Ionic%20Compounds:%20Bonding%20Nomenclature

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Ionic CompoundsBondingNomenclature

• Edward Wen

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Bonding Theories

• Bonding the way atoms attach to make molecules
• How and Why atoms attach together in the manner
  they do is central to chemistry
• An understanding of bonding would
• Predict the composition of compounds
• predict the shapes of molecules and properties of
  substances
• design and build molecules with particular sets
  of chemical and physical properties, for such as
  drug design in pharmaceutical industries.

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Lewis Bonding Theory

• Atoms bond with each other because bonding
  results in a more stable Electron Configuration,
  aka Nobel Gas Configuration (1s2) or (ns2np6)
• How to achieve NG configuration?
• either transferring or sharing electrons so that
  all atoms obtain an Outer Shell with 8 electrons
  (like Noble gases)
• ? Octet Rule
• Some exceptions H, He, Li, Be.
• How to remember? Everyone wants to have an
  electron configuration like a Noble Gas

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Lewis Symbols of Atoms

• also Electron Dot Symbols
• Symbol of element Nucleus and Inner electrons
• Dots around the Symbol as Valence electrons
• put one electron on each side first, then pair
• elements in the same group have the same number
  of valence electrons ? same Lewis dot symbols

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Everyone Atom Want to Be Like a Noble Gas!

• Alkali Metals (Group IA, valence electron ns1) as
  a group are the most reactive metals
• they react with many things and do so rapidly
• Halogens (Group VIIA, valence electron ns2np5)
  are the most reactive group of nonmetals
• one reason for their high reactivity they are
  only ONE electron away from having a very stable
  electron configuration
• the same as a noble gas

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Stable Electron ConfigurationAnd Ion Charge

• Metals ? Cations
• by losing enough electrons to get the same
  electron configuration as the previous noble gas
• Nonmetals ? Anions
• by gaining enough electrons to get the same
  electron configuration as the next noble gas

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Ionic Bonds

• Bonding Metal Nonmetal
• Metal loses electrons to form cation ( charge)
• Nonmetal gains electrons to form anion (-
  charge)
• ? Ionic bond results from - attraction
  (Coulombic force)
• larger charge stronger attraction
• smaller ion stronger attraction
• Lewis Theory allows us to predict the correct
  formulas of ionic compounds

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Lewis Symbols of Ions

• Cations (Cn) have no valence electrons
• Valence electron(s) are Lost in the cation
  formation
• Anions (An-) 8 valence electrons
• Electrons gained in the formation of the anion

Li Li 1e-


F 1e- F-


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Chemical Formula

• Chemical formula describe the compound by
  describing the number and type of each atom in
  the simplest unit of the compound
• molecules or ions (Table salt Cl, Na-)
• Element represented by its letter symbol H
  instead of hydrogen Na instead of Sodium
• Atoms of each element the right of the element
  as a subscript, H2O (unless if there is only one
  atom, the 1 subscript is not written)
• Polyatomic groups (multiple atoms in group,
  example CO3) are placed in parentheses if more
  than one

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Ionic Compounds

• Ions Metals (Cation Mx) and Nonmetals (Anion
  Ny-)
• No individual molecules!!
• have a 3-dimensional array of cations and anions
  made of formula units NaCl, MgO
• Na Cl- Na Cl- Na Cl-
• Cl- Na Cl- Na Cl- Na
• Na Cl- Na Cl- Na Cl-

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Ionic Compounds

• Name first Cation, followed by Anion
• example NaCl Sodium Chloride
• Cation
• Fixed charge vs. Variable charge
• Polyatomic ion ammonium NH4
• Anion
• Nonmetal Chloride Cl-, Oxide O2-
• Polyatomic ion SO42- , OH- , NO3-

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Physical Properties of Ionic Compounds

• Strong Coulombic attraction between the cations
  and anions (M ? ?X-)
• High melting points and high boiling points, thus
  mostly as Solid state in room temperature.
• Many dissolves well in water and conduct
  electricity. Water molecule is polar
  (Hd-Od--Hd) so it can attract both cation and
  anion.

