Ionic Compounds and Metals

Ionic Compounds and MetalsChemistry Matter and Change: Chapter 7BIG IDEAAtoms in ionic compounds are held together by chemical bonds formed by the attraction of oppositely charged ions. 7.1 Ion Formation

7.1 Main IdeaIons are formed when atoms gain or lose valence electrons to achieve a stable octet electron configuration.7.1 ObjectivesDefine a chemical bond.Describe the formation of positive and negative ionsRelate ion formation to electron configuration.Review Vocabulary & ConceptsIonValence electronOctetElectron configurationLewis-dot diagramsElectron affinity

New VocabularyChemical bondIonic bondCationAnionChemical BondThe force that holds two atoms togetherThree types Ionic bonds *Chap 7Metallic bonds *Chap 7Covalent bonds *Chap 8Valence Electrons and Chemical Bonds Each valence electron is represented as a dot around the nuclear core of the element.

Valence Electrons and Chemical BondsThe most stable electron configuration for an element is the nearest noble gas.ns2np6Octet Ions gain or lose electrons to achieve noble gas configurationsOctet RuleFormation of Ions

Positive Ion FormationCation: a positively charged ionResults when electrons are lost

Metal ionsGroup 1 loses 1 electron+1 chargeGroup 2 loses 2 electrons+2 chargeGroup 13 loses 3 electrons+3 charge Groups 3-12 usually lose 2 electronsMost have +2 charge (range from +1 to +3)Negative Ion FormationAnion: negatively charged ionFormed when electrons are gainedNon-metals

Nonmetal Ions Group 15 gains 3 electrons3- chargeGroup 16 gains 2 electrons2- chargeGroup 17 gains 1 electron1- charge

Section SummaryA chemical bond is the force that holds two atoms togetherSome atoms gain or lose electrons to gain a stable configuration; these are called ionsMost stable configurations end: ns2np6.

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SodiumElectron loss or ionization of sodium atom Na 1s22s22p63s1 Na+ 1s22s22p6

The electron configuration of a sodium ion is the same as a neon atom

ChlorineA gain of one electron gives chlorine an octet and converts a chlorine atom into a chloride ion.

It has the same electron configuration as argon

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Gain of valence electrons2121Section 7.1 practice #1:1. How many valence electrons does each of the following atoms have?gallium fluorine seleniumSection 7.1 practice #2:2. For each element below, state (i) the number of valence electrons in the atom, (ii) the electron dot structure, and (iii) the chemical symbol(s) for the most stable ion.Ba I KSection 7.1 practice #33. Write the electron configuration for each of the following atoms and ions.K atomK ionc. Na atomd. Na ion e. Phosphorous atomf. Phosphide ion Section 7.1 practice #44. How many electrons will each element gain or lose in forming an ion? State whether the resulting ion is a cation or an anion.a. strontium (Sr)b. tellurium (Te)c. Bromine (Br)d. aluminum (Al)e. rubidium (Rb)f. Phosphorus (P)7.2 Ionic Bonds and Ionic Compounds7.2 Main IdeaOppositely charged ions attract each other forming electrically neutral ionic compounds.7.2 ObjectivesDescribe the formation of ionic bonds and the structure of ionic compoundsGeneralize about the strength of ionic bonds based on the physical properties of ionic bondsCategorize ionic bond formation as exothermic or endothermic Review Vocabulary & ConceptsCompoundChemical bondPhysical propertyChemical propertyElectronegativity New VocabularyIonic bondIonic compoundCrystal latticeBinary compoundElectrolyte Formation of an Ionic BondElectrons are exchanged between atomsIncreases stability of bothIons are held together by the opposite charges

Definition of Ionic Bond Bond formed between two elements with an electronegativity difference > 1.7Crystallize as sharply defined particles

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Binary Ionic Compounds Formed from a metal and a non-metalContain only two elementsExamplesNaClMgOCaCl2Fe2O3Formation of Ionic CompoundsNet charge on all ions in a compound must be zero (0)!More on this later!!!

Properties of Ionic CompoundsCrystal Lattice: Highly organized crystal of cations and anions

AnionCation

Properties of Ionic Compounds Crystalline shape depends on the ions involved

Properties of Ionic CompoundsPhysical propertiesVery strongSolid at normal temperaturesVery high melting point and boiling pointMany have brilliant colors due to transition metalsHard, rigidBrittle

Properties of Ionic CompoundsConductivity (ability for electric charge to move through a substanceSolids have electrons locked in placeNon conductiveAqueous solutions have easily moveable electronsElectrolytesGood conductors

Properties of Ionic CompoundsDissolve in waterMay have radically different properties than the elements that compose them

Polar Dissolution

Water and ionic bondsProperties of Ionic CompoundsFormation of lattice is always exothermic.

