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Chapter 9 Naming Compounds and Writing Formulas

Chapter 9 Naming Compounds and Writing Formulas. Ionic Compounds; Molecular Compounds and Acids. Types of Compounds. Compound- Formed when atoms of two or more elements combine CHEMICALLY. Law of Definite Proportions-

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Chapter 9 Naming Compounds and Writing Formulas

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  1. Chapter 9Naming Compounds and Writing Formulas Ionic Compounds; Molecular Compounds and Acids

  2. Types of Compounds • Compound- Formed when atoms of two or more elements combine CHEMICALLY. • Law of Definite Proportions- In ANY CHEMICAL compound the elements always combine in the same proportion by mass. • This agrees with Dalton’s Atomic Theory that atoms combine in small whole # ratios.

  3. Molecular Compounds • Two Types of Compounds- • Molecular Compounds • Ionic Compounds 1. Molecular Compounds Formed between 2 or more NONMETALS (Covalent Bond- Share Electrons) - Liquid or gas at room temp. and have relatively low melting and boiling points.

  4. Molecule • Molecule- NEUTRAL no charge, group of atoms that act like a unit (one thing) Molecules of a compound are all identical to each other Molecules of different compounds are different. Ex: CO2 (1C : 2 O); CO (1C : 1O)

  5. Molecular Formula Tells the number and kinds of atoms in a molecule of a compound. (CO2 & CO) • Nonmetal + Nonmetal • Covalent Bond: Share Electrons • Diatomic molecules: 7 nonmetallic elements that are always paired and exist a molecules NOT atoms. • MEMORIZE: H O N Cl Br I F Hydrogen H2; Oxygen O2; Nitrogen N2; Chlorine Cl2; Bromine Br2; Iodine I2; Fluorine F2

  6. Ionic Compounds • Metal + Nonmetal • Made up of IONS • Relatively high melting and boiling points • NEUTRAL (ion charges cancel out; total + charge = total – charge)

  7. ION • Atom or group of atoms that have an UNEQUAL number of protons and electrons (#p+ does NOT = #e-) have a + or – charge • Cations- atom or group of atoms with + charge • Metals • Lose electrons • When naming cations the name stays the same as the element. • EX: Na+ = sodium ion; Al+3 = aluminum ion

  8. Cation Charges • ionic charges of Group A metals (see front of periodic chart) • ionic charges of Group B metals (transitional metals) – see back of periodic chart • Roman Numerals – are used to indicate the charge of a transitional metal. • Examples: Copper I = Cu +; Copper II = Cu+2 Lead II = Pb+2; Lead IV = Pb+4

  9. Anions • Atom or group of atoms with a – charge • Nonmetals • Gain electrons • When naming anions the ending changes to “ide” • Ex: chlorine becomes chloride (Cl-); oxygen becomes oxide(O-2); nitrogen becomes nitride (N-3)

  10. Polyatomic Ions • Tightly bound group of atoms that act as a unit (one thing) and carry a charge. • Also called Radicals • Most end in “ite” or “ate”; “ite” ending has one less oxygen than “ate” ending. Examples; chlorite ClO2-1; chlorate ClO3-3 • Except: hydorxide (OH-); cyanide (CN-); ammonium (NH4+). • Hypo – means 1 less oxygen (hypodermic means under the skin) hypochlorite ClO- • Per – means 1 more oxygen perchlorate ClO4-

  11. Formula Unit (FU) • Lowest whole number ration on IONS in an ionic compound. - Ionic Compounds are NOT MOLECULES they are called Formula Units. • Chemical Formula shows the kinds and number of atoms in the SMALLEST UNIT of a compound. • The most positive element (metallic) is written first. EX: H2O = 2 Hydrogen atoms + 1 Oxygen atoms CO2 = 1 Carbon atom + 2 Oxygen atoms

