disulfide N2O5 – Dinitrogen pentoxide *** There are common names for these we use instead, H2O you should know, NH3 is in your reference table…

Covalent Nomenclature (Name  Formula) Even Easier! Use the prefixes to guide you for what the subscripts need to be Dihydrogen monosulfide Di = 2  H2 Mono = 1  S H2S

Covalent Nomenclature Practice (Name  Formula) Carbon tetrabromide – CBr4 Iodine dioxide – IO2 Phosphorus pentachloride – PCl5 Dichlorine heptoxide – Cl2O7 Diphosphorus trioxide – P2O3

Ionic + Covalent Nomenclature The trick to naming and formula writing is determine first if the example is an ionic or covalent compound. Covalent P4O10 Dinitrogen monoxide TiCl3 Ammonium thiosulfate Calcium Phosphate Ammonia Covalent Tetraphosphorus decoxide N2O Ionic Ionic Titanium (III) chloride (NH4)2S2O3 Ionic Covalent Ca3(PO4)2 NH3