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Learn the basics of ionic bonding, including naming conventions and writing formulas for compounds. Practice exercises included. |
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Warm-Up • Tell me everything you know about Ionic Bonding (3 minutes)
Warm-Up 1. If element X has an electronegativity of 2.7 and element Y has an electronegativity of 1.6 the resulting bond is characteristic of a. an ionic bond because the difference in electronegativity is less than 1.7 b. an ionic bond because the difference in electronegativity is greater than1.7 c. a covalent bond because the difference in electronegativity is less than 1.7 d. a covalent bond because the difference in electronegativity is greater than 1.7 2. Which term describes a substance that has a low melting point and does not conduct electricity in either the solid or the liquid form? a. Ionic and molecular b. Ionic and metallic c. Covalent and molecular d. Covalent and metallic
What will we learn? • How to use different naming conventions based upon the type of compound • Standard system for main group ionic cmpds • Stock system for transition metal ionic cmpds • Prefix system for molecules (non-metal/non-metal) • How to write formulas from names • How to calculate percent mass of an element in a compound
Oxidation Numbers • The oxidation number is the charge an atom takes when it loses or gains electrons and becomes an ion. • Oxidation Numbers are based on the number of valence electrons
Chemical Compounds • Atoms are not chemically stable until they have 8 valence electrons (octet rule). • Atoms gain, lose, or share electrons with other atoms to become chemically stable.
Ionic Compounds Crystalline Lattice
Ionic Compounds • Contains a metal and nonmetal • The valence electrons from the metal are transferred to the nonmetal. • Metal is listed first, followed by the nonmetal. • Change the ending of the nonmetal to ~ide. • Examples: sulfide, oxide, phosphide. • Ionic Examples: Example: NaCl Sodium Chloride Example: BaF2 Barium Fluoride Example: AlP Aluminum Phosphide
Standard System Naming Representative Metals: • s block & p block metals • Zn(+2), Cd(+2), Ag(+1) Representative Metals only have 1 oxidation number
Ionic Binary Compound Naming Practice (Standard Naming) • Al2S3 • Ba3P2 • ZnO • Ca2C • Cs3As • Fr2O • Aluminum Sulfide • Barium Phosphide • Zinc Oxide • Calcium Carbide • Cesium Arsenide • Francium Oxide
More Ionic Binary Compounds Naming Practice • FrF • GaCl3 • RaBr2 • Sr3N2 • Ag2O • Mg3P2 • Francium Fluoride • Gallium Chloride • Radium Bromide • Strontium Nitride • Silver Oxide • Magnesium Phosphide
The 5 steps for writing a binary ionic compound formula • Write the symbols of the two elements • Write the oxidation number of each as superscripts. • Drop the positive and negative signs • Crisscross the superscripts so they become subscripts. • Reduce when possible
Formula for Aluminum Oxide • Write the symbols of the elements Al O
Formula for Aluminum Oxide • Write the oxidation numbers for each element +3 -2 Al O
Formula for Aluminum Oxide • Drop the positive & negative sign. 3 2 Al O
Formula for Aluminum Oxide • Crisscross the superscripts so they become subscripts 3 2 Al O
Formula for Aluminum Oxide • Reduce subscripts when possible. (not possible here) Al O 3 2
Examples of Reduction of Subscripts Sr2O2 Al3P3 Pb2O4 Ba3N2 SrO AlP PbO2 Ba3N2
Ionic Binary Compound Formula Practice • Potassium iodide • Lithium bromide • Magnesium oxide • Sodium nitride • Radium phosphide • Strontium chloride • KI • LiBr • MgO • Na3N • Ra3P2 • SrCl2
More Ionic Binary Compound Formula Practice • Rubidium Sulfide • Gallium Fluoride • Thallium Iodide • Cesium sulfide • Aluminum bromide • Potassium Nitride • Rb2S • GaF3 • TlI3 • Cs2S • AlBr3 • K3N
Ionic Binary Compound (Stock Naming) Transition Metals: • d & f blocks • Sn+2 & Sn+4 • Pb+2 & Pb+4
Transition Metals Roman numerals are used in the name of the transition metal in the compound to show the oxidation number of the cation. Examples Mn+4 Manganese (IV) Mn+6 Manganese (VI) Fe+2 Iron (II) Fe+3 Iron (III) Cu+1 Copper(I) Cu+2 Copper (II)
Stock System Naming Compounds are named by the name of the transition metal cation followed by the oxidation number as the roman numeral and then proper name of the anion. Cu2O Copper (I) oxide CuO Copper (II) Oxide
Stock System Nomenclature How does one determine the charge of the transition metal? • Find the charge of the anion • Calculate total negative charges (multiple by number of anions) • Cation must be of equal value but opposite charge • Divide by the number of available cations • Write the roman numeral corresponding to the charge on the transition metal
Stock System Nomenclature Examples: -3 total +3 total +3 -1 • CoCl3 Cobalt (III) chloride
Stock System Nomenclature Examples: -6 total +6 total +2 -3 • Ni3P2 Nickel (II) Phosphide
Stock System Nomenclature Examples: -14 total +14 total +7 -2 • Mn2O7 Manganese (VII) Oxide
Naming binary compounds containing a transition metal • Fe2O3 • NiBr2 • V2O5 • Cu3P2 • PbS2 • MnO2 • Iron (III) Oxide • Nickel (II) Bromide • Vanadium (V) Oxide • Copper (II) Phosphide • Lead (IV) Sulfide • Manganese( IV) Oxide
Naming binary compounds containing a transition metal • Co2S3 • CrI2 • VO2 • SnI4 • Au2S • TiF3 • Cobalt (III) Sulfide • Chromium (II) Iodide • Vanadium (IV) Oxide • Tin (IV) Iodide • Gold (I) Sulfide • Titantium (III) Fluoride
Formulas for Transition Metals Binary Ionic Compounds • Remember: The Roman Numeral IS the oxidation number for the element. Example: Gold (III) Oxide Au2O3
Formulas for Transition Metals • Iron (II) Oxide • Lead(IV) Sulfide • Vanadium (IV) Fluoride • Palladium (II) nitride • Ruthenium (III) iodide • FeO • PbS2 • VF4 • Pd3N2 • RuI3
Polyatomic Ions Polyatomic (many atoms) ions are covalent molecules with a charge. They behave as if they were one-atom ion. 1
Polyatomic Ions Look at pg 7 of your reference sheets. What is the difference between ammonium and the rest of the polyatomics? • Treat polyatomic ions as you would a normal ion – crisscross oxidation numbers to determine the formula. • The only difference is that when you have more than one of a specific polyatomic ion in a formula you must encase it in parenthesis.
