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Naming and Writing Naming and Writing FormulasFormulas
Types of CompoundsTypes of Compounds
There are two types of compounds.There are two types of compounds.
Ionic: Ionic: a metal and an nonmetala metal and an nonmetal
Covalent: Covalent:
contain two nonmetalscontain two nonmetals
Ionic CompoundsIonic Compounds Must contain a positive ion (cation) Must contain a positive ion (cation)
and negative ion (anion).and negative ion (anion).
The cation (metal) is written first, the The cation (metal) is written first, the anion (nonmetal) is written second.anion (nonmetal) is written second.
The total charge on the compound The total charge on the compound must equal 0.must equal 0.
Naming Binary Ionic Naming Binary Ionic CompoundsCompounds
#1 – Name the metal (written on periodic #1 – Name the metal (written on periodic table)table)
#2 – Name the nonmetal, #2 – Name the nonmetal, changing the ending to –idechanging the ending to –ide..
Examples:Examples: MgOMgO CaClCaCl22 NaBrNaBr SrSr33PP22
magnesium oxidemagnesium oxide calcium chloridecalcium chloride sodium bromidesodium bromide strontium strontium
phosphide phosphide
Writing FormulasWriting Formulas
The subscripts tell how many of each The subscripts tell how many of each atom you have. (The overall charge atom you have. (The overall charge must equal zero!!)must equal zero!!)
EXAMPLE: Write the chemical EXAMPLE: Write the chemical formula for the compound containing formula for the compound containing Al and Br.Al and Br.
#1 – determine the charges#1 – determine the charges
AlAl+3+3 Br Br-1-1
#2 – cross the charges.#2 – cross the charges.
AlAl+3+3 Br Br-1-1
#3 – Write the formula, simplify if #3 – Write the formula, simplify if needed needed
AlBrAlBr33
31
Try this one…Try this one…
Write the chemical formula for the Write the chemical formula for the compound containing Mg and Scompound containing Mg and S
#1 – determine the charges#1 – determine the charges
MgMg+2+2 S S-2-2
#2 – cross the charges.#2 – cross the charges.
MgMg+2+2 S S-2-2
#3 – Write the formula, simplify if #3 – Write the formula, simplify if needed needed
MgMg22SS22
MgSMgS
22
Ionic Compounds with Ionic Compounds with Polyatomic IonsPolyatomic Ions
#1 – name the 1st part of the compound#1 – name the 1st part of the compound #2 – name the 2nd part#2 – name the 2nd part If it is a polyatomic ion, If it is a polyatomic ion, DO NOTDO NOT change change
the endingthe ending If it is a nonmetal, change to –ide.If it is a nonmetal, change to –ide. Examples:Examples: CaCOCaCO33
NaNa33SOSO44
(NH(NH44))22SS
Calcium carbonateCalcium carbonate Sodium sulfateSodium sulfate Ammonium sulfideAmmonium sulfide
Writing Formulas:Writing Formulas: Same rules apply, except if the polyatomic Same rules apply, except if the polyatomic
ion gets a subscript you MUST use ion gets a subscript you MUST use parentheses around it.parentheses around it.
Example:Example: Write the formula for sodium hydroxide.Write the formula for sodium hydroxide.
NaNa+1+1 OH OH-1-1
NaOHNaOH
11
Writing Formulas for Writing Formulas for Polyatomic CompoundsPolyatomic Compounds
Calcium phosphateCalcium phosphate
CaCa+2+2 PO PO44-3-3
CaCa33(PO(PO44))22
23
Aluminum nitriteAluminum nitrite
AlAl+3+3 NO NO22-1-1
Al(NOAl(NO22))33
31
Homework
Page 221
Problems 19, 20, 21 and 22
Page 233
Problem 83
Compounds Containing Compounds Containing Metals with Variable Metals with Variable
ChargesCharges
Variable ChargesVariable Charges(Transition Metals)(Transition Metals)
Metals in Group 1, Group 2, Zinc Metals in Group 1, Group 2, Zinc (+2), Silver (+1) and Aluminum only (+2), Silver (+1) and Aluminum only have one charge. have one charge.
The rest have The rest have variablevariable charges so charges so we have to we have to telltell what charge the ion what charge the ion has in our compound when we name has in our compound when we name it.it.
NamingNaming
#1 – Name the metal.#1 – Name the metal. #2 – Add a roman numeral #2 – Add a roman numeral telling telling
the charge on the metal in the charge on the metal in parentheses.parentheses.
I-1 II-2 III-3 IV-4 V-5 VI-6 VII-7I-1 II-2 III-3 IV-4 V-5 VI-6 VII-7 #3 – Name the negative ion #3 – Name the negative ion as as
before.before.
ExampleExample
CrOCrO O is a -2 chargeO is a -2 charge To make a neutral compound, Cr To make a neutral compound, Cr
must be a +2.must be a +2. Chromium (II) oxideChromium (II) oxide
FeClFeCl33 Cl is a -1 chargeCl is a -1 charge There are 3 chlorine ions There are 3 chlorine ions -3 -3 The ONE Fe must be a +3The ONE Fe must be a +3 Iron (III) chlorideIron (III) chloride
CoCOCoCO33
Carbonate is a -2Carbonate is a -2 Co is a +2Co is a +2 Cobalt (II) carbonateCobalt (II) carbonate
NiNi33(PO(PO44))22
Phosphate = -3 x 2 = -6Phosphate = -3 x 2 = -6 There are 3 nickel atoms so each one There are 3 nickel atoms so each one
= +2 to equal +6= +2 to equal +6 Nickel (II) phosphateNickel (II) phosphate
Mn(SOMn(SO44))22
Sulfate is -2, there are two Sulfate is -2, there are two -4 -4 so the ONE Manganese = +4so the ONE Manganese = +4 Manganese (IV) sulfateManganese (IV) sulfate
Writing formulas:Writing formulas:
Rules are the same as before.Rules are the same as before.
copper (III) oxidecopper (III) oxide
CuCu+3+3 O O-2-2
CuCu22OO33
32
Manganese (IV) sulfideManganese (IV) sulfide
MnMn+4+4 S S-2-2
MnMn22SS44
MnSMnS22
42
Iron (II) nitrateIron (II) nitrate
FeFe+2+2 NO NO33-1-1
Fe(NOFe(NO33))22
21
Classwork
Page 223
Problems 28, 29, 30, 31 and 32
Page 233
Problem 82