Copyright 2011 Pearson Education, Inc.Tro: Chemistry: A Molecular Approach, 2/e
Topic 1: ATOMS, ELEMENTS, MOLECULES AND COMPOUNDS
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Dalton’s Atomic Theory- Pg 45
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1. Each element is composed of tiny, indestructible particles called atoms
2. All atoms of a given element have the same mass and other properties that distinguish them from atoms of other elements
3. Atoms combine in simple, whole-number ratios to form molecules of compounds
4. In a chemical reaction, atoms of one element cannot change into atoms of another element
they simply rearrange the way they are attached
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Subatomic Particles in Atoms – Pg 49
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Atomic Number – pg 50
• Each element has a unique number of protons in its nucleus
• The number of protons in the nucleus of an atom is called the atomic numberthe elements are arranged on the Periodic Table in
order of their atomic numbers• Each element has a unique name and symbol
symbol either one or two lettersone capital letter or one capital letter and one
lowercase letter
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Copyright 2011 Pearson Education, Inc.Tro: Chemistry: A Molecular Approach, 2/e
Practice – Complete the table
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Al2713
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Practice – Complete the table
7
Al2713
C136
Mo9642
Cs13355
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About ¾ of the elements are classified as metals. They have a reflective surface, conduct heat and electricity better than other elements, and are malleable and ductile
Most of the remaining elements are classified as nonmetals. Their solids have a non-reflective surface, do not conduct heat and electricity well, and are brittle.
A few elements are classified as metalloids. Their solids have some characteristics of metals and some of nonmetals.
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Pg 55
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Metals – pg 55• Solids at room temperature, except Hg• Reflective surface
shiny• Conduct heat• Conduct electricity• Malleable
can be shaped• Ductile
can be drawn or pulled into wires• Lose electrons and form cations in
reactions• About 75% of the elements are metals• Lower left on the table
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Nonmetals-pg 55
• Found in all three states• Poor conductors of heat• Poor conductors of electricity• Solids are brittle• Gain electrons in reactions to
become anions• Upper right on the table
except H
Sulfur, S(s)
Bromine, Br2(l)
Chlorine, Cl2(g)
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Metalloids-pg 55
• Show some properties of metals and some of nonmetals
• Also known as semiconductors Properties of Silicon
shinyconducts electricity
does not conduct heat wellbrittle
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pg56
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= Alkali metals
= Alkali earth metals
= Noble gases
= Halogens
= Lanthanides
= Actinides
= Transition metals
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pg57
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Practice – What is the charge on each of the following ions?
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• potassium cation• sulfide anion• calcium cation• bromide anion• aluminum cation
K+
S2−
Ca2+
Br−
Al3+
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Practice – Complete the table
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3Al
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Practice – Complete the table
17
2Mg
2S
Br
3Al
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Atomic Mass-pg 57
• We generally use the average mass of all an element’s atoms found in a sample in calculations
• We call the average mass the atomic mass
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Elements and Compounds-pg 73
• Elements combine together to make an almost limitless number of compounds
• The properties of the compound are totally different from the constituent elements
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Chemical Bonds- pg 74• Compounds are made of atoms held
together by bonds• Chemical bonds are forces of attraction
between atoms• Ionic bonds result when electrons have been
transferred between atoms, resulting in oppositely charged ions that attract each othergenerally found when metal atoms bond to nonmetal
atoms• Covalent bonds result when two atoms share
some of their electronsgenerally found when nonmetal atoms bond together
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Molecular View of Elements and Compounds – pg 78
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Classifying Elements & Compounds – pg 77
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• Atomic elements = elements whose particles are single atoms
• Molecular elements = elements whose particles are multi-atom molecules
• Molecular compounds = compounds whose particles are molecules made of only nonmetals
• Ionic compounds = compounds whose particles are cations and anions
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Molecular Elements-pg77
H2
Cl2
Br2
I2
77A
N2 O2 F2
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• Certain elements occur as 2 atom molecules rule of 7’s
• Other elements occur as polyatomic moleculesP4, S8, Se8
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Ionic vs. Molecular Compounds-pg79
Propane – contains individual C3H8
molecules
Table salt – containsan array of Na+ ions
and Cl- ions
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Classify Each of the Following as Either an Atomic Element, Molecular Element,
Molecular Compound, or Ionic Compound
Aluminum, Al
Aluminum chloride, AlCl3
Chlorine, Cl2
Acetone, C3H6O
Carbon monoxide, CO
Cobalt, Co
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atomic element
ionic compound
molecular element
molecular compound
molecular compound
atomic element
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Ionic Compounds-pg81
• Compounds of metals with nonmetals are made of ionsmetal atoms form cations, nonmetal atoms form
anions
• No individual molecule units, instead they have a 3-dimensional array of cations and anions made of formula units
• Many contain polyatomic ionsseveral atoms attached together by covalent
bonds into one ion
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Example 3.3: Write the formula of a compound made from aluminum ions and oxide ions-pg82
1. Write the symbol for the metal cation and its charge
2. Write the symbol for the nonmetal anion and its charge
3. Charge (without sign) becomes subscript for other ion
4. Reduce subscripts to smallest whole number ratio
5. Check that the total charge of the cations cancels the total charge of the anions
Al3+ column 3A
O2− column 6A
Al+3 O2−
Al2O3
Al = (2)∙(+3) = +6O = (3)∙(−2) = −6
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Practice — What are the formulas for compounds made from the following ions?
