Formulas and Names-Inorganic Compounds

Formulas and Names of Inorganic Compounds Naming and Writing Ionic Formulas

Copyright © 2009 by Pearson Education, Inc.

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Naming Ionic Compounds with Two Elements To name a compound that contains two elements,

• identify the cation •

and anion. name the cation first, followed by the name of the anion with an –ide ending.

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Charges of Representative Elements

Copyright © 2009 by Pearson Education, Inc.

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Names of Some Common Ions

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Learning Check Complete the names of the following ions: Ba2+ _________

Al3+ __________

K+ _________

N3 _________

O2 __________

F _________

P3 _________

S2 __________

Cl _________

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Solution Ba2+ barium

Al3+ aluminum

K+ potassium

N3 nitride

O2 oxide

F fluoride

P3 phosphide

S2 sulfide

Cl chloride

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Examples of Ionic Compounds with Two Elements Formula NaCl K2S MgO CaI2 Al2O3

Ions cation anion Na+ ClK+ S2Mg2+ O2Ca2+ IAl3+ O2-

Name sodium chloride potassium sulfide magnesium oxide calcium iodide aluminum oxide

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Learning Check Write the names of the following compounds: 1) CaO

___________

2) KBr

___________

3) Al2O3

___________

4) MgCl2

___________

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Solution Write the names of the following compounds: 1) CaO 2) KBr 3) Al2O3 4) MgCl2

calcium oxide potassium bromide aluminum oxide magnesium chloride

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Learning Check Write the formulas and names for compounds of the following ions: Br− S2− N3− Na+

Al3+

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Solution Br−

S2−

N3−

Na+

NaBr sodium bromide

Na2S sodium sulfide

Na3N sodium nitride

Al3+

AlBr3 aluminum bromide

Al2S3 aluminum sulfide

AlN aluminum nitride

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Transition Metals Form Positive Ions Most transition metals and Group 4 (14) metals form 2 or more positive ions. However, Zn2+, Ag+, and Cd2+ form only one ion.

Metals That Form More Than One Cation The name of metals

with two or more positive ions (cations) use a Roman numeral to identify ionic charge.

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Naming Ionic Compounds with Variable Charge Metals

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Naming Variable Charge Metals Transition metals with two different ions use a Roman numeral after the name of the metal to indicate ionic charge.

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Naming FeCl2 To name FeCl2: 1. Determine the charge of the cation using the charge of the anion (Cl-). Fe ion + 2 Cl- = Fe ion + 2- = 0 Fe ion = 2+ 2. Name the cation by the element name and add a Roman numeral in parentheses to show its charge. Fe2+ = iron(II) 3. Write the anion with an ide ending. FeCl2 = iron(II) chloride

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Naming Cr2O3 To name Cr2O3: 1. Determine the charge of cation from the anion (O2-). 2 Cr ions + 3 O2- = 0 2 Cr ions + 3 (2-) = 0 2 Cr ions - 6 = 0 2 Cr ions = 6+ Cr ion = 3+ = Cr3+ 2. Name the cation by the element name and add a Roman numeral in parentheses to show its charge. Cr3+ = chromium(III) 3. Write the anion with an ide ending. chromium(III) oxide = Cr2O3 17

Learning Check Select the correct name for each. A. Fe2S3 1) iron sulfide 2) iron(II) sulfide 3) iron(III) sulfide B. CuO 1) copper oxide 2) copper(I) oxide 3) copper(II) oxide

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Solution

Select the correct name for each. A. Fe2S3 3) iron (III) sulfide Fe3+ S2-

B. CuO 3) copper (II) oxide

Cu2+ O2-

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Guide to Writing Formulas from the Name

Copyright © 2009 by Pearson Education, Inc.

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Writing Formulas Write a formula for potassium sulfide. 1. Identify the cation and anion. potassium = K+ sulfide = S2− 2. Balance the charges. K+ S2− K+ 2(1+) + 2(1-) = 0

3. 2 K+ and 1 S2− =

K2S

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Writing Formulas Write a formula for iron(III) chloride. 1. Identify the cation and anion. iron (III) = Fe3+ (III = charge of 3+) chloride = Cl− 2. Balance the charges. Fe3+ Cl− Cl− = (3+) + 3(1-) = 0 Cl− 3. 1 Fe3+ and 3 Cl− = FeCl3

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Learning Check What is the correct formula for each of the following? A. Copper(I) nitride 1) CuN 2) CuN3 3) Cu3N B. Lead(IV) oxide 1) PbO2

2) PbO

3) Pb2O4

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Solution The correct formula is A. Copper(I) nitride 3) Cu3N

Need 3 Cu+ and N3-

B. Lead(IV) oxide 1) PbO2

Need Pb4+ and 2 O2-

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Formulas and Names of Inorganic Compounds Polyatomic Ions

Copyright © 2009 by Pearson Education, Inc.

