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IONIC COMPOUNDS. Naming and Formula Writing. OBJECTIVES: Apply the rules for naming and writing formulas for binary ionic compounds. Apply the rules for naming and writing formulas for compounds containing polyatomic ions. Predicting Charges on Monatomic Ions KNOW THESE !!!!.
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IONIC COMPOUNDS Naming and Formula Writing
OBJECTIVES: • Apply the rules for naming and writing formulas for binary ionic compounds. • Apply the rules for naming and writing formulas for compounds containing polyatomic ions.
Predicting Charges on Monatomic Ions KNOW THESE !!!! +1 +2 -3 -2 -1 0 Cd+2
Naming Positive Ions • Before you name an Ion you have to know the charge. • Group 1 = always +1 • Group 2 = always +2 • Aluminum = always +3 • Zinc and Cadmium = always +2 • Silver = always +1
The Other Metals • All other metals can have various positive charges from +1 to +7 • Roman Numerals are used to tell the charge
Naming Postive Ions • With group 1, 2, Al, Zn, Cd, and Ag you just give the name of the atom • Na+ is Sodium • Mg+2 is Magnesium • Ag+ is Silver • Al+3 is Aluminum
All the other metals • With all other metals you give the name Metal followed by a roman numeral • Cu+ - Copper (I) • Cu+2 – Copper (II) • Fe+2 – Iron (II) • Fe+3 – Iron (III) • U+6 – Uranium (VI)
Naming negative ions • All negative ions have their endings changed to –ide • Oxygen becomes oxide • Fluorine becomes Fluoride • Nitrogen becomes Nitride • Chlorine becomes Chloride
Names of other Negative Ions • Carbide = what you want your parents to do for you • Boride = what happened at the rodeo • Silicide = what you are seeing right now • Fluoride = a state in the union • Iodide = Very sad, I guess we will have to Barium. • Telleride = Telling the driver where you want to go
Formulas of Ionic Compounds Formulas of ionic compounds are determined from the charges on the ions atoms ions – Na + F : Na+ : F : NaF sodium + fluorine sodium fluoride formula Charge balance: 1+1- = 0
Writing a Formula Write the formula for the ionic compound that will form between Ba2+ and Cl. To cancel out Ba’s +2, then two -1 Cl’s are needed. Solution: 1. Balance charge with + and – ions 2. Write the positive ion of metal first, and the negative ion Ba2+ ClCl 3. Write the number of ions needed as subscriptsBaCl2
Balancing a formula by math • Every ionic compound should have a formula that has a charge that equals zero. • Barium Fluoride • Ba+2 F- • How many F’s are needed to balance Ba+2 ? • Two • Formula is BaF2
Another way – Drop, Swap, Reduce • Aluminum Oxide • Al is always +3 • Oxide is always -2 • Al+3, O-2 • DROP: Al3O2 • SWAP: Al2O3 • REDUCE: 2 and 3 are lowest integers, so leave alone
Another example • Magnesium Oxide • Mg is +2 • Oxide is -2 • Mg+2, O-2 • DROP: Mg2O2 • SWAP: Mg2O2 • REDUCE: MgO, 2 and 2 divide each other out.
Writing Formulas from Names of Compounds • Calcium chloride • Calcium will form Ca2+ • Chlorine will form Cl1- • Formula is CaCl2 • Barium phosphide • Barium will form Ba2+ • Phosphorus will form P3- • Formula is Ba3P2 • Sodium sulfide • Sodium will form Na+ • Sulfur will form S2- • Formula is Na2S
Complete in your journal Learning Check Write the correct formula for the compounds containing the following ions: 1. Na+, S2- a) NaS b) Na2S c) NaS2 2. Al3+, Cl- a) AlCl3 b) AlCl c) Al3Cl 3. Mg2+, N3- a) MgN b) Mg2N3 c) Mg3N2
Naming Compounds Binary Ionic Compounds: • 1. Cation first, then anion • 2. Monatomic cation = name of the element • Ca2+ = calciumion • 3. Monatomic anion = root + -ide • Cl- = chloride • CaCl2 = calcium chloride
Examples: NaCl ZnI2 Al2O3 sodium chloride zinc iodide aluminum oxide Naming Binary Ionic Compounds
Complete in your journal Learning Check Complete the names of the following binary compounds: Na3N sodium ________________ KBr potassium ________________ Al2O3 aluminum ________________ MgS _________________________