• Potassium ion with a nitride ion
• Calcium ion with a bromide ion
• Aluminum ion with a sulfide ion
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Practice — What are the formulas for compounds made from the following ions?
• K+ with N3− K3N
• Ca2+ with Br− CaBr2
• Al3+ with S2− Al2S3
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Formula-to-NameRules for Ionic Compounds-pg82
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• Made of cation and anion• Some have one or more nicknames that are only
learned by experienceNaCl = table salt, NaHCO3 = baking soda
• Write systematic name by simply naming the ions if cation is:
metal with invariant charge = metal namemetal with variable charge = metal name(charge)polyatomic ion = name of polyatomic ion
if anion is:nonmetal = stem of nonmetal name + idepolyatomic ion = name of polyatomic ion
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• Metals with variable Charges
metals whose ions can have more than one possible charge
determine charge by charge on anion and cation
name = metal name with Roman numeral charge in parentheses
• Metals with invariant charge metals whose ions can
only have one possible chargeGroups 1A1+ & 2A2+, Al3+,
Ag1+, Zn2+, Sc3+
cation name = metal name
Naming Metal Cations-pg83
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Naming Monatomic Nonmetal Anion-pg83
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• Determine the charge from position on the Periodic Table
• To name anion, change ending on the element name to –ide
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Naming Binary Ionic Compounds forMetals with Invariant Charge-pg83
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• Contain metal cation + nonmetal anion• Metal listed first in formula and name
1. name metal cation first, name nonmetal anion second2. cation name is the metal name3. nonmetal anion named by changing the ending on the
nonmetal name to -ide
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Example: Naming Binary Ionic with Invariant Charge Metal
CsF
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1. Identify cation and anionCs = Cs+ because it is Group 1A
F = F− because it is Group 7A
2. Name the cationCs+ = cesium
3. Name the anionF− = fluoride
4. Write the cation name first, then the anion namecesium fluoride
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Practice — Name the following compounds
1. KCl
2. MgBr2
3. Al2S3
potassium chloride
magnesium bromide
aluminum sulfide
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Naming Binary Ionic Compounds forMetals with Variable Charge-pg84
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• Contain metal cation + nonmetal anion• Metal listed first in formula and name
1. name metal cation first, name nonmetal anion second
2. metal cation name is the metal name followed by a Roman numeral in parentheses to indicate its charge determine charge from anion charge common ions Table 3.4
3. nonmetal anion named by changing the ending on the nonmetal name to -ide
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Example: Naming binary ionic with variable charge metal
CuF2
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1. Identify cation and anionF = F− because it is Group 7
Cu = Cu2+ to balance the two (−) charges from 2 F−
2. Name the cationCu2+ = copper(II)
3. Name the anionF− = fluoride
4. Write the cation name first, then the anion namecopper(II) fluoride
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Name the following compounds
1. TiCl4
2. PbBr2
3. Fe2S3
titanium(IV) chloride
lead(II) bromide
iron(III) sulfide
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Example: Writing formula for binary ionic compounds containing variable charge metal
manganese(IV) sulfide1. Write the symbol for the
cation and its charge
2. Write the symbol for the anion and its charge
3. Charge (without sign) becomes subscript for other ion
4. Reduce subscripts to smallest whole number ratio
5. Check that the total charge of the cations cancels the total charge of the anions
Mn4+
S2-
Mn4+ S2− Mn2S4
Mn = (1)∙(4+) = +4S = (2)∙(2−) = −4
MnS2
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Practice — What are the formulas for compounds made from the following ions?