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Polyatomic Ions A polyatomic ion • is a group of atoms. • has an overall ionic charge. Some examples of polyatomic ions are NH4+ ammonium OH− hydroxide NO3− nitrate NO2− nitrite CO32− carbonate PO43− phosphate HCO3− hydrogen carbonate (bicarbonate)

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Some Compounds with Polyatomic Ions

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Some Names of Polyatomic Ions The names of common polyatomic anions • end in ate. NO3− nitrate PO43− phosphate • with one oxygen less end in ite. NO2− nitrite PO33− phosphite • with hydrogen attached use the prefix hydrogen (or bi). HCO3− hydrogen carbonate (bicarbonate) HSO3− hydrogen sulfite (bisulfite)

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Names and Formulas of Common Polyatomic Ions

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Naming Compounds with Polyatomic Ions • The positive ion is named first, followed by the name of the polyatomic ion. NaNO3 sodium nitrate K2SO4 potassium sulfate Fe(HCO3)3 iron(III) bicarbonate or iron(III) hydrogen carbonate (NH4)3PO3 ammonium phosphite

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Guide to Naming Compounds with Polyatomic Ions

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Some Compounds with Polyatomic Ions

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Learning Check Match each formula with the correct name. A. MgS MgSO3 MgSO4

1) magnesium sulfite 2) magnesium sulfate 3) magnesium sulfide

B. Ca(ClO3)2 CaCl2 Ca(ClO2)2

1) calcium chlorate 2) calcium chlorite 3) calcium chloride

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Solution Match each formula with the correct name. A. MgS MgSO3 MgSO4

3) magnesium sulfide 1) magnesium sulfite 2) magnesium sulfate

B. Ca(ClO3)2 CaCl2 Ca(ClO2)2

1) calcium chlorate 3) calcium chloride 2) calcium chlorite

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Learning Check Name each of the following compounds: A. B. C. D. E.

Mg(NO3)2 Cu(ClO3)2 PbO2 Fe2(SO4)3 Ba3(PO3)2

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Solution Name each of the following compounds: A. B. C. D. E.

Mg(NO3)2 Cu(ClO3)2 PbO2 Fe2(SO4)3 Ba3(PO3)2

magnesium nitrate copper(II) chlorate lead(IV) oxide iron(III) sulfate barium phosphite

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Writing Formulas with Polyatomic Ions The formula of an ionic compound • containing a polyatomic ion must have a charge balance that equals zero (0). Na+ and NO3− -> NaNO3

• with two or more polyatomic ions has the polyatomic ions in parentheses. Mg2+ and 2NO3− -> Mg(NO3)2 subscript 2 for charge balance

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Learning Check Select the correct formula for each. A. aluminum nitrate 1) AlNO3 2) Al(NO)3 B. copper(II) nitrate 1) CuNO3 2) Cu(NO3)2 C. iron(III) hydroxide 1) FeOH 2) Fe3OH D. tin(IV) hydroxide 1) Sn(OH)4 2) Sn(OH)2

3) Al(NO3)3

3) Cu2(NO3) 3) Fe(OH)3 3) Sn4(OH)

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Solution Select the correct formula for each. A. aluminum nitrate B. copper(II) nitrate C. iron(III) hydroxide D. tin(IV) hydroxide

3) Al(NO3)3 2) Cu(NO3)2 3) Fe(OH)3 1) Sn(OH)4

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Learning Check Write the correct formula for each. A. B. C. D. E.

potassium bromate calcium carbonate sodium phosphate iron(III) oxide iron(II) nitrite

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Solution Write the correct formula for each. A.

potassium bromate

KBrO3

B.

calcium carbonate

CaCO3

C.

sodium phosphate

Na3PO4

D.

iron(III) oxide

Fe2O3

E.

iron(II) nitrite

Fe(NO2)2

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Flowchart for Naming Ionic Compounds

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Learning Check Name the following compounds: A. Ca3(PO4)2 B. FeBr3 C. Al2S3

D. Zn(NO2)2 E. NaHCO3

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Solution Name the following compounds: A. Ca3(PO4)2Ca2+ PO43− calcium phosphate B. FeBr3

Fe3+ Br −

iron(III) bromide

C. Al2S3

Al3+ S2−

aluminum sulfide

D. Zn(NO2)2

Zn2+ NO2−

zinc nitrite

E. NaHCO3

Na+ HCO3− sodium hydrogen carbonate or sodium bicarbonate

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Learning Check Write the formulas for the following: A. calcium nitrate B. iron(II) hydroxide C. aluminum carbonate

D. copper(II) bromide E. lithium phosphate

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Solution Write the formulas for the following: A. calcium nitrate Ca2+, NO3−

Ca(NO3)2

B. iron(II) hydroxide

Fe2+, OH−

Fe(OH)2

C. aluminum carbonate

Al3+, CO32−

Al2(CO3)3

D. copper(II) bromide

Cu2+, Br−

CuBr2

E. lithium phosphate

Li+, PO43−

Li3PO4

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Naming Covalent Compounds In the names of covalent compounds, prefixes are used to indicate the number of atoms (subscript) of each element. (mono is usually omitted)

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Guide to Naming Covalent Compounds

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Naming Covalent Compounds What is the name of SO3? 1. The first nonmetal is S sulfur. 2. The second nonmetal is O, named oxide. 3. The subscript 3 of O is shown as the prefix tri. SO3 -> sulfur trioxide

The subscript 1 (for S) or mono is understood.