  12. Homework Questions • What are the differences between an ionic compound and molecular compound? (3) • Answer: Ionic- made up of ions; metal + nonmetal; High BP & MP; Formula Unit Molecular- made up of nonmetals; share electrons covalent bonds; usually liquids or gases at room temp.; Molecules

  13. Homework Questions • Why aren’t ionic compounds molecules? • Ionic Compounds are Formula Units (FU’s) and molecules are made up of 2 or more nonmetals • What is the smallest ratio of an ionic compound called? • Formula Unit (FU)

  14. Name the 7 diatomic elements and write their formulas correctly. • Hydrogen; H2 • Oxygen; O2 • Nitrogen; N2 • Chlorine; Cl2 • Bromine; Br2 • Iodine; I2 • Fluorine; F2

  15. Homework Questions cont. • Metals form + ions called ___________. • Nonmetals form - ions called _______. • What group of metals have more than one possible charge? • Group B metals; transitional metals • What is a polyatomic ion? • A group of atoms that act as a single unit and carry a charge.

  16. Naming compounds and Writing Formulas Sodium chloride • Binary compound- • Simplest compound made up of 2 elements • Examples: [ – NaCl ] • [iron II chloride – ] • (NAMING) 1.) element with the positive ionic charge is written first. ( ) • Group A Metals – metal name is written. Example Na+ = sodium • Group B Metals ( ) – • Examples : Fe+2 = Iron II • Hg+ = ____________ • Sn+4 = ____________ • ** Use the back of your periodic chart (Common Metal Ions with more than 1 ionic charge!) FeCl2 metals Roman Numeral Indicates the charge. Transitional Mercury I Tin IV

  17. nonmetal • 2.) element with the negative ionic charge is written next. ( ) • Change the ending of the nonmetal to ( ) • Nonmetal marries the metal and changes its name to “ide” like a bride. • Examples: chlorine – chloride • Bromine - ________________ • Oxygen - ________________ ide bromide oxide

  18. USE THE RULES ABOVE TO NAME THE BINARY IONIC COMPONDS BELOW: • 1. MgO______________ 5.) FeCl3 ____________ • 2. BaS ______________ 6.) SnBr4 ____________ • 3. Na3N _____________ 7.) K3P ____________ • 4. Cu2O _____________ 8.) PbS ____________ Magnesium oxide Iron III chloride Barium Sulfide Tin IV bromide Sodium nitride Potassium phosphide Copper I oxide Lead II sulfide

  19. WRITING FORMULAS • 1.) write the ion for the metal first • Group A Metals –Examples: Lithium – Li + • Aluminum - ___ Magnesium - ___ Rubidium - ___ • Group B Metals – • Examples: Tin II – Sn+2 • Copper I - ____ Mercury II - ____ Lead IV - ____ Al+3 Mg+2 Rb+1 The Roman Numeral indicates the charge Hg+2 Cu+1 Pb+4

  20. write the ion for the non-metal • Group VA, VIA, VIIA • The number of the charge = • Examples: sulfide = 8 – 6 = 2 ion = • phosphide = ______ • Iodide = _____ 8 – the groupA number S-2 P-3 I-

  21. Cross-Over-Method • Place the charge number of the metal as the subscript to the nonmetal and the charge number of the nonmetal as the subscript to the metal. • You must reduce the charges if you can. • Examples: • Lithium Fluoride Magnesium Fluoride Potassium Sulfide Copper I Chloride Aluminum Nitride Chromium III Sulfide Li+ F- = LiF Mg+2 F- =MgF2 K+ S-2 = K2S Cu+ Cl- = CuCl Al+3N-3 = AlN Cr+3 S-2 = Cr2S3

  22. USE THE RULES ABOVE TO WRITE FORMULAS FOR THE BINARY IONICCOMPOUNDS: • Calcium Fluoride __________ Rubidium Iodide ___________ • Sodium Phosphide ________ Strontium chloride__________ • Mercury I Oxide ___________ Tin II Sulfide______________ • Iron III nitride _____________ Copper I Selenide___________ Ca+2 F- = Rb+ I- = CaF2 RbI Na+P3 Sr+2 Cl- = Na3P SrCl2 Hg+ O-2 = Sn+2 S-2 = Hg2O SnS Fe+3 N-3 = Cu+ Se-2 = FeN Cu2Se Classwork and homework worksheet 2 & 3 Binary Ionic Compounds.