Transition Metals Elements that can have more than one possible charge MUST have a Roman Numeral to indicate the charge on the individual ion. 1+ or 2+ 2+ or 3+ Cu+,Cu2+ Fe2+, Fe3+ copper(I) ion iron(II) ion copper (II) ion iron(III) ion
Names of Variable Ions These elements REQUIRE Roman Numerals because they can have more than one possible charge: anything except Group 1A, 2A, Ag, Zn, Cd, and Al (You should already know the charges on these!) Or another way to say it is: Transition metals and themetalsin groups 4A and 5A (except Ag, Zn, Cd, and Al) require a Roman Numeral. FeCl3(Fe3+) iron (III) chloride CuCl (Cu+ ) copper (I) chloride SnF4 (Sn4+) tin (IV) fluoride PbCl2 (Pb2+) lead (II) chloride Fe2S3 (Fe3+) iron (III) sulfide
Examples of Older Names of Cations formed from Transition Metals(you do not have to memorize these)
Complete in your journal Learning Check Complete the names of the following binary compounds with variable metal ions: FeBr2 iron (_____) bromide CuCl copper (_____) chloride SnO2 ___(_____ ) ______________ Fe2O3 ________________________ Hg2S ________________________
Polyatomic Ions • Some ions are composed of more then one atom. • These are called polyatomic ions • Poly = more
Formulas and names • Nitrate = NO3- • Sulfate = SO4-2 • Silver nitrate • Ag+ NO3- • DSR = AgNO3 • Copper (I) Sulfate • Cu+ SO4-2 • Cu2SO4
More Polyatomics • Lead (IV) Phosphate • Pb+4 PO4-3 • Pb3(PO4)4 • Notice: When more then one Polyatomic is present you surround it with () • Big: The subscripts on Polyatomic ions are NEVER changed.
Complete in your journal Learning Check Write the correct formula for the compounds containing the following ions: 1. Na+, PO4-3 a) NaPO4 b) Na2PO4 c) Na3PO4 2. Al3+, NO3- a) Al(NO3)3 b) AlNO3 c) Al3NO3 3. NH4+, N3- a) NH4N b) NH4N c) (NH4)3N
More on Polyatomics • Most polyatomic ions end in –ate. • The ending –ite means one less oxygen is present then in the ending –ate. • Example: Nitrate versus Nitrite: • NO3- NO2- • NOTICE: Only the number of O’s changed, not the charge.
Even More • The Prefix Hypo means two less oxygen’s are present then in –ate. • Example: Hyposulfite: SO2-2 • The Prefix Per- means one extra oxygen is present then in –ate. • Examples: • Perchlorate ClO4- • Chlorate ClO3- • Chlorite ClO2- • HypoChlorite ClO-
What if Hydrogen is in it? • The Prefix Bi means that a Hydrogen is added, and the charge is reduced by one. • Example: • BiCarbonate HCO3-1 • May also go by Hydrogen Carbonate.
Practice by writing the formula or name as required… • Iron (II) Phosphate • Stannous Fluoride • Potassium Sulfide • Ammonium Chromate • MgSO4 • FeCl3 Complete in your journal
Learning Check Match each set with the correct name: A.Na2CO3 1) magnesium sulfite MgSO3 2) magnesium sulfate MgSO4 3) sodium carbonate B. Ca(HCO3)2 1) calcium carbonate CaCO3 2) calcium phosphate Ca3(PO4)2 3) calcium bicarbonate Complete in your journal
Learning Check A. aluminum nitrate 1) AlNO3 2) Al(NO)3 3) Al(NO3)3 B. copper(II) nitrate 1) CuNO3 2) Cu(NO3)2 3) Cu2(NO3) C. Iron (III) hydroxide 1) FeOH 2) Fe3OH 3) Fe(OH)3 D. Tin(IV) hydroxide 1) Sn(OH)4 2) Sn(OH)2 3) Sn4(OH) Complete in your journal
Things to look for: • If cations have ( ), the number in parenthesis is their charge. • If anions end in -ide they are probably off the periodic table (Monoatomic) • If anion ends in -ate or –ite, then it is polyatomic
Write the opposite of what is shown; If name shown, write formula; If formula shown, write name. • aluminum sulfide 11. Na2S • barium arsenate 12. K2SO4 • copper (I) nitride 13. LiF • ammonium phosphate 14. Zn(NO3)2 • lead (IV) nitrate 15. FeCl3 • lithium oxalate 16. CaCO3 • calcium bicarbonate 17. AlBr3 • silver permanganate 18. Mg(NO3)2 • mercury (I) bromide 19. FeSO4 • chromium (III) sulfite 20. Pb(NO3)2 Complete in your journal