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Metal Cations with Fixed Charge

• Groups IA, IIA, AZA
• only have one possible charge
• Groups IA, IIA, Ag, Zn2, Al3
• Charge by position on the Periodic Table
• IA 1, IIA 2,
• Ag (IB), Zn2(IIB) Al3(IIIA)
• Name is the same as the element
• Ag silver ion
• Ca2 calcium ion

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Metal Cations with Variable Charges

• Common Examples Fe2/3, Cu/2, Cr3/6,
  Mn2/4, Mn2/4, Pb2/4, Sn2/4, etc )
• Determine charge by charge on anion
• Name with Roman numeral to indicate charge
• Cu copper(I) ion Pb4 lead(IV) ion
• Or use common name (lower charge ous, higher
  charge ic)
• Cu cuprous Cu2 cupric
• Fe2 ferrous Fe3 ferric
• Sn2 stannous Sn4 stannic

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Metal Cations Remember the fixed charge cations!
Fixed charge
Variable charge
Al
Zn
Ag
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Monatomic Nonmetal Anion (An-)

• How much is the charge? ?the position on the
  Periodic Table
• Name of the anion change ending on the element
  name to ide

4A -4 5A -3 6A -2 7A -1
C4- carbide N3- nitride O2- oxide F- fluoride
Si4- silicide P3- phosphide S2- sulfide Cl- chloride
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Net charge of Ionic Compound 0

• Net charge
• Positive charge from Cation(s) Negative
  charge from Anion(s)
• 0
• Example Compound Al2S3, the Net charge 2 x
  (3) 3 x (-2) 6 - 6 0

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Name of Ionic Compounds

• Cation
• Fixed charge cation Na gt Sodium
• Variable charge cation metal name(charge)
• Fe3 gt Iron(III)
• Or use Common Name Fe3 gt Ferric
• Polyatomic ion NH4 gt Ammonium
• Anion
• Nonmetal anion -ide, O2- gt oxide
• Polyatomic ion SO42- gt Sulfate

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Example Naming CsF

• Classify the compound as ionic or covalent
• For ionic metal ions as fixed charge or variable
  charge?
• Fixed charge metal cation Name accordingly.
• cesium fluoride

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Variable charge metal comopound

• Metal listed first in formula name
• Metal cation ? Nonmetal anion
• metal cation ? Metal(Roman Numeral) to indicate
  its charge. Iron(II), Copper(I)
• determine charge from anion charge
• Alternatively, use common name
• Nonmetal anion ? Nonmetal name ended with ide
  Chloride, Oxide

Example Iron(II) chloride, Copper(I) oxide
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How to find the charge on metal ions with
variable charge?

• Example Name Compound Fe2O3
• Since the sum of all charges equals zero, the
  charge on iron ions are unknown and oxide ion has
  2 charge, then we have
• 2 x Fe 3 x (-2) 0
• Fe 3, each iron ion has a charge of 3
• Name iron(III) oxide
• Key knowing the charge on ANIONs!

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Example Naming variable charge metal compound
Fe2O3

• Identify the compound as ionic or covalent
• Identify the metal ion as fixed charge or
  variable charge.
• Find the charge of metal ion using the charge on
  the known anion
• Note What is the name and charge of anion O?
• 4. Name accordingly.
• Iron(III) oxide Or Ferric chloride

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Practice Naming Ionic compounds

• HgF2
• CuI2
• Cr2S3
• SnCl4
• Mg3N2
• Hg2Cl2

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Naming Ionic compounds Hints find type II ion
charge from anion

• HgF2 Two F- -2
• CuI2 Two I- -2
• CaCl2 both fixed charges
• Cr2O3 Three O2- -6
• SnBr4 Four Br- -4
• Mg3N2 both fixed charges
• Ag2S both fixed charges

• HgF2 Two F- -2 Hg 2
• CuI2 Two I- -2 Cu 2
• CaCl2 both fixed charges
• Cr2O3 Three O2- -6 Cr 3
• SnBr4 Four Br- -4 Sn 4
• Mg3N2 both fixed charges
• Ag2S both fixed charges