copper(II) ion with a nitride ion
iron(III) ion with a bromide ionCu2+ with N3− Cu3N2
Fe3+ with Br− FeBr3
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Compounds Containing Polyatomic Ions-pg86
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• Polyatomic ions are single ions that contain more than one atom
• Often identified by parentheses around ion in formula
• Name and charge of polyatomic ion do not change• Name any ionic compound by naming cation first
and then anion
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Some Common Polyatomic Ions-pg86
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Patterns for Polyatomic Ions
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1. Elements in the same column form similar polyatomic ions
same number of O’s and same charge
ClO3− = chlorate \ BrO3
− = bromate
2. If the polyatomic ion starts with H, add hydrogen- prefix before name and add 1 to the charge
CO32− = carbonate \ HCO3
− = hydrogen carbonate
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Periodic Pattern of Polyatomic Ions-ate groups
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Patterns for Polyatomic Ions
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• -ate ionchlorate = ClO3
−
• -ate ion + 1 O same charge, per- prefixperchlorate = ClO4
−
• -ate ion – 1 O same charge, -ite suffixchlorite = ClO2
−
• -ate ion – 2 O same charge, hypo- prefix, -ite suffixhypochlorite = ClO−
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Example: Naming ionic compounds containing a polyatomic ion
Na2SO4
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1. Identify the ionsNa = Na+ because in Group 1A
SO4 = SO42− a polyatomic ion
2. Name the cationNa+ = sodium, metal with invariant charge
3. Name the anionSO4
2− = sulfate
4. Write the name of the cation followed by the name of the anion
sodium sulfate
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Example: Naming ionic compounds containing a polyatomic ion
Fe(NO3)3
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1. Identify the ionsNO3 = NO3
− a polyatomic ion
Fe = Fe3+ to balance the charge of the 3 NO3−
2. Name the cationFe3+ = iron(III), metal with variable charge
3. Name the anionNO3
− = nitrate
4. Write the name of the cation followed by the name of the anion
iron(III) nitrate
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Name the Following Compounds
1. NH4Cl
2. Ca(C2H3O2)2
3. Cu(NO3)2
ammonium chloride
calcium acetate
copper(II) nitrate
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Example – Writing formula for ionic compounds containing polyatomic ion
Iron(III) phosphate1. Write the symbol for the
cation and its charge
2. Write the symbol for the anion and its charge
3. Charge (without sign) becomes subscript for other ion
4. Reduce subscripts to smallest whole number ratio
5. Check that the total charge of the cations cancels the total charge of the anions
Fe3+
PO43−
Fe3+ PO43− Fe3(PO4)3
Fe = (1)∙(3+) = +3PO4 = (1)∙(3−) = −3
FePO4
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Practice — What are the formulas for compounds made from the following ions?
aluminum ion with a sulfate ion
chromium(II) with hydrogen carbonate
Al3+ with SO42− Al2(SO4)3
Cr2+ with HCO3− Cr(HCO3)2
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Hydrates-pg87
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• Hydrates are ionic compounds containing a specific number of waters for each formula unit
• Water of hydration often “driven off” by heating
• In formula, attached waters follow ∙ CoCl2∙6H2O
• In name attached waters indicated by prefix+hydrate after name of ionic compound CoCl2∙6H2O = cobalt(II) chloride hexahydrate
CaSO4∙½H2O = calcium sulfate hemihydrate
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Cobalt(II) chloride hexahydrate
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Practice
What is the formula of magnesium sulfate heptahydrate?
What is the name of NiCl2•6H2O?
