ALEVEL化学.ppt

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1、 On the Periodic Table remember where to:and the find the Ionic Compounds There are two types of ionic compounds1. Binary ionic compounds and2. Ionic compounds that contain “polyatomic ions”.Type 1: Binary Ionic Compounds1. “Binary” means as in “bicycle” “2 wheels”) A binary ionic compound has only

2、: (example: BaCl2)1.The element is always a 2.The element is always a Type 1: Binary Ionic Compounds “2 elements” means just that “2 elements”!There be more than one ion of an element! Example: AlF3 AlF3 contains only 2 elements: Al & F. AlF3 has 1 Al+3 ion, and 3 F-1 ions. metal (+) & nonmetal (-)T

3、he subscript tells you how many ions are in the compound (a “1” is understood and not written)Naming Binary Ionic Compounds To name a binary ionic compound1. Write the name of the metal ion (+)(this is just the name of the metal)2. Write the name of the nonmetal ion (-)(the nonmetal ion has the same

4、 “root” as the nonmetal, but with an “-ide” ending)”).Examples: “chlorine” becomes “chloride” “oxygen” becomes “oxide” “nitrogen” becomes“nitride”Thats It!Just write the metal ion name first, then the nonmetal ion name second! (remember the “ide” nonmetal ending)Practice: (name these)K2SMgOSr3As2pot

5、assium sulfidemagnesium oxidestrontium arsenide Remember, metals are always (+) because they electrons, and Nonmetals are always (-) because they electrons!Writing Binary Ionic Compounds To a binary ionic compound formula you must know the of the metal ion and the nonmetal ion! There are two ways to

6、 know these them, or Look at the You Guessed it!The “representative” elements are +1+2+3Each family has its own charge!-3 -2 -10Noble gas “wannabes”, remember?In Family 14, only Sn and Pb form ions14 The transition metals do not follow any simple rules. (Many have two possible charges!) Some must be

7、 memorized, but, there IS an easy system for the others Examples: “copper(I)” = Cu+1 “iron(III)” = Fe+3 “lead(IV)” = Pb+4There will be four metals we will study that have two different “oxidation numbers”, or charges(there are others!)Iron (Fe), Copper (Cu), Lead (Pb) and Tin (Sn)1.Iron: Fe+2 iron (

8、II), or Fe+3 iron (III)2.Copper: Cu+1 copper (I), or Cu+2 copper (II)3.Lead: Pb+2 lead (II), or Pb+4 lead (IV)4.Tin: Sn+2 tin (II), or Sn+4 tin (IV) Be sure the (+) charges = the (-) charges! Example: “aluminum fluoride”aluminum ions are Al+3fluoride ions are F-1Al+3F-1AlF3(Al+3 + F-1 + F-1 + F-1)Ad

9、ds up to zero!The compound hasNO charge!Practice: write the formula for:Writing Binary Ionic Compoundscalcium fluoridelithium phosphidealuminum oxide+2-1CaF2+3Al2O3+1-3Li3P-2copper(II) chlorideCuCl2Cu+2and Cl-1Ionic formulas are “formula units” of ionic compounds ionic compounds form molecules!Remem

10、ber to reduce any ionic formula to a lowest ratio Example: barium oxideBa+2O-2Ba2O2?Reduce to “BaO”Special Note: be to write element symbols clearly! Lower and upper case letters be obvious!Type 2: Ionic CompoundsContaining “Polyatomic Ions”Polyatomic ions are !(most will have a negative (-) charge,

11、 just like a non-metal ion)You will be given a list of these to useO “poly” means “many”, so “polyatomic” means “many atoms”! (These are ions made of of atoms)!Polyatomic IonsAn example: the polyatomic ion, “nitrate”NOO-1This group of atoms carries a charge of (-1).contains 1 nitrogen and 3 oxygen a

12、toms!Naming Ionic Compounds With Polyatomic IonsTo name an ionic compound with polyatomic ions is really EASY1.Write the name of the positive ion (+)(usually the name of the metal, but watch for Fe, Cu, Sn, and Pb Roman Numerals needed)2.Write the name of the negative ion (-)(usually the polyatomic

13、ion) Example: Mg(NO3)2“magnesium nitrate”Practice naming ionic compounds containing polyatomic ions (get out your ion list)(NH4)2CO3K3PO4Zn(MnO4)2CuClO3Pb(OH)2Ammonium carbonatePotassium phosphateZinc permanganateCopper (I) chlorateLead (II) hydroxide To a formula using polyatomic ions,you must know

14、 the and of the metal ion and the polyatomic ion. The metal ions you know (periodic table)you will get with their formulas and charges. Just look at the charges, and make sure they add up to zero.“sodium” = Na+1“carbonate” = CO3-2Na+1CO3-2+ Na+1Na+1+ CO3-2Adds up to zero!Example: “sodium carbonate”

15、Wrap the polyatomic ion in , then add the subscript. Example: “aluminum sulfate”aluminum ions are Al+3sulfate ions are SO4-2Al+3SO4-2(Al+3 + Al+3 +Adds up to zero!SO4-2 + SO4-2 + SO4-2)2 Al+33 SO4-2Practice writing the formula of ionic compounds containing polyatomic insNH4IAl(CN)3Sn(NO3)2Zn3(PO4)2P

16、b(SO4)2Ammonium iodideAluminum cyanideTin (II) nitrateZinc phosphateLead (IV) sulfateHYDRATESSome ionic compounds “collect” water from the moisture in the air.They trap this “collected water” in their crystals.When they have trapped this water, they are called “hydrates”. Their formula includes water, written after a raised dot: MgSO4 5H20(magnesium sulfate pentahydrate)PrefixMonoDiTriTetraPentaHexaHeptaOctaNonaDecaNumber of H20s12345678910Note: these prefixes will also be used when naming coval