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Answer key names of ionic compounds

• HgF2 Mercury(II) fluoride
• CuI2 copper(II) iodide
• CaCl2 calcium chloride
• Cr2O3 chromium(III) oxide
• SnBr4 tin(IV) bromide
• Mg3N2 magnesium nitride
• Ag2S silver sulfide

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Polyatomic Anions -ATE ions
CO32- carbonate NO3- nitrate
SiO32- silicate PO43- phosphate SO42- sulfate ClO3- chlorate
AsO43- arsenate SeO42- selenate BrO3- bromate
IO3- iodate
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Polyatomic Ions
Mg(NO3)2 compound called magnesium nitrate
CaSO4 compound called calcium sulfate
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Polyatomic IonsNitrate NO3-, Sulfate SO42-
Mg(NO3)2 compound called magnesium nitrate
CaSO4 compound called calcium sulfate
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Periodic Pattern of Polyatomic Ions-ate groups
IIIA IVA VA VIA VIIA
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Patterns for Polyatomic Ions

• elements in the same Group form similar
  polyatomic ions
• same number of Os and same charge
• ClO3- chlorate (-1 charge)
• BrO3- bromate (-1 charge)
• if the polyatomic ion starts with H, the name
  adds hydrogen- prefix before name and add 1 to
  the charge
• CO32- carbonate \ HCO3-1 hydrogen carbonate

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Patterns for Polyatomic Ions

• -ate ion
• chlorate ClO3-
• -ate ion 1 O ? same charge, per- prefix
• perchlorate ClO4-
• -ate ion 1 O ? same charge, -ite suffix
• chlorite ClO2-
• -ate ion 2 O ? same charge, hypo- prefix, -ite
  suffix
• hypochlorite ClO-

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Polyatomic Anions -ite, hypo- -ite, (-ate),
per- -ate
ClO- hypochlorite
NO2- nitrite PO33- phosphite SO32- sulfite ClO2- chlorite
NO3- nitrate PO43- phosphate SO42- sulfate ClO3- chlorate
ClO4- perchlorate
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-ATE/-ITE ions in Our Lives
ClO- (bleach)
NO2- (preserve meat) PO33- (plant medicine) SO32- (wine, oxygen buster) ClO2- (bleach, disinfect)
NO3- (fertilizer, explosives) PO43- (bone/teeth, fertilizer, soda) SO42- (plaster, car battery, sea salt) ClO3- (older pyrotechnics)
ClO4- (pyrotechnics, solid fuel rocket)
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Polyatomic Ions to Remember
Name Formula
acetate C2H3O2
carbonate CO32
hydrogen carbonate (aka Bicarbonate) HCO3
hydroxide OH
nitrate NO3
nitrite NO2
permanganate MnO4
chromate CrO42
dichromate Cr2O72
ammonium NH4
Name Formula
hypochlorite ClO
chlorite ClO2
chlorate ClO3
perchlorate ClO4
sulfate SO42
Hydrogen sulfate (aka Bisulfate) HSO4
sulfite SO32
Hydrogen sulfite (aka Bisulfite) HSO3
cyanide CN
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Polyatomic Ions in Our Lives
C2H3O2 In vinegar as acetic acid
CO32 Soda drink
HCO3 Baking soda, baking power, acid spill neutralizer
OH In liquid plumber/Drano as NaOH
MnO4 Disinfectant, aging for movie making
CrO42 Chrome plating (faucet, etc.)
CN Highly Poisonous Plant seeds blue pigment
NH4 Fertilizer metabolic waste from animals
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Other Polyatomic Ions in Our Lives
ClO- (bleach)
NO2- (preserve meat) PO33- (plant medicine) SO32- (wine, oxygen buster) ClO2- (bleach, disinfect)
NO3- (fertilizer, explosives) PO43- (bone/teeth, fertilizer, soda) SO42- (plaster, car battery, sea salt) ClO3- (older pyrotechnics)
ClO4- (pyrotechnics, solid fuel rocket)
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Compounds Containing Polyatomic Ions