Ternary Ionic Compounds • Calcium Nitrate • Magnesium Phosphate • Barium Hydroxide • Sodium Sulfate • Potassium Carbonate • AlPO4 • Ga2(SO4) 3 • CsC2H3O2 • Sr(MnO4)2 • Rb2Cr2O7 • Ca(NO3)2 • Mg3 (PO4) 2 • Ba(OH) 2 • Na2SO4 • K2CO3 • Aluminum Phosphate • Gallium Sulfate • Cesium Acetate • Strontium Permanganate • Rubidium Dichromate
Ionic Mixed Practice Write the name • NH4Cl • CaBr2 • GaP • Rb2CO3 • Mg(NO2)2 • CuSe • FeTe Write the formula • potassium chlorate • gold (I) oxide • cadmium iodate • cesium fluoride • aluminum sulfide • nickel (II) Nitrate • chromium (VI) Nitride
Covalent Compounds Water Molecule Hydrogen Atom Oxygen Atom Hydrogen Atom
Covalent Compounds • Contains 2 or more nonmetals • The valence electrons are shared between the nonmetals. • Must use prefixes in the name. • Name tells you the formula. • Example: N2O4 – dinitrogen tetroxide • You CANNOT reduce the formulas • If the first element is singular there is no prefix. • The second element must ALWAYS have a prefix.
Covalent Prefixes Mono -1 Di – 2 Tri – 3 Tetra – 4 Penta – 5 Hexa – 6 Hepta – 7 Octa – 8 Non – 9 Deca -10 A prefix tells you the number of atoms of that element in the compound.
Naming Covalent Compounds • N2O3 • CH4 • PO5 • S2F4 • P4O10 • Dinitrogen trioxide • Carbon tetrahydride • Phosphorus pentoxide • disulfur tetrafluoride • Tetraphosphorus decoxide
Writing Formulas for Covalent Compounds • CO • PCl5 • SF6 • N2O3 • SO2 • Carbon Monoxide • Phosphorus Pentachloride • Sulfur hexafluoride • Dinitrogen trioxide • Sulfur dioxide
Ionic & Covalent Structure Water Ionic Compounds form a crystalline lattice – repeating pattern of ions. Covalent compounds form individual molecules that are not connected to each other. Na+1 Ions Cl-1 Ions Sodium Chloride
How do I know which naming system to use? Identify the FIRSTelement of the compound as either: • Representative Metal Standard System NaClLiBrAl2O3Ba(OH)2 • Transition Metal Stock System CoCl2CoCl3Cr2O3FeO • Non-metal Prefix System CO2PCl5As2O5NO2 • (ROMAN NUMERALS)
Name These Compounds • PCl3 • Sr3N2 • KOH • NH3 • CrCO3 • Phosphorus trichloride • Strontium Nitride • Potassium Hydroxide • Nitrogen trihydride • Chromium (II) Carbonate
Write formulas for these compounds • Calcium Chromate • Sodium Bromide • Sulfur hexafluoride • Carbon tetrachloride • Potassium Phosphate • CaCrO4 • NaBr • SF6 • CCl4 • K3PO4
Warm-Up – Label the metals as TM, RM, or NM • Aluminum Sulfide ____ _____________ • AsCl5 ____ ______________ • Barium nitride ____ ______________ • FeCl2 ____ ______________ • Calcium hydride ____ ______________ • CCl4 ____ ______________ • Cd3N2 ____ ______________ • Cesium nitride ____ ______________ • Chromium (III) oxide ____ ______________ • Copper (I) sulfate ____ ______________
Examples • HI • ~ide • HCl • ~ide • H2S • ~ide hydroiodic acid hydrochloric acid hydrosulfuric acid
Examples • HNO3 • H2CO3 • H2SO3 nitric acid • ~ate • ~ate carbonic acid sulfurous acid • ~ite
Examples • hydroselenic acid • chromic acid • hypochlorous acid • -ide H2Se • -ate H2CrO4 HClO • -ite