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Ionic Compounds Nomenclature Introduction • We use the periodic table to tell us the most • commonly expected charges for the ions of elements. For example: • Group 1 (1A) elements have a 1+ charge. • Na becomes Na+ • Group 2 (2A) elements have a 2+ charge. • Mg becomes Mg2+ • Group 13 (3A) elements have a 3+ charge. • Al becomes Al3+ Introduction • We use the periodic table to tell us the most • commonly expected charges for the ions of elements. For example: • Group 15 (5A) elements have a 3- charge. • N becomes N3- • Group 16 (6A) elements have a 2- charge. • O becomes O2• Group 17 (7A) elements have a 1- charge. • Cl becomes Cl- Forming Ionic Compounds • We form ionic compounds by matching the charges of the ions to form a neutral compound. • For example: • Combining Na+ with Cl- gives NaCl. • Combining Ca2+ with S2- gives CaS. • Combining Ga3+ with N3- gives GaN. • Each of these combinations gives a neutral compound. Forming Ionic Compounds • More complex combinations of ions also need to be balanced to produce neutral compounds. • For example: • Combining Na+ with O2- gives Na2O. • Combining Ca2+ with Br- gives CaBr2. • Combining Al3+ with F- gives AlF3. • Each of these combinations gives a neutral compound. Forming Ionic Compounds • For even more complex combinations of ions we use a trick to produce neutral compounds. • For example: 2 2+ 2+ 3• Combining Ca with N : Ca 3 3N 2+, we • We To find canthe useproper this “criss-cross” number of Ca when ever use wethe have 3 • a complex of the N3-. combination of ions. To find the proper number of N3-, we use the 2 of the Ca2+. Binary Ion Nomenclature • When we name binary ionic compounds (ionic compounds made from the ions of two elements), we name the cation first followed by the anion. • In general, cations that are metals are given the name of the elemental metal. • NaCl is named sodium chloride. • BaF2 is named barium fluoride. • Ca3P2 is named calcium phosphide. Binary Ion Nomenclature • When we name binary ionic compounds (ionic compounds made from the ions of two elements), we name the cation first followed by the anion. • In general, anions are given the name of the element followed by the suffix “-ide.” • NaCl is named sodium chloride. • BaF2 is named barium fluoride. • Ca3P2 is named calcium phosphide. Binary Ion Nomenclature • The single element anions are: nitride 3C phosphide N P oxide 21- O S F Cl fluoride sulfide chloride bromide As Se arsenide Br I selenide iodide Binary Ion Nomenclature • Transition (d-block) metals most commonly have a Sc2+ 2+Fe 2+ 3+ 2+3+ 3+ + 2+ 2+ 2+ 3+ 3+ 4+ 2+ Mn , Mn Co , Fe , Co V Cr ,TiV , Cr ,V Cu , Cu2+ 2+ Zn 2+ charge. Mo Sn2+, +Sn4+ Ag Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Au+, Au3+ Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po Lr Rf Db Sg Bh Hs Mt Ds Rg Uub • • Pb2+, Pb4+ There are exceptions to this rule. Some transition and main group metals have two or more common charges. Binary Ion Nomenclature • Since these cations can have different charges, we need a nomenclature that will distinguish between the different cations. • The Stock system is used to identify different ions. • We use the element name followed by the charge of the ion in parenthesis. • For example: • Cu+ is written as copper(I) • Cu2+ is written as copper(II) • Pb2+ is written as lead(II) Binary Ion Nomenclature • Examples of Stock nomenclature: • CuCl = copper(I) chloride • CuCl2 = copper(II) chloride • FeO = iron(II) oxide • Fe2O3 = iron(III) oxide • PbS = lead(II) sulfide • PbS2 = lead(IV) sulfide • VO = vanadium(II) oxide • V2O3 = vanadium(III) oxide Polyatomic Ion Nomenclature • Polyatomic ions are single ions that are made up of several atoms. • Examples of polyatomic ions include: • nitrate: NO3• sulfate: SO42• phosphate: PO43• ammonium: NH4+ • nitrite: NO2- Polyatomic Ion Nomenclature • Each of these units acts as a single ion. • Nitrate (1-)acts in the same manner as chloride. • Sodium nitrate is NaNO3. • Calcium nitrate is Ca(NO3)2. • Aluminum nitrate is Al(NO3)3. • Sulfate (2-) acts in the same manner as oxide. • Sodium sulfate is Na2SO4. • Calcium sulfate is CaSO4. • Cations: • Polyatomic Ion Nomenclature ammonium: NH4+ dimercury: Hg22+ Anions: nitrate: NO3sulfate: SO42nitrite: NO2sulfite: SO32cyanide: CNcarbonate: CO32silicate: SiO32hydroxide: OHperchlorate: ClO4chromate: CrO42dichromate: Cr2O72chlorate: ClO32oxalate: C O 2 4 chlorite: ClO2 hypochlorite: ClOphosphate: PO43acetate: CH3COOphosphite: PO33hydrogen carbonate: HCO3- Polyatomic Ion Nomenclature • When we form ionic compounds from polyatomic • ions, we treat the polyatomic ions as individual units of charge. For example: • barium 2+ and nitrate 1Ba2+ (NO3)- Ba(NO3)2 barium nitrate We use the criss-cross trick to find the formula of the compound. Polyatomic Ion Nomenclature • When we form ionic compounds from polyatomic • ions, we treat the polyatomic ions as individual units of charge. For example: • ammonium 1+ and sulfate 2(NH4)+ (SO4)2- (NH4)2SO4 ammonium sulfate We use the criss-cross trick to find the formula of the compound. Knowledge Check • Determine the formulas of the following compounds: 1.sodium carbonate 2.copper(II) sulfate + CO 2Na Na 2 (CO 3 3) 2CuSO Cu2+ (SO 4 4) 4+ 3(PO ) (PO ) 3.lead(IV) phosphate PbPb 4 3 4 4 4.aluminum nitrite Al(NO Al3+ (NO 2)3 2) + 25.ammonium sulfide (NH4)(NH 4)2S S Knowledge Check • Determine the names of the following compounds: 1.Fe2(CrO4)3 iron(III) chromate 2.VO2 vanadium(IV) oxide 3.Cr(CH3COO)2 chromium(II) acetate 4.AuPO4 gold(III) phosphate 5.NaClO sodium hypochlorite