• Fixed charge metal cation Polyatomic ion NaNO3
• Variable charge metal cation Polyatomic ion
  CuSO4
• Polyatomic cation Nonmetal ion (-ide) NH4Cl
• Polyatomic cation Polyatomic ion (NH4)2SO4
• Important! If, and only if, more than ONE
  polyatomic ions are present in a formula, use
  parenthesis and subscript to indicate the number
  of polyatomic ions

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Example Naming Ionic with Polyatomic Ion Na2SO4

• Ionic or covalent compound?
• Ionic fixed charge or variable charge metal
  cation?
• fixed charge metal cation Name accordingly.
• Sodium sulfate

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Example Naming Ionic with Polyatomic Ion
Fe(NO3)3

• Ionic or covalent compound?
• Ionic fixed charge or variable charge metal
  cation?
• Variable charge metal cation determine the
  charge based on the charge of anion
• Note what is the name and charge on NO3?
• 4. Name accordingly.
• Iron(III) nitrate

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Practice Naming Ionic compounds

• Hg2SO4
• CuClO3
• Zn(NO3)2
• FeCO3
• Sn(SO3)2
• CoPO4
• Al(ClO4)3

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Hints Naming Ionic compounds

• Hg2SO4 charge of sulfate -2
• CuClO3 charge of chlorate -1
• Zn(NO3)2 charge of nitrate -1
• FeCO3 charge of carbonate -2
• Sn(SO3)2 charge of sulfite -2
• CoPO4 charge of phosphate -3
• Al(ClO4)3 charge of perchlorate -1

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Keys Naming Ionic compounds

• Hg2SO4 mercury(I) sulfate
• CuClO3 copper(I) chlorate
• Zn(NO3)2 zinc nitrate
• FeCO3 iron(II) carbonate
• Sn(SO3)2 tin(IV) sulfite
• CoPO4 cobalt(III) phophate
• Al(ClO4)3 aluminum perchlorate

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Review Naming Compounds

• CuSO3 copper(II) sulfite
• AgClO silver hypochlorite
• Al2S3 aluminum sulfide
• FeI2 iron(II) iodide
• Sn(NO3)4 tin(IV) nitrate
• Ba3(PO4)2 barium phosphate
• (NH4)2S ammonium sulfide

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Write Chemical Formula using the charge of known
ions

• Example Compound between Ca2 and PO43- , the
  number of ions of each needs to be 3 and 2, so
  that the combined charge
• 3 x (2) 2 x (-3) 0
• Therefore the formula for the compound is
  Ca3(PO4)2

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Write Chemical Formula using the charge of known
ions

• Criss-Cross-Simplify
• The charge of an ion turns into the subscript
  (the number) of the counterpart ion
• Pb4 O2- ? Pb2O4
• Since the subscripts in an ionic compound
  represents the RATIO among the ions, the
  subscripts need to be simplified when there is
  common denominator
• Pb2O4 ? PbO2

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Key for Writing formulas (I) use
criss-cross-reduce

• copper(II) chloride CuCl2
• aluminum oxide Al2O3
• magnesium phosphide Mg3P2
• iron(II) bromide FeBr2
• lead(II) sulfide FeS
• zinc iodide ZnI2
• sodium nitride Na3N

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Practice Write Chemical Formulae

• Chromium(II) Chloride
• Cesium phosphate
• Lead(II) oxide
• Zinc nitrate
• Iron(III) sulfite
• Strontium nitride
• Ammonium carbonate

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Key Write Chemical Formulae

• Chromium(II) Chloride
• Cesium phosphate
• Lead(II) oxide
• Zinc nitrate
• Iron(III) sulfite
• Strontium nitride
• Ammonium carbonate

• CrCl2
• Cs3PO4
• PbO
• Zn(NO3)2
• Fe3(SO3)2
• Sr3N2
• (NH4)2CO3