IONIC BONDING Final Grade Review on martboard eating Change Final Book Accountability Tell them about syllabus change Go over new lunches for classes CHAPTER OPENER Why does hard water bubble less than distilled water? Minerals decrease the effectiveness of the detergent. Atoms and Ions Atoms are electrically neutral. Because there is the same number of protons and electrons. Ions are atoms, or groups of atoms, with a charge (positive or negative) They have different numbers of protons and electrons. Only electrons can move, and ions are made by gaining or losing electrons. ionic compounds consist of a combination of cations and anions the sum of the charges on the cation(s) and anion(s) in each formula unit must equal zero The ionic compound NaCl 2.6 1
An Anion is A negative ion. Has gained electrons. Nonmetals can gain electrons. Charge is written as a superscript on the right. F O Has gained one electron (-ide is new ending = fluoride) Gained two electrons (oxide) A positive ion. A Cation is Formed by losing electrons. More protons than electrons. Metals can lose electrons 1+ Has lost one electron (no K name change for positive ions) Ca 2+ Has lost two electrons Number Line Common Multiple 2 F -4-3 -2-1 0 +1 +2 +3 +4 Penny Example Ca 2+ Breathing Example Common Multiple 2 Ca 2+ 2(F ) WHAT DETERMINE A CATION OR AN ANION THE PATH OF LEAT REITANCE TO BEING NOBLE (AKA LE ENERGY) 2
Why do elements form compounds in the first place? Bonding lowers the potential energy between positive and negative particles. BONDING BALANCE THING There are two major types of bonding between elements: 1. ionic bonds result from a transfer of electrons from one species (usually a metal) to another (usually a nonmetal or polyatomic ion). 2. covalent bonds result from the sharing of electrons by two or more atoms (usually nonmetals). IONIC BOND CLIP We will use NaCl (salt) as our main example of an ionic reaction eawater is 3% NaCl Number Line -4-3 -2-1 0 +1 +2 +3 +4 Teeter Totter Example Octet Rule (Rule of 8) When 2 or more atoms combine, they tend to get a complete, outermost shell with 8 electrons. Atoms try to fill valence shell by gaining, losing, or sharing electrons during reactions. ++++++++++++++++++++++++++ Na In a reaction, sodium loses an electron, has unequal numbers of electrons and protons. Because it now has one more proton than electron, it has a charge of 1 +. If electrons are lost from an atom, positive ions are formed. It takes Ionization Energy To Make This Happen - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - Cl In a reaction, chlorine gains an electron, so it now now has one more electron than proton. It therefore has a charge of 1 - If electrons are gained by an atom, negative ions are formed A negative ions are called anions. 3
CRYTAL LATTICE FORMATION OF NaCl CLIP Ionic Bonding The oppositely charged ions attracted to each other by electrostatic forces Joined by an ionic bond (ions)3-d structure called a crystal (cations surrounded by anions v v) Each Na+ and Cl ion has 6 of the oppositely charged ions clustered around it. Naming Overview Cation gets named first (keeps name) If it is a transition metal it needs roman numeral Anion gets named second Add ide to the end of the anion name Polyatomic always keep their name. Ionic Bonds Easily Ionize in Water hortcut to Hydrolosis of alt.lnk Ions Increase Electrical Conductivity HYDROLOI OF WATER 4