Section SummaryIonic compounds contain ionic bonds formed by the attraction of oppositely charged ions.Ions in an ionic compound are arranged in a repeating pattern called a lattice.Ionic compounds are electrolytes; they conduct electricity in liquid and aqueous states.

Can youDescribe the formation of ionic bonds and the structure of ionic compoundsGeneralize about the strength of ionic bonds based on the physical properties of ionic bondsCategorize ionic bond formation as exothermic or endothermic

7.3 Names and Formulas for Ionic Compounds7.3 Big IdeaIn written names and formulas for ionic compounds, the cation appears first, followed by the anion.7.3 ObjectivesRelate a formula unit of an ionic compound to its compositionWrite formulas for ionic compounds and oxyanions.Apply naming conventions to ionic compounds and oxyanions.Review Vocabulary & ConceptsAnionCationMetalNon-metal

New VocabularyFormula unitMonatomic ionPolyatomic ionOxidation numberOxyanion

Describing Ionic CompoundsFormula unit- simplest way to indicate the composition of an ionic substanceNaClMgCl2

Cl-Cl-Mg2+Monatomic Ions Ions in which only one element is presentNa+, Cl-, Mg2+, P3-

Oxidation numberFancy word for chargeaka oxidation stateTransition metals may have multiple oxidation states Must tell the oxidation state Ex: Iron 2+ is Iron II; Iron 3+ is Iron IIIFormulas for Binary Ionic CompoundsCxAyC is cationA is anionx number of cations in one unity is number of anions in one unitRules for writing formula units CxAyCation is always firstAnion is always secondNet oxidation MUST BE ZERO

Tried and True MethodWrite out each ion.Place oxidation number under each ionCross multiplyReduce to simplest form

Write out each ion.Example 1: Sodium and chlorineNaClPlace oxidation number under each ionSodium and chlorineNaCl+1-1Cross multiplySodium and chlorineNaCl+1-1

Na Cl1 1Reduce to simplest formRemove any 1sNaClReduce if neededNaClWrite out each ion.Iron III and oxygen

FeOPlace oxidation number under each ionExample 2:Iron III and oxygen

FeO3+2-Cross multiplyIron III and oxygen

FeO3+2-2 3Fe OReduce to simplest formFe2O3Cannot be reducedWrite out each ion.Example 3:Magnesium and oxygen

MgOPlace oxidation number under each ionMagnesium and oxygen

MgO2+2-Cross multiplyMagnesium and oxygen

MgO 2+2-2 2Mg OReduce to simplest formMg2O2Both subscripts can be divided by 2 so the final formula is

MgOPracticeSilver I and chlorineAntimony (V) oxideAluminum sulfideMagnesium and fluorineIron II and oxygenCalcium and phosphorusWhy did we specify some oxidation numbers, but not others?Rules for Naming Binary Ionic CompoundsState the name of the cation. (If using a transition metal, you must state the oxidation number if there is more than one possibility.)State the name of the anion, but change the ending to ide.

PracticeNaClSodium chlorine chlorideMgOMagnesium oxideK2SPotassium sulfideTricky practiceFe2O3Iron is a transition metal so we need to figure out the charge before we can name the compound.We know oxygen is always -2, so there is an overall charge of -6 from the oxygenThat means Iron must supply an overall charge of +6This indicates that iron must have an oxidation number of +3 in this caseTricky practiceFe2O3Iron III oxideCuSAgCl* (trick!)H2O

Monatomic Ions vs polyatomic IonsMonatomic ion: a one atom ionEx. Mg 2+

Polyatomic ion: ions made up of more than atomEx. PO4 3-

OxyanionsOxyanions- a polyatomic ion composed of an element, usually a nonmetal, bonded to one or more oxygen atoms.