  23. Ternary Compounds Ionic • Ternary Compounds are _________ and contain a _____________________. • POLYATOMIC ION – •  A group of atoms that act as a single unit and carry a charge. • Polyatomic ions end in “ “ or “ “ EXCEPTIONS: (OH)- • (CN)- • *only (+) poly atomic ions (NH4)+ (PH4)+ Polyatomic Ion ite ate hydroxide cyanide ammonium phosphonium

  24. (Naming) Rules are similar to Binary ionic compounds. • Element with positive ionic charge is written first. ( ) •  Group A Metals: name simply written Ex. Ca2+ - •  Group B Metals: need a roman numeral Ex. Pb2+ _________ cation calcuim Lead II

  25. radical • 2. Polyatomic ion ( ) written next. • Write the name as it appears on the back of the Periodic Chart. • Ex. (C2H3O2)- • (Cr2O7)2- • Naming Examples: LiCO3 • Be(CN)2 • Sn(SO4)2 acetate dichromate Lithium carbonate Beryllium cyanide Tin IV sulfate

  26. Magnesium sulfate • USE THE RULES ABOVE TO NAME THE TERNARY IONIC COMPOUNDS BELOW: • MgSO4 ___________________________ • NaNO3____________________________ • CaCO3 ___________________________ • NaOH __________________________ • Ba(ClO2)2 ________________________ Sodium nitrate Calcium carbonate Sodium hydroxide Barium chlorite

  27. Ternary Naming Continued Iron III tartrate • Fe2(C4H4O6)3 __________________ • (NH4)3PO4 ________________________ • Cu2CrO4 __________________________ • Hg(NO2)__________________________ • Al2(SO4)3 __________________________ Ammonium phosphate Copper I chromate Mercury I nitrite aluminum sulfate

  28. Writing Ternary Ionic Formulas • Write the ion for the metal first. • Group A Metals – • Ex. Calcium • Rubidium • Boron • Group B Metals – The Roman Numeral tells you the charge number. • Ex. Iron III Lead IV • Mercury I Tin II Group # = charge Group 2 = Ca +2 Group 1 = Rb +1 Group 3 = B +3 Fe +3 Pb+4 Hg +1 Sn +2

  29. Write the polyatomic ion next (USE PARENTHESIS) • *Remember polyatomic ions end in “ “ or “ “ • except (OH)- and (CN)- • Examples: • Sulfite • Carbonate • Phosphate • Nitrite ite ate hydroxide cyanide SO3-2 CO3-2 PO4-3 NO2-

  30. Cross-Over-Method • write the charge number of the metal as the subscript of the polyatomic ion. (You MUST use PARENTHESIS if the subscript is 2 or greater but DO NOT use Parenthesis if the subscript is 1) • 2. write the charge number of the polyatomic ion as the subscript of the metal. *You must reduce if you can but NEVER change the polyatomic ion!! DO NOT TOUCH THE POLYATOMIC ION !! • DO NOT CHANGE THE FORMULA OF THE POLYATOMIC ION !! • Examples: Magnesium nitrate • Aluminum sulfate • Iron II sulfite • Iron III sulfite • Tin IV nitrate

  31. DO NOT TOUCH THE POLYATOMIC ION • DO NOT CHANGE THE FORMULA OF THE POLYATOMIC ION !! • Examples: • Magnesium nitrate • Aluminum sulfate • Iron II sulfite • Iron III sulfite • Tin IV nitrate Mg+2 NO3- = Mg(NO3)2 Al+3 SO4-2 = Al2(SO4)3 Fe+2 SO3-2 = FeSO3 Fe+3 SO3-2 = Fe2(SO3)3 Sn+4 NO3- = Sn(NO3)4