Properties of Ionic Compounds ionic compound, such as rock salt (NaCl): 1. hard (doesn t dent) 2. rigid (doesn t bend) 3. brittle (cracks without deforming) Lattice Energy Lattice Energy is how much required to separate the ionic bonds. Water gives in energy (endothermic) and then reaction gives off energy (exothermic) Overall reaction is exothermic ANT DI IONIC BONDING Why are ionic solids brittle? trong repulsive forces IONIC LATTICE TRUCTURE Ionic lattices are extremely difficult structures to break apart. As a result, all ionic substances are solids with high melting points. Potassium iodide, magnesium chloride and calcium oxide. All of these ionic compounds have melting points over 500 C. There is one method of breaking up the lattice - dissolve the ionic compound in water. Water has the ability (polarity) to separate the ions from the lattice and allow them to move freely as a solution. (it poles them apart. JOD) TRONG in crystal IONIC BOND BROKEN in H 2 O 5
Ionic Bonds Are the Reaction of a Metal and a Nonmetal How Do We Tell The Difference? IONIC BOND DO NOT INCLUDE METALLOID The elements in the middle, metalloids, exhibit some metal-like behavior but also form covalent-like bonds. Hydrogen tends to behave more like a nonmetal in bonding except at high pressure at which it actually assumes a phase with the properties of a liquid metal. ince we don't deal with such high pressures normally, hydrogen is often just considered a nonmetal. Ionic bonding: Transfer of electrons Network of cations and anions Metals (left) with non-metals (right) Atoms achieve pseudo-noble configurations trong interactions due to large electrostatic forces (+/-) Lattice energy: quantitative description of binding energy in ionic compounds They (NaCl, MgO, ect.) are not molecules but lattice tructures Ionic compounds: odium Chloride NaCl odium gives away electron to become more stable. MgO Chlorine has 1 electron short of a stable noble gas structure, so it takes it. CaCl K 2 O 6
Magnesium Oxide MgO ionic bonding is stronger than NaCl Due to 2+ ions attracting ions. Greater charge = greater attraction Calcium Chloride Two chlorines to use up 2 electrons in the calcium. The formula of calcium chloride is therefore CaCl 2. Ionic Bonds (Lattice Energy) imilar to NaCl Potassium Oxide Two Potassium donate 2 electrons to one oxygen. The formula of calcium chloride is therefore K 2 O. Ionic Bonds (Lattice Energy) imilar to NaCl MP/BP is proportional to the lattice bond strength Higher bond strength = Higher Temperature Group 1A: Lose 1 electron to form 1+ ions H 1+ Li 1+ Na 1+ K 1+ Rb 1+ 7
Group 2A: Loses 2 electrons to form 2+ ions Be 2+ 2+ Mg 2+ Ca 2+ r 2+ Ba 2+ B 3+ Al 3+ Ga 3+ Group 3A: Loses 3 electrons to form 3+ ions Neither! Group 4A Group 4A: Lose 4 elements rarely form electrons or gain ions. 4 electrons? N 3- P 3- As 3- Nitride Phosphide Arsenide Group 5A: Gains 3 electrons to form 3- ions O e Oxide ulfide elenide Group 6A: Gains 2 electrons to form ions F Cl Fluoride Chloride Br Bromide Group 7A: Gains 1 electron to form I 1 - Iodide ions 8