Mg2+ + SO42−
MgSO4
MgSO47H2O
Cl− Ni2+
nickel(II) chloridenickel(II) chloride hexahydrate
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Writing Names of Binary Molecular Compounds of Two Nonmetals-pg88
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1. Write name of first element in formulaa) element furthest left and down on the Periodic Tableb) use the full name of the element
2. Writes name the second element in the formula with an -ide suffixa) as if it were an anion, however, remember these
compounds do not contain ions!3. Use a prefix in front of each name to indicate the
number of atomsa) Never use the prefix mono- on the first element
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Subscript – Prefixes
• Drop last “a” if name begins with a vowel
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• 1 = mono- not used on first nonmetal
• 2 = di-• 3 = tri-• 4 = tetra-• 5 = penta-
• 6 = hexa-
• 7 = hepta-• 8 = octa-• 9 = nona-• 10 = deca-
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Example: Naming binary molecular BF3
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1. Name the first elementboron
2. Name the second element with an –idefluorine fluoride
3. Add a prefix to each name to indicate the subscriptmonoboron, trifluoride
4. Write the first element with prefix, then the second element with prefix
a) drop prefix mono from first elementboron trifluoride
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Name the Following
NO2
PCl5
I2F7
nitrogen dioxide
phosphorus pentachloride
diiodine heptafluoride
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Example: Binary Moleculardinitrogen pentoxide
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• Identify the symbols of the elements
nitrogen = N
oxide = oxygen = O• Write the formula using prefix number for subscript
di = 2, penta = 5
N2O5
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Write Formulas for the Following
dinitrogen tetroxide
sulfur hexafluoride
diarsenic trisulfide
N2O4
SF6
As2S3
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Acids-pg89• Acids are molecular compounds that form H+
when dissolved in waterto indicate the compound is dissolved in water (aq)
is written after the formulanot named as acid if not dissolved in water
• Sour taste• Dissolve many metals
such as Zn, Fe, Mg; but not Au, Ag, Pt
• Formula generally starts with He.g., HCl, H2SO4
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Reaction of Acids with Metals
H2 gas
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Acids
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• Contain H+1 cation and anion in aqueous solution
• Binary acids have H+1 cation and nonmetal anion
• Oxyacids have H+ cation and polyatomic anion
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Naming Binary Acids
• Write a hydro prefix• Follow with the nonmetal name• Change ending on nonmetal name to –ic• Write the word acid at the end of the name
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Example: Naming binary acids HCl(aq)
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1. Identify the anionCl = Cl−, chloride because Group 7A
2. Name the anion with an –ic suffixCl− = chloride chloric
3. Add a hydro- prefix to the anion namehydrochloric
4. Add the word acid to the endhydrochloric acid
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Naming Oxyacids-pg90
• If polyatomic ion name ends in –ate, then change ending to –ic suffix
• If polyatomic ion name ends in –ite, then change ending to –ous suffix
• Write word acid at end of all names
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Example: Naming oxyacids H2SO4(aq)
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1. Identify the anionSO4 = SO4
2− = sulfate
2. If the anion has –ate suffix, change it to –ic. If the anion has –ite suffix, change it to -ous
SO42− = sulfate sulfuric
3. Write the name of the anion followed by the word acid
sulfuric acid(kind of an exception, to make it sound nicer!)
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Example: Naming oxyacids H2SO3(aq)
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1. Identify the anionSO3 = SO3
2− = sulfite
2. If the anion has –ate suffix, change it to –ic. If the anion has –ite suffix, change it to -ous
SO32− = sulfite sulfurous
3. Write the name of the anion followed by the word acid
sulfurous acid
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Name the Following
H2S
HClO3
HNO2
hydrosulfuric acid
chloric acid
nitrous acid
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Writing Formulas for Acids
• When name ends in acid, formulas starts with H• Write formulas as if ionic, even though it is
molecular• Hydro prefix means it is binary acid, no prefix
means it is an oxyacid• For oxyacid, if ending is –ic, polyatomic ion
ends in –ate; if ending is –ous, polyatomic ion ends in –ous
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Example: Binary Acidshydrosulfuric acid
1. Write the symbol for the cation and its charge
2. Write the symbol for the anion and its charge
3. Charge (without sign) becomes subscript for other ion
4. Add (aq) to indicate dissolved in water
5. Check that the total charge of the cations cancels the total charge of the anions
H+
S2−
H+ S2− H2S
H = (2)∙(1+) = +2S = (1)∙(2−) = −2
H2S(aq)
in all acids the cation is H+
hydro meansbinary
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Example: Oxyacidscarbonic acid
1. Write the symbol for the cation and its charge
2. Write the symbol for the anion and its charge
3. Charge (without sign) becomes subscript for other ion
4. Add (aq) to indicate dissolved in water
5. Check that the total charge of the cations cancels the total charge of the anions
H+
CO32−
H+ CO32− H2CO3
H = (2)∙(1+) = +2CO3 = (1)∙(2−) = −2
H2CO3(aq)
in all acids the cation is H+
no hydro meanspolyatomic ion
-ic means -ate ion
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Practice — What are the formulas for the following acids?
H+ with ClO2– HClO2
H+ with PO43– H3PO4
H+ with Br– HBr
chlorous acid
phosphoric acid
hydrobromic acid
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