The ion with the greater number of oxygen atoms ends in ate. The ion with the fewer number of oxygen atoms ends in ite.Ex. NO3- NO2-NitrateNitrite Take out a sheet of paperDirections: Draw 5 by 5 chart. Write 5 metals ions in the left marginWrite 5 nonmetal ions on the topTrade charts with the person next to youFill in the charts by writing the correct formulas for the ionic compounds formed in the square.Hand the chart back to your partner when your done and check each others responses.Once finished, raise your hand and ask Mrs. Chebib to come over and stamp your work for credit

Naming Polyatomic Ions State the name of the cation. (If using a transition metal, you must state the oxidation number if there is more than one possibility.)Name the anion PracticeAgNO3Silver nitrateCaCO3Calcium carbonateNH4ClAmmonium chlorideFeSO4Iron II sulfateWriting formulas for ionic compounds with polyatomic ions Write out each ion.Place oxidation number under each ionCross multiplyReduce to simplest form

Side noteOxyanions are any polyatomic anions that contain oxygenYour book likes to sound fancy!Writing formulas for ionic compounds with polyatomic ions You may not, under any conditions, change the subscripts within the polyatomic ion when balancing the charge. You may only adjust the number of units of each polyatomic ion!!Use parentheses to remind yourself that the units go together and cannot be changed.Write out each ion.Potassium permanganate K(MnO4)Place oxidation number under each ionPotassium permanganate K(MnO4)+1-1Cross multiplyPotassium permanganate K(MnO4)+1-1

1 1K (MnO4)Reduce to simplest formPotassium permanganate is K(MnO4)Write out each ion.Calcium hydroxideCa(OH)Place oxidation number under each ionCalcium hydroxideCa(OH)+2 -1Cross multiplyCalcium hydroxideCa(OH)+2-1

Ca(OH)2Reduce to simplest formCa(OH)2Write out each ion.Ammonium phosphate(NH4)(PO4)Place oxidation number under each ionAmmonium phosphate(NH4)(PO4) +1 -3

Cross multiplyAmmonium phosphate(NH4)(PO4) +1 -3(NH4)3(PO4)

Reduce to simplest form(NH4)3(PO4)PracticeSodium nitrite Calcium sulfateAluminum hydroxide

Section SummaryA formula unit gives the ration of cations to anions in the ionic compound.A monatomic ion is formed from one atom.Roman numerals indicate the oxidation numbers of any element with more than one oxidation number.Section SummaryPolyatomic ions consist of more than one atom and act as a single unit.To indicate more than one polyatomic ion in a chemical formula, place parentheses around the polyatomic ion and use a subscript outside the parentheses.Can youRelate a formula unit of an ionic compound to its compositionWrite formulas for ionic compounds and oxyanions.Apply naming conventions to ionic compounds and oxyanions.7.4 Metallic Bonds and the Properties of Metals7.4 Main IdeaMetals form crystal lattices and can be modeled as cations surrounded by a sea of freely moving valence electrons. 7.4Describe a metallic bondRelate the electron sea model the physical properties of metalsDefine alloys and categorize them into two basic types.Review Vocabulary & ConceptsPhysical propertyMetalMalleable

New VocabularyElectron sea modelDelocalized electronMetallic bondAlloy

Metallic BondsLattice structures with freely moving electronsElectrons are not firmly attached to any one nucleus, but instead visit many nuclei

Metallic BondsAttraction of a metallic cation for delocalized electrons

The Electron SeaFreely moving electrons are referred to as delocalized (lacking a location)

Video++++++++++++++++++++++++++++++-----------------------------Properties of MetalsMelting and Boiling pointsVary greatlyMost are moderately high melting points and very high boiling points

Properties of MetalsMalleability, ductility and durabilityNuclei move relatively free of each other due to the sea of electrons

Properties of MetalsThermal and electrical conductivity Delocalized electrons quickly move heat from one part of the metal to other partsDelocalized electrons can move in one direction and create a current.Properties of MetalsHardness and strengthThe number of delocalized electrons plays a role in the hardness of the metalMore delocalized electrons means a harder metalSometimes d level electrons are delocalized as well as the s resulting in very hard metals.Metal AlloysAlloy- a mixture of elements that has metallic propertiesCharacteristics may differ from the parent metalsInclude brass, bronze, 14-carat gold, stainless steel, etc.Types of Metal AlloysSubstitutionalSome of the atoms from one metal are replaced by atoms of the other metalEx: brass

Types of Metal AlloysInterstitialSmall holes in the lattice are filled by atoms of another elementExample: Steel

Section SummaryA metallic bond forms when metal cations attract freely moving, delocalized valence electrons.The electron sea model explains the physical properties of metallic solids.Metal alloys are formed when a metal is mixed with one or more other elements.Can youDescribe a metallic bondRelate the electron sea model the physical properties of metalsDefine alloys and categorize them into two basic types.