Group 8A: table noble gases do not form ions! Formula of Ionic Compounds 2 x +3 = +6 3 x -2 = -6 Al 2 O 3 Al 3+ O ALUMINUM OXIDE 1 x +2 = +2 2 x -1 = -2 CaBr 2 Ca 2+ Br - CALCIUM BROMIDE +1 x 2 = +2 1 x -2 = -2 Na 2 Na + ODIUM ULFIDE 2.6 Aluminum Oxide Cesium ulfide Cobalt (II) Oxide Barium Chloride Boron ulfide Lithium elenide Write Formulas for these: Al 3+ Cs + Co 2+ Ba 2+ B 3+ Li + O O Cl - e Al 2 O 3 Cs 2 CoO BaCl2 B 2 3 Li 2 e Group B elements: Many transition elements have more than one possible oxidation state. Note the use of Roman Iron (II) = Fe 2+ numerals to show charges Iron (III) = Fe 3+ ome of the post-transition transition elements also have more than one possible oxidation state. Tin (II) = n 2+ Lead (II) = Pb 2+ Bismuth (II) =Bi 2+ Tin (IV)=n 4+ Lead (IV)= Pb 4+ Bismuth (V)=Bi 5+ Group B elements:ome transition elements have only one possible oxidation state, such as these three that are always: ilver = Ag 1+ Zinc = Zn 2+ Cadmium = Cd 2+ 9
Exceptions YOU HAVE TO MEMORIZE: ome of the transition metals have only one ionic charge: Do not use roman numerals for these : ilver is always 1+ (Ag 1+ ) Cadmium and Zinc are always 2+ (Cd 2+ and Zn 2+ ) Naming Ionic Compounds Binary Ionic Compounds implest Ionic compounds: Metal + Non-metal Polyatomic Ionic Compounds Writing formulas for binary ionic compounds. Formulas and Names of ome Polyatomic Ions NH + 4 ammonium CO 2 3 carbonate H 3 O + hydronium HCO 3 hydrogen carbonate (bicarbonate) OH hydroxide OCN cyanate CN cyanide CN thiocyanate O 2 peroxide 2 O 2 3 thiosulfate N 3- azide CrO 2 4 chromate NO 2 nitrite Cr 2 O 2 7 dichromate NO 3 nitrate O 2 4 sulfate ClO hypochlorite O 2 3 sulfite ClO 2 chlorite HO 4 hydrogen sulfate (bisulfate) ClO 3 chlorate PO 3 4 phosphate ClO 4 perchlorate HPO 2 4 monohydrogen phosphate MnO 4 permanganate H 2 PO 4 dihydrogen phosphate C 2 H 3 O 2 acetate (OAc-) HO 3 hydrogen sulfite (bisulfite) C 2 O 2 4 oxalate Classifying Compounds Is there a metal or a polyatomic ion present? If the answer is yes, use the system for naming ionic compounds. If the answer is no, use the system for naming covalent compounds. Naming Ionic Compounds Ionic compounds are named simply by naming the ions present. There are, however, two complicating factors: I. ome metals form more than one ion. II. Identifying polyatomic ions I. Metals that form more than one ion, such as iron, add a Roman numeral to the name to indicate the charge: Fe 2+ is called iron (II) and Fe 3+ is called iron (III) Assume a Roman numeral is required for any metal except 1. metals in groups IA and IIA on the periodic table 2. aluminum, cadmium, silver, and zinc 10
