9-1 NAMING IONS DAY 3! CLOSED NOTES HANDOUT! MAIN IDEAS YOU COMPLETE! Objective Apply the rules for naming & writing formulas for Binary Compounds & polyatomic ionic compounds. IaN PG. 5 Key Concepts: You complete! Robert Orben

N AMING & WRITING FORMULAS FOR IONIC COMPOUNDS Day 3

W HAT ABOUT WHEN A TRANSITION METAL IS INVOLVED IN FORMING AN IONIC COMPOUND ??? Ex. What should we call CuO? Copper oxide is not correct because copper can form 2 different cations: Cu + = copper(I) ion Cu 2+ = copper(II) ion

To determine which ion was used in the compound, work backwards… Cu ? O 2- CuO The atoms are combining in a 1:1 ratio. O has a 2- charge, so Cu must be 2+ The name is copper(II) oxide

N AME THE FOLLOWING … SnF 2 Sn 2+ or Sn 4+ combining with F - Sn ? F - SnF 2 The F has a subscript of 2, so has to be tin(II) Two names are possible… Tin(II) fluoride (stock system) Stannous fluoride (classical system)

N AME THE FOLLOWING … SnS 2 Sn 2+ or Sn 4+ combining with S Sn ? S 2- SnS 2 If the compound contained Sn 2+ both subscripts in the compound would be 2 and they would be combining in a 1:1 ratio. In this case, the formula would be SnS. The compound has to be using Sn 4+ that would create Sn 2 S 4 which can be reduced to SnS 2. There are 2 possible names… Tin(IV) sulfide (stock system) Stannic sulfide (classical system)

N OW TRY NAMING THESE IONIC COMPOUNDS … FeS FeSO 4 FeSO 3 Cu(OH) 2 Sn(CO 3 ) 2

W RITING FORMULAS FOR BINARY IONIC COMPOUNDS If you know the name of a compound, you can write its formula… Ex. Potassium chloride K + Cl - KCl **Remember to always write the cation first. Ex. Calcium bromide Ca 2+ Br - CaBr 2

W RITE FORMULAS FOR THE FOLLOWING … Iron (III) oxide Calcium sulfide

Remember that an ending of –ite or –ate indicates the compound contains a polyatomic ion that includes oxygen. Ex. Calcium carbonate Ca 2+ CO 3 2- Ca 2 (CO 3 ) 2 The calcium and carbonate ions are combining in a 1:1 ratio, so simplify: CaCO 3 C OMPOUNDS WITH POLYATOMIC IONS

M ORE COMPOUNDS WITH POLYATOMIC IONS … Lead(II) sulfate Pb 2+ SO 4 2- Pb 2 (SO 4 ) 2 Again, the ions are combining in a 1:1 ratio, so simplify to: PbSO 4 Potassium hydrogen phosphate Potassium sulfate Sodium nitrate Calcium nitrate Lithium carbonate