Week 08 Naming of ionic compounds.ppt PDF

IONIC COMPOUNDS Naming and Formula Writing  Properties of Ionic Compounds Ionic compounds are: – also known as salts – They are usually hard and brittle – Conduct electricity when molten or dissolved – Have very high melting and boiling points – Most are soluble in water – Norm...

IONIC COMPOUNDS Naming and Formula Writing  Properties of Ionic Compounds Ionic compounds are: – also known as salts – They are usually hard and brittle – Conduct electricity when molten or dissolved – Have very high melting and boiling points – Most are soluble in water – Normally composed of at least one metal and one nonmetal  Dissolution https://www.youtube.com/watch?v=6qPtw7HNKT0 Monatomic 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 (H, Li, Na, K, Rb, Cs) = always +1 Group 2 (Mg, Ca, Sr, Ba) = always +2 Aluminum = always +3 Zinc and Cadmium = always +2 Silver = always +1  Naming Positive 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  Naming Negative Ions All negative ions have their endings changed to –ide Oxygen becomes oxide Fluorine becomes Fluoride Nitrogen becomes Nitride Chlorine becomes Chloride Polyatomic Ions you have to know NAME FORMULA Acetate C2H3O2- Carbonate CO32- Chlorate ClO3- Cyanide CN- Hydroxide OH- Nitrate NO3- Nitrite NO2- Peroxide O-O2- Phosphate PO43- Sulfate SO42- Sulfite SO32- +  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+ / Cl Cl 3. Write the number of ions needed as subscripts BaCl2  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 – So, the Formula is BaF2  Another way – Drop, Swap, Reduce What is the formula for Aluminum Oxide? Al is always +3 Oxide is always -2 d “Cris al l e c Al3+, O2- o Als ross” ! —C DROP AND SWAP: Al2O3 REDUCE: 2 and 3 are lowest integers, so leave alone The Final Formula is Al2O3  Another example Magnesium Oxide Mg is +2 Oxide is -2 Mg2+, O2- DROP AND SWAP: Mg2O2 REDUCE: MgO, 2 and 2 divide each other out The Final Formula is MgO  Another example Magnesium Hydroxide Mg is +2 Hydroxide (OH) is -1 Mg2+, OH- DROP AND SWAP: Mg(OH)2  Another example Calcium Sulfate Ca is +2 Sulfate (SO4) is -2 Ca2+, SO4 2- DROP AND SWAP: Ca2(SO4)2 => CaSO4  Another example Calcium Phosphate Ca is +2 Phosphate (PO4) is -3 Ca2+, PO4 3- DROP AND SWAP: Ca3(PO4)2  Another example Ammounium Phosphate NH4 is + Phosphate (PO4) is -3 NH4 +, PO4 3- DROP AND SWAP: (NH4)3PO4  Another example Ammounium Chloride NH4 is + Chloride (Cl) is -1 NH4 +, Cl- DROP AND SWAP: NH4Cl  Learning Check Which is 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  Solution 1. Na+, S2- b) Na2S 2. Al3+, Cl- a) AlCl3 3. Mg2+, N3- c) Mg3N2  Naming Compounds Binary Ionic Compounds: 1. Cation first (+), then anion (-) 2. Monatomic cation = name of the element Ca2+ = calcium ion 3. Monatomic anion = root + -ide Cl- = chloride CaCl2 = calcium chloride  Naming Binary Ionic Compounds Examples: NaCl sodium chloride ZnI2 zinc iodide Al2O3 aluminum oxide  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 , Cu + 2+ Fe , Fe 2+ 3+ ROMAN S: AL NUMER copper (I) ion iron(II) ion copper (II) ion iron(III) ion I = one II = two e III = thre r… IV = fo u  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 the metals in 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 FeS (Fe2+) iron (II) sulfide  Transition Metals with Different Charges Iron (Fe) : 2+ or 3+ Copper (Cu): 1+ or 2+ Cobalt (Co): 2+ or 3+ Manganese (Mn), 2+, 3+, 4+ or 7+  Transition Metals with Different Charges Iron (Fe) : 2+ or 3+ Fe2+ is ferrous ion, Fe3+ is ferric ion FeCl2 is iron (II) chloride, ferrous chloride FeCl3 is iron (III) chloride, ferric chloride SO4 has always 2- charge FeSO4 is iron (II) sulfate, ferrous sulfate Fe2(SO4)3 is iron (III) sulfate, ferric sulfate  Transition Metals with Different Charges Copper (Cu) : + or 2+ Cu+ is cuprous ion, Cu2+ is cupric ion CuCl is copper (I) chloride, cuprous chloride CuCl2 is copper (II) chloride, cupric chloride SO4 has always 2- charge Cu2SO4 is copper (I) sulfate, cuprous sulfate CuSO4 is copper (II) sulfate, cupric sulfate  A Typical Exam Question Iron (II) chloride reacts with sodium hydroxide and the products are Iron (II) hydroxide and sodium chloride. Write and balance the reaction. FeCl2 + NaOH ==> Fe(OH)2 + NaCl Now, lets balance the reaction FeCl2 (aq) + 2NaOH (aq) ==> Fe(OH)2 (s) + 2NaCl (aq)  A Typical Exam Question Iron (III) chloride reacts with sodium hydroxide and the products are Iron (III) hydroxide and sodium chloride. Write and balance the reaction. FeCl3 + NaOH ==> Fe(OH)3 + NaCl Now, lets balance the reaction FeCl3 (aq) + 3NaOH (aq) ==> Fe(OH)3 (s) + 3NaCl (aq)  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- – 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 () Notice: The subscripts on Polyatomic ions are NEVER changed  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  Answers 1. Na+, PO4-3 c) Na3PO4 2. Al3+, NO3- – a) Al(NO3)3 3. NH4+, N3- – c) (NH4)3N