1Polyatomic ions & Naming ionic Compounds Unit 5: Chapter 6.3a
2Bonding Review Ionic - electron transfer Forms between a metal and a nonmetalMetals have low electronegativityNonmetals have high electronegativityThe metal gives up the electrons and the nonmetal takes themCovalent - electron sharingForms most often between two nonmetalsElectron shared pairs are formed to allow both elements to fulfill the octet rule.
3Describing Ionic Compounds These objects are coated with compounds of copper and oxygen. Based on the two colors of the coatings, copper and oxygen must form at least two compounds. So there must also be different ways of naming them.
4Describing Ionic Compounds What information do the name and formula of an ionic compound provide?The name distinguishes the compound from other ionic compounds containing the same elements.The formula of an ionic compound describes the ratio of the ions in the compound.
5Binary Ionic Compounds A compound made from only two elements is a binary compound.Naming binary ionic compounds is easy. The names have a predictable pattern:the name of the cation (metal) followed by the name of the anion (nonmetal).Examples:Na+ + Cl- Sodium Ion + Chloride =Sodium ChlorideK+ + O2- Potassium Ion + Oxide =Potassium Oxide
6Common Anions This table lists eight common anions. The name of an anion is formed by adding the suffix –ide to the stem of the nonmetal name.
7Naming Binary Ionic Compounds Cations (metal) first, then Anion (non-metal)Cation (metal) name is normalExample: sodiumAnion (nonmetal) add “ide” suffixExample: chlorine chlorideNaCl sodium chlorideKBr potassium bromide
8Polyvalent Metals Many transition metals have “multiple personalities” # of valence electrons variesthey can form more than one ion (more than one charge).Also known as valence # or oxidation #Roman Numerals are used to signify the charge (or how many electrons the metal is lending)Where are the transition metals located on the periodic table?
10Polyvalent Transition Metals Metals with more than one possible charge:Specific charge is indicated in parenthesis
11Polyvalent Metals & Bonding Fe(II) = Fe2+Iron (II) + oxygen = Iron (II) OxideFe2+ & O2- FeOFe(III) = Fe3+Iron (III) + oxygen = Iron (III) OxideFe3+ & O2- Fe2O3Name these compounds just like other binary ionic compounds but include the metal’s oxidation # in parentheses
12Polyatomic IonsPolyatomic Ion - A covalently bonded group of atoms that acts as a unit and has its own charge.Most simple polyatomic ions are anions.MUST keep the atoms togetherCANNOT change anything about a polyatomic ionNot the type of atomsNot the number of atomsNot the electric chargeHow are you going to remember this????Anytime you see a Polyatomic IonPUT IT IN PARENTHESIS!!!
14Polyatomic Ions & Bonding Bonding works the same way as it did for binary compounds.Treat the polyatomic ion as a single entity (a single element)The criss cross method is the most useful, efficient, and effective way for bonding with polyatomic ions.
15Criss Cross Method Review Determine the charges/oxidation #’s for each element.By criss crossing the charges of the elements you can easily write the chemical formulaExample: Hydrogen + OxygenH O–2Criss cross the oxidation #just the numbers - not the + / - signsWrite the numbers as subscriptsbottom right of symbol
16Criss Cross Method Review Criss Cross the numbersH2O1Final: H2OWhere is the 1 in the final formula?Just like in math, the 1 is always understood.
17Criss Cross & Polyatomic Ions Sodium + SulfateNa + SO4Na+1 + (SO4)-2Do the Criss CrossNa2(SO4)1Final: Na2(SO4) or Na2SO4
23You Try Beryllium + Phosphate Be + PO4 Be+2 + (PO4)-3 Criss Cross Note that the criss cross puts the subscript 2 OUTSIDE of the parenthesis, showing that there are TWO phosphate ions
24Common Ions Which of these are: Metals? Nonmetals? Transition metals? Hydrogen H+1Aluminum Al+3Nitrate (NO3)-1Calcium Ca+2Iron (III) Fe+3Sulfate (SO4)-2Zinc Zn+2Chlorine Cl-1Carbonate (CO3)-2Copper (II) Cu+2Hydroxide OH-1Phosphate (PO4)-3Silver Ag+1Phosphide P-3Acetate (C2H3O2)-1Which of these are:Metals?Nonmetals?Transition metals?Polyatomic ions?
25Naming with Polyatomic Ions Compounds containing polyatomic Ions always have IONIC bonds.Naming these compounds is much like naming binary ionic compoundsList the cation (metal) firstThen the polyatomic ion (most are anions so this follows the binary format)Use the normal name for the cation (metal) and the given name for the polyatomic ionNa(OH) or NaOH = Sodium Hydroxide
26Formulas & Names Use a compound’s formula to determine its name Na2O Sodium OxideCuF2 Copper (II) FluorideK2(CO3) Potassium CarbonateUse a compound’s name to determine its formulaLithium Bromide LiBrIron (III) Oxide Fe2O3Aluminum Phosphate Al(PO4) or AlPO4You must be able to go back and forth!
27You Try Write the formula for Calcium Chloride Calcium Oxide Copper (II) NitrideMagnesium SulfateGive the name for the following compoundsKBrBeSPbO2CsMnO4
28You Try Write the formula for Calcium Chloride CaCl2 Calcium Oxide CaOCopper (II) Nitride Cu3N2Magnesium Sulfate MgSO4Give the name for the following compoundsKBr Potassium BromideBeS Beryllium SulfidePbO2 Lead (IV) OxideCsMnO4 Cesium Permanganate