  32. USE THE RULES ABOVE TO WRITE TERNARY FORMULAS FOR THE COMPOUNDS +1;-2 (NH4)2S • Ammonium sulfide __________________ • Silver chromate ____________________ • Iron III tartrate _____________________ • Beryllium hydroxide ________________ • aluminum oxalate _________________ • Copper I cyanide ___________________ • Nickel carbonate ___________________ +1;-2 Ag2CrO4 +3;-2 Fe2(C4H4O6)3 +2;-1 Be(OH)2 +3;-2 Al2(C2O4)3 +1;-1 CuCN +2;-2 NiCO3

  33. Molecular Compounds Writing names and Formulas

  34. Molecular Compounds • Made up of 2 or more NONMETALS (NO METALS or IONS) • Share electrons when bonding • Sharing Electrons is called COVALENT BONDING • The smallest unit of a molecular compound is called a MOLECULE.

  35. (NAMING) To write the name, write 2 words • 1.) the non-metal closest to the metals on the periodic chart is written first. • 2.) Prefixes are used to tell how many atoms of each element are in the compound. • 1 6 • 2 7 • 3 8 • 4 9 • 5 10 hexa mono di hepta tri octa tetra nona penta deca

  36. Exception: don’t write mono- if there is only one of the first element. • 3.) The second element always uses a prefix and ends in “ _ide ”. • 4.)No double vowels when writing names (oa, oo) Ex. CO carbon monoxide CO2 carbon dioxide P2O5 diphosphorus pentoxide

  37. Name These • N2O • Dinitrogen monoxide • NO2 Nitrogen dioxide • Cl2O7 Dichlorine heptoxide • CBr4 • Carbon tetrabromide • SiO2 silicon dioxide P2O3 Diphosphorus trioxide

  38. (FORMULA WRITING) NO CRISS CROSSING Examples: Phosphorous pentachloride - PCl5 Dinitrogen trisulfide – N2S3 NO3 CF4 Nitrogen trioxide _________ carbon tetrafluoride _______ Diiodine decachloride _____ phosphorous triiodide ______ Sulfur hexabromide _______ nitrogen pentafluoride ______ Diphosphorous trisulfide ____ carbon tetrabromide ______ I2Cl10 PI3 SBr6 NF5 P2S3 CBr4

  39. Acids Writing names and Formulas

  40. Acids • Compounds that give off hydrogen ions when dissolved in water. • Must have H in them. • will always be some H next to an anion. • The anion determines the name.

  41. Naming acids • If the anion attached to hydrogen is ends in -ide, put the prefix hydro- and change -ide to -ic acid • HCl - hydrogen ion and chloride ion • hydrochloric acid • H2S hydrogen ion and sulfide ion • hydrosulfuric acid

  42. Naming Acids • If the anion has oxygen in it • it ends in -ate or -ite • change the suffix -ate to -ic acid • HNO3 Hydrogen and nitrate ions • Nitric acid • change the suffix -ite to -ous acid • HNO2 Hydrogen and nitrite ions • Nitrous acid

  43. Name these • HF • H3P • H2SO4 • H2SO3 • HCN • H2CrO4 Hydrofluoric acid Hydrophosphoric acid sulfuric acid sulfurous acid hydrocyanic acid chromic acid

  44. Writing Acid Formulas/Naming • Hydrogen will always be first • name will tell you the anion • make the charges cancel out • Starts with hydro- if no oxygen in the acid, -ide ending becomes –ic Ex. HCl = hydochloric acid • no hydro, -ate ending from polyatomic ion becomes -ic, H2SO4 = sulfuric acid -ite ending becomes –ous, H2SO3 = sulfurous acid

  45. Write formulas for these • hydroiodic acid • acetic acid • carbonic acid • phosphorous acid • hydrobromic acid HI HC2H3O2 H2CO3 H3PO3 HBr

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