Naming cations We will use the tock system. Cation - if the charge is always the same (like in the Group 1&2 metals) just write name of the metal. Transition metals can have more than one type of charge. Indicate their charge with roman numerals in parenthesis after the name of the metal Practice by naming these: Na + Cd 2+ Ag + Fe 3+ Fe 2+ Pb 2+ Zn 2+ odium Ion Cadmium Ion ilver Ion Iron (III) Ion Iron (II) Ion Lead (II) Ion Zinc Ion Write Formulas for these: Potassium ion Magnesium ion Copper (II) ion Chromium (IV) ion Barium ion Mercury (II) ion K + Mg 2+ Cu 2+ Cr 4+ Ba 2+ Hg 2+ Naming Anions Anions are always the same charge Change the monatomic element ending to ide F - a Fluorine atom becomes a Fluoride ion. Practice by naming these: Cl - N 3- Br - O Chloride Ion Nitride Ion Bromide Ion Oxide Ion Write symbols for these: ulfide ion Iodide ion Phosphide ion elenide ion I - P 3- e 11
Write Formulas for these: Potassium Bromide K + Br - KBr Magnesium Nitride Mg 2+ N 3- Mg 3 N 2 Copper (II) Chloride Cu 2+ Cl - CuCl2 Naming Binary ionic compounds. Chromium (IV) Oxide Cr 4+ O CrO2 Barium ulfide Ba 2+ Ba Mercury(II) Fluoride Hg 2+ F - HgF2 Formula Reasoning Name FeCl 2 Fe2O3 Pb 2 Cu 3N Cl has a charge, and there are 2 of them for a total of, so the Fe must be 2+ O has a charge, and there are 3 of them for a total of 6-, so the Fe must have a total charge of 6+ split equally between the two iron atoms, so each must have a 3+ charge has a charge, and there are 2 of them for a total of 4-, so the Pb must be 4+ N has a 3- charge, so the Cu must have a total charge of 3+ split equally between the 3 copper atoms, so each must have a 1+ charge iron (II) chloride iron (III) oxide lead (IV) sulfide copper (I) nitride MONOATOMIC NAMING RACE 1) copper (II) chloride 2) sodium hydroxide 3) lithium oxide 4) cobalt (III) chloride 5) aluminum sulfide 6) francium bromide 7) iron (III) phosphide 8) vanadium (V) nitride 9) calcium iodide 10) manganese (III) fluoride CuCl 2 NaOH Li2O CoCl 3 Al 2 3 FrBr FeP CaI 2 MnF 3 QUETION ON BINARY IONIC BONDING Writing formulas for polyatomic ionic compounds. 12
Polyatomic ions are Groups of atoms that stay together and have an overall charge, and one name. Usually end in ate or -ite Acetate: C 2 H 3 O 2 Nitrate: NO 3 Nitrite: NO 2 Permanganate: MnO 4 Hydroxide: OH and Cyanide: CN? ulfate: O 4 ulfite: O 3 Carbonate: CO 3 Chromate: CrO 4 Dichromate: Cr 2 O 7 Phosphate: PO 4 3- Phosphite: PO 3 3- Ammonium: NH 4 1+ (One of the few positive polyatomic ions) If the polyatomic ion begins with H, then combine the word hydrogen with the other polyatomic ion present: H 1+ + CO 3 HCO 3 hydrogen + carbonate hydrogen carbonate ion prefix per- -orhypo Nomenclature of Polyatomic Oxy Anions suffix + Root identifies the element other than O (or H) + -ate -or- -ite contains 1 fewer O atoms than does the -ate ion -ate ions 3A 4A 5A 6A 7A CO 3 carbonate NO 3 nitrate PO 3-4 O 4 ClO 3 phosphate sulfate chlorate -ite ions Prefixes 3A 4A 5A 6A 7A CO 2 NO 2 carbonite nitrite per: contains 1 more O atom than the - ate ion PO 3 3- O 3 ClO 2 phosphite sulfite chlorite hypo: contains 1 fewer O atoms than the - ite ion 13
