Chapter 9 Chemical Names and Formulas Ms. Wang Lawndale High School

Monatomic Ions Consist of a single atom with a positive or negative charge Polyatomic Ions Composed of more than one atom –Example: Li +, Na +, K +, Cl -, Ca 2+, Mg 2+, F -, S 2- –Which ones are cations? Which ones are anions? The entire unit is comprised of one charge Example: SO 4 2-, NO 2 -, ClO 2 - Chapter 9.1 – Naming Ions

Chapter 9.2 – Naming Ionic Compounds Binary Compound – composed of 2 elements

Write the cation first and then the anion Cation keeps its name Anion changes its ending The correct formula contains the fewest positive and negative ions needed to make the electrical charge ZERO. Rules for Naming Chemical Formulas

Anion changes its ending… –ine, From -ygen, To -ide -fur, -ogen Fluorine becomes fluoride Oxygen becomes oxide Example: Write the chemical formula for Calcium Chloride NameCationAnionTotal number of ions Chemical Formula Calcium chloride Ca 2+ Cl - 3 CaCl 2

Practice 1.Cs 2 O 2.SrF 2 3.SnS 4.KBr 5.CuO 6.NaI 7.K 2 S 8.CaO Cesium Oxide Strontium Fluoride Tin (II) Sulfide Potassium Bromide Copper (II) Oxide Sodium Iodide Potassium Sulfide Calcium Oxide

How to Write Formulas for Ionic Compounds Question: What is the formula for aluminum oxide? Step 1: Write the symbol and charges for the cation and anion Aluminum =Al 3+ Oxygen = O 2- Step 2: Write the symbol for the ions side by side, beginning with the cation Al 3+ O 2- Step 3: Find the least common multiple of the ions’ charges. The least common multiple of 2 and 3 is 6. To be neutral you would need 6 + and 6- To get 6+, you need two Al 3+ ions To get 6-, you need three O 2- ions Al 2 O 3

How to Write Formulas for Ionic Compounds Example: what is the formula for Magnesium Chloride? CHEATER METHOD: JUST CRIS-CROSS!!!! 1.Magnesium =Mg 2+ Chloride =Cl - 2.Mg 2+ Cl - 3. Least common multiple of 2 and 1 = 2 To get 2+, need one Mg To get 2-, need two Cl MgCl 2

Transition Metals For metals with more than one charge, the charge on the metal ion must be stated. These are typically transition metals. Example Write the name of TiO? Ex. Iron (II) Chloride Fe 2+ Cl -  FeCl 2 Ex. Iron (III) Chloride Fe 3+ Cl -  FeCl 3 1.Find out the charge on the ion that only has one charge. 2. Then evaluate what charge the other ion must have in order to fulfill the formula. Ti must be 2+ Titanium (II) Oxide O 2-

Practice Write the formulas for the following compounds: 1.CuCl 2 2.CuCl 3.Cr 2 O 3 4.MnO 5.BeCl 2 6.NaF Copper (II) Chloride Copper (I) Chloride Chromium (III) Oxide Manganese (II) Oxide Beryllium Chloride Sodium Fluoride

Polyatomic Ions Polyatomic Ions: ions made from more than one element. They stay together when bonding. Example: Lithium Phosphate Li + PO 4 3- Li 3 PO 4 Example: Magnesium Hydroxide Mg 2+ OH - Mg(OH) 2

Write the Formula for the following 1.Calcium Nitrate 2.Iron (III) Sulfate 3.Copper (II) Sulfite 4.Potassium Permanganate 5.Chromium (III) Nitrate 6.Sodium Perchlorate 7.Calcium Acetate 8. Magnesium Dichromate Ca(NO 3 ) 2 Fe 2 (SO 4 ) 3 CuSO 3 KMnO 4 Cr(NO 3 ) 3 NaClO 4 Ca(C 2 H 3 O 2 ) 2 MgCr 2 O 7

Name the following Compounds 1.Mg(OH) 2 2.Ti 2 (CrO 4 ) 3 3.CoPO 4 4.AgNO 3 5.CuSO 4 6.BeC 2 O 4 7.FeCrO 4 8. CrPO 4 Magnesium Hydroxide Titanium (III) Chromate Cobalt (III) Phosphate Silver Nitrate Copper (II) Sulfate Beryllium Oxalate Iron (II) Chromate Chromium (III) Phosphate

Chapter 9.3 – Naming Molecular Compounds the prefix in the name of a binary molecule tells how many atoms of each element are present in each molecule of the compound Remember that molecules are composed of two nonmetals

Naming Molecular Compounds PREFIXNUMBER Mono-1 Di-2 Tri-3 Tetra-4 Penta-5 Hexa-6 Hepta-7 Octa-8 Nona-9 Deca-10

Writing Formulas for Binary Molecular Compounds 1 st Step: Write the cation 2 nd Step: Write the anion with the appropriate prefix Example #1: NCl 3 Nitrogen Trichloride Example #2: BCl 3 Example #3: N 2 O 3 Example #4: N 2 H 4 Boron Trichloride Dinitrogen Trioxide Dinitrogen Tetrahydride

Practice (1.) SO 3 (2.) CS 2 (3.) Cl 2 O 7 (4.) Carbon Tetrabromide (5.) Diphosphorus Trioxide (6.) Phosphorus Pentachloride (7.) Iodine Heptafluoride (8.) Chlorine Trifluoride (9.) Iodine Dioxide Sulfur Trioxide Carbon Disulfide Dichlorine Heptaoxide CBr 4 P2O3P2O3 PCl 5 IF 7 ClF 3 IO 2

Chapter 9.4 – Naming Acids and Bases Acids – compound that contains one or more hydrogen atoms and produces hydrogen ions (H + ) Bases – compound that produces hydroxide ions when dissolved in water (OH - )

Rules for Naming Acids (memorize) Anion Ending ExampleAcid Name Example -ideChloride (Cl - ) Hydro---- ic acid Hydrochloric Acid -iteSulfite (SO 3 2- ) ----ous acid Sulfurous Acid -ateNitrate (NO 3 - ) ----ic acidNitric Acid Rules for naming bases are the same as Ionic Compounds

Practice (1.) HNO 3 (2.) HMnO 4 (3.) HCN (4.) H 2 S (5.) LiOH (6.) Pb(OH) 2 (7.) Mg(OH) 2 (8.) Al(OH) 3 Nitrous Acid Permanganic Acid Hydrocyanic Acid Hydrosulfuric Acid Lithium Hydroxide Lead (II) Hydroxide Magnesium Hydroxide Aluminum Hydroxide

Homework Section 9.1 – Page 258 #’s 1-9 Section 9.2 – Page 266 #’s Section 9.3 – Page 270 #’s Section 9.4 – Page 273 #’s Chapter 9 Assessment Page 281 #’s 42-61, 65-70, 82, 83