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Naming Covalent Compounds Name P4S3. 1. The first nonmetal, P, is phosphorus. 2. The second nonmetal, S, is sulfide. 3. The subscript 4 of P is shown as tetra. The subscript 3 of O is shown as tri. P4S3 -> tetraphosphorus trisulfide

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Formulas and Names of Some Covalent Compounds

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Learning Check Select the correct name for each compound.

A.

SiCl4

1) silicon chloride 2) tetrasilicon chloride 3) silicon tetrachloride

B.

P2O5

1) phosphorus oxide 2) phosphorus pentoxide 3) diphosphorus pentoxide

C.

Cl2O7

1) dichlorine heptoxide 2) dichlorine oxide 3) chlorine heptoxide

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Solution Select the correct name for each compound. A. B. C.

SiCl4 P2O5 Cl2O7

3) silicon tetrachloride 3) diphosphorus pentoxide 1) dichlorine heptoxide

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Learning Check Write the name of each covalent compound. CO CO2 PCl3 CCl4 N2O

_____________________ _____________________ _____________________ _____________________ _____________________

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Solution Write the name of each covalent compound. CO CO2 PCl3 CCl4 N2O

carbon monoxide carbon dioxide phosphorus trichloride carbon tetrachloride dinitrogen oxide

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Guide to Writing Formulas for Covalent Compounds

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Example: Writing Formulas for Covalent Compounds Write the formula for carbon disulfide. STEP 1:

Elements are C and S

STEP 2:

No prefix for carbon means 1 C Prefix di = 2 Formula: CS2

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Learning Check Write the correct formula for each of the following: A. phosphorus pentachloride

B. dinitrogen trioxide C. sulfur hexafluoride

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Solution Write the correct formula for each of the following: A. phosphorus pentachloride 1P

penta = 5 Cl

PCl5

B. dinitrogen trioxide di = 2 N tri = 3 O

N2O3

C. sulfur hexafluoride 1S

hexa = 6 F

SF6 59

Learning Check Identify each compound as ionic or covalent, and give its correct name. A. B. C. D. E.

SO3 BaCl2 (NH4)3PO3 Cu2CO3 N 2O 4

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Study Tip: Ionic or Covalent A compound is • ionic if the first element in the formula or the name is a metal or the polyatomic ion NH4+ . K2O K is a metal; compound is ionic; potassium oxide • covalent if the first element in the formula or the name is a nonmetal.

N2O N is a nonmetal; compound is covalent; dinitrogen oxide 61

Solution Identify each compound as ionic or covalent and give its correct name. A. B. C. D. E.

SO3 BaCl2 (NH4)3PO3 Cu2CO3 N 2O 4

covalent – sulfur trioxide ionic – barium chloride ionic – ammonium phosphite ionic – copper(I) carbonate covalent – dinitrogen tetroxide

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Learning Check Identify each compound as ionic or covalent and give its correct name. A. Ca3(PO4)2 B. FeBr3 C. SCl2 D. Cl2O E. N2

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Solution Identify each compound as ionic or covalent and give its correct name. A. Ca3(PO4) ionic

Ca2+ PO43−

calcium phosphate

B. FeBr3

ionic

Fe3+ Br −

iron(III) bromide

C. SCl2

covalent

1S 2 Cl

sulfur dichloride

D. Cl2O

covalent

2 Cl 1 O

dichlorine oxide

E. N2

covalent

element

nitrogen

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Learning Check Determine if each is ionic (I) or covalent (C ), and write the formula. A. calcium nitrate B. boron trifluoride C. aluminum carbonate D. dinitrogen tetroxide

E. copper(I) phosphate

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Solution Determine if each is ionic (I) or covalent (C ), and write the formula. A. calcium nitrate

(I)

Ca2+, NO3−

Ca(NO3)2

B. boron trifluoride

(C)

1 B, 3 F

BF3

C. aluminum carbonate (I) Al3+, CO32−

Al2(CO3) 3

D. dinitrogen tetroxide (C) 2 N, 4 O

N2O4

E. copper(I) phosphate (I) Cu+, PO43−

Cu3PO4

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Acids An acid can be defined as a substance that yields hydrogen ions (H+) when dissolved in water. HCl •Pure substance, hydrogen chloride •Dissolved in water (H+ Cl-), hydrochloric acid

An oxoacid is an acid that contains hydrogen, oxygen, and another element. HNO3

nitric acid

H2CO3

carbonic acid

H2SO4

sulfuric acid HNO3

Acids

Acids

Bases A base can be defined as a substance that yields hydroxide ions (OH-) when dissolved in water.

NaOH

sodium hydroxide

KOH

potassium hydroxide

Ba(OH)2

barium hydroxide

Hydrates Hydrates are compounds that have a specific number of water molecules attached to them. BaCl2•2H2O

barium chloride dihydrate

LiCl•H2O

lithium chloride monohydrate

MgSO4•7H2O

magnesium sulfate heptahydrate

Sr(NO3)2 •4H2O

strontium nitrate tetrahydrate

CuSO4•5H2O

CuSO4