ClO 4 ClO 3 ClO 2 Prefixes per chlorate chlorate chlorite Writing Ionic Compound Formulas Barium nitrate ( ) Ba 2+ NO - 3 ClO hypo chlorite Now balanced. Not balanced! = Ba(NO 3 ) 2 Writing Ionic Compound Formulas Writing Ionic Compound Formulas Calcium sulfate formula? Aluminum phosphate Ca 2+ (O 4 ) Now balanced. Al 3+ (PO 4 ) 3- They ARE balanced! = AlPO 4 = Ca (O 4) topped here for CHEM 1 Naming Ionic Compounds w/ Polyatomic Ions A few of the more common polyatomic ions polyatomic cation polyatomic anion 1. magnesium sulfate MgO4 or polyatomic cation anion root + ide 2. ammonium chloride NH 4 Cl or cation polyatomic anion 3. ammonium sulfate (NH 4 ) 2 O 4 Formula C 2H 3O 2 CO 3 HCO 3 NH 1+ 4 NO 3 OH PO 3-4 O 4 Name acetate carbonate bicarbonate ammonium nitrate hydroxide phosphate sulfate C2H3O2 CO3 HCO 3 NH4 1+ NO 3 OH PO 4 3- O 4 acetate carbonate bicarbonate ammonium nitrate hydroxide phosphate sulfate * Groups I & II, Al, Zn, Cd, and Ag need no Roman numeral. 14
Na 2 O 4 sodium sulfate POLYATOMIC NAMING RACE Fe(NO 3 ) 2 AlCl 3 PbI 4 (NH 4 ) 3 PO 4 Mg 3 N 2 iron (II) nitrate aluminum chloride lead (IV) iodide ammonium phosphate magnesium nitride 1) beryllium nitrate 2) nickel (III) sulfite 3) potassium nitrite 4) zinc phosphate 5) aluminum sulfate 6) francium hydroxide 7) iron (III) phosphite 8) bismuth (V) phosphate 9) calcium permanganate 10) manganese (III) hypochlorite Be(NO 3 ) 2 Ni 2 (O 3 ) 3 K NO 2 Zn 3 (PO 4 ) 2 Al 2 (O 4 ) 3 FrOH Fe(PO 3 ) (Bi) 3 (PO 4 ) 5 Ca(MnO 4 ) 2 AgC 2 H 3 O 2 silver acetate scandium hydroxide POLYATOMIC NAMING RACE 1) sodium nitrite 2) scandium (III) hydroxide 3) vanadium (III) sulfate 4) ammonium fluoride 5) calcium carbonate 6) nickel (III) phosphate 7) lithium sulfite 8) zinc phosphate 9) strontium acetate 10) copper (I) oxide Na (NO 2 ) V 2 (O 4 ) 3 NH 4 F CaCO 3 NiPO 4 Li 2 O 3 Zn 3 (PO 4 ) 3 r(c 2 H 3 O 2 ) 2 Cu 2 O 1. Ag 3 PO 4 2. YClO 3 3. n 2 4. Ti(CN) 4 5. KMnO4 6. Pb 3 N 2 7. CoCO 3 8. CdO 3 9. Cu(NO 2 ) 2 10. Fe(HCO 3 ) 2 POLYATOMIC NAMING RACE silver phosphate Yttrium (I) chlorate tin (IV) sulfide titanium (IV) cyanide potassium permanganate lead (II) nitride cobalt (II) carbonate cadmium sulfite copper (II) nitrite iron (II) bicarbonate CuC 2 H 2 O 2 NaHCO 3 CaCO 3 LiH 2 PO 4 Copper (I) Acetate odium Hydrogen Carbonate (Bicarbonate) Calcium Carbonate Lithium Dihydrogen phosphate Cobalt (II) Cyanide Iron (III) Oxide Ammonium Nitrate Iron (II) Phosphite Co(CN) 3 Fe 2 O 3 CaCO 3 Fe 3 (PO 3 ) 2 (NH 4 ) 3 PO 4 ammonium phosphate Potassium Acetate KC 2 H 2 O 2 Mg 3 N 2 magnesium nitride Zinc Phosphate Zn 3 (PO 4 ) 2 AgC 2 H 3 O 2 silver acetate silver acetate AgC 2 H 3 O 2 15
Naming s What the book doesn t teach, yet is essential for future success in Chem: acid: Any compound with Hydrogen as a cation: HX (or HA if you like) H+ = hydrogen ion, X = any negative ion Naming is determined by the original name of X (anion) If X- ends in -ide --- acid name becomes Hydro-X-icacid HCl Hydrochloric HBr Hydrobromic HF HydroFlouric 2. if X- ends in -ate --- acid name becomes X-ic acid ( No Hydro-) HNO3 Nitric H 2 O 4 ulfuric HClO 3 Chloric 3. if X- ends in -ite --- acid name becomes X-ous acid HNO 2 Nitrous H 2 O 3 ulfurous HCl0 2 Chlorous POLYATOMIC NAMING RACE 11)H 3 PO 4 12)HClO 2 12)HNO 2 13)HC 2 H 3 O 2 15)H 3 PO 3 16)H 2 CrO 4 17)HCO 3 18) H 2 19) HNO 3 20) HI Phosphoric Chlorous Nitrous Acetic Phosphorous Chromic Carbonic Hydrosulfic Nitric Hydroiotic 16