Formulas and Names-Inorganic Compounds

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Formulas and Names of

Inorganic Compounds

Naming and Writing Ionic

Formulas

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.

Charges of Representative

Elements

Names of Some Common Ions

Complete the names of the following ions:

Ba2+ Al3+ K+

_________ __________ _________

N3 O2 F

_________ __________ _________

P3 S2 Cl

_________ __________ _________

Learning Check

Ba2+ Al3+ K+

barium aluminum potassium

N3 O2 F

nitride oxide fluoride

P3 S2 Cl

phosphide sulfide chloride

Solution

Formula Ions Name cation anion NaCl Na+ Cl- sodium chloride

K2S K+ S2- potassium sulfide

MgO Mg2+ O2- magnesium oxide

CaI2 Ca2+ I- calcium iodide

Al2O3 Al3+ O2- aluminum oxide

Examples of Ionic Compounds with

Two Elements

Write the names of the following compounds: 1) CaO ___________

2) KBr ___________

3) Al2O3 ___________

4) MgCl2 ___________

Learning Check

Write the names of the following compounds:

1) CaO calcium oxide

2) KBr potassium bromide

3) Al2O3 aluminum oxide

4) MgCl2 magnesium chloride

Solution

Learning Check

Write the formulas and names for compounds of the

following ions: Br− S2− N3− Na+

Solution

Br− S2− N3−

sodium

bromide

sodium

sulfide

sodium

nitride

aluminum

bromide

aluminum

sulfide

aluminum

nitride

Transition Metals Form Positive

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.

Naming Ionic Compounds with

Variable Charge Metals

Naming Variable Charge Metals

Transition metals with two different ions use a Roman

numeral after the name of the metal to indicate ionic

charge.

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

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

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

Solution

Select the correct name for each.

A. Fe2S3

3) iron (III) sulfide Fe3+ S2-

B. CuO

3) copper (II) oxide Cu2+ O2-

Guide to Writing Formulas from the

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

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

3. 1 Fe3+ and 3 Cl− = FeCl3

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

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-

Polyatomic Ions

Formulas and Names of

Inorganic Compounds

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 PO4

3− phosphate

HCO3− hydrogen carbonate

(bicarbonate)

Polyatomic Ions

Some Compounds with Polyatomic

The names of common polyatomic anions

• end in ate.

NO3− nitrate PO4

3− phosphate

• with one oxygen less end in ite.

NO2− nitrite PO3

3− phosphite

• with hydrogen attached use the prefix hydrogen (or bi).

HCO3− hydrogen carbonate (bicarbonate)

HSO3− hydrogen sulfite (bisulfite)

Some Names of Polyatomic Ions

Names and Formulas of Common

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

Naming Compounds with

Polyatomic Ions

Guide to Naming Compounds with

Polyatomic Ions

Some Compounds with Polyatomic

Match each formula with the correct name.

A. MgS 1) magnesium sulfite

MgSO3 2) magnesium sulfate

MgSO4 3) magnesium sulfide

B. Ca(ClO3)2 1) calcium chlorate

CaCl2 2) calcium chlorite

Ca(ClO2)2 3) calcium chloride

Learning Check

Match each formula with the correct name.

A. MgS 3) magnesium sulfide

MgSO3 1) magnesium sulfite

MgSO4 2) magnesium sulfate

B. Ca(ClO3)2 1) calcium chlorate

CaCl2 3) calcium chloride

Ca(ClO2)2 2) calcium chlorite

Solution

Learning Check

Name each of the following compounds:

A. Mg(NO3)2

B. Cu(ClO3)2

C. PbO2

D. Fe2(SO4)3

E. Ba3(PO3)2

Solution

Name each of the following compounds:

A. Mg(NO3)2 magnesium nitrate

B. Cu(ClO3)2 copper(II) chlorate

C. PbO2 lead(IV) oxide

D. Fe2(SO4)3 iron(III) sulfate

E. Ba3(PO3)2 barium phosphite

Writing Formulas with Polyatomic

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

Select the correct formula for each.

A. aluminum nitrate

1) AlNO3 2) Al(NO)3 3) Al(NO3)3

B. copper(II) nitrate

1) CuNO3 2) Cu(NO3)2 3) Cu2(NO3)

C. iron(III) hydroxide

1) FeOH 2) Fe3OH 3) Fe(OH)3

D. tin(IV) hydroxide

1) Sn(OH)4 2) Sn(OH)2 3) Sn4(OH)

Learning Check

Select the correct formula for each.

A. aluminum nitrate 3) Al(NO3)3

B. copper(II) nitrate 2) Cu(NO3)2

C. iron(III) hydroxide 3) Fe(OH)3

D. tin(IV) hydroxide 1) Sn(OH)4

Solution

Learning Check

Write the correct formula for each.

A. potassium bromate

B. calcium carbonate

C. sodium phosphate

D. iron(III) oxide

E. iron(II) nitrite

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

Flowchart for Naming Ionic

Compounds

Learning Check

Name the following compounds:

A. Ca3(PO4)2

B. FeBr3

C. Al2S3

D. Zn(NO2)2

E. NaHCO3

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

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

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

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)

Guide to 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.

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

Formulas and Names of Some

Covalent Compounds

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

Learning Check

Select the correct name for each compound.

A. SiCl4 3) silicon tetrachloride

B. P2O5 3) diphosphorus pentoxide

C. Cl2O7 1) dichlorine heptoxide

Solution

Write the name of each covalent compound.

CO _____________________

CO2 _____________________

PCl3 _____________________

CCl4 _____________________

N2O _____________________

Learning Check

Write the name of each covalent compound.

CO carbon monoxide

CO2 carbon dioxide

PCl3 phosphorus trichloride

CCl4 carbon tetrachloride

N2O dinitrogen oxide

Solution

Guide to 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

Example: Writing Formulas for

Covalent Compounds

Write the correct formula for each of the following:

A. phosphorus pentachloride

B. dinitrogen trioxide

C. sulfur hexafluoride

Learning Check

Write the correct formula for each of the following:

A. phosphorus pentachloride

1 P penta = 5 Cl PCl5

B. dinitrogen trioxide

di = 2 N tri = 3 O N2O3

C. sulfur hexafluoride

1 S hexa = 6 F SF6

Solution

Learning Check

Identify each compound as ionic or covalent, and give its

correct name.

A. SO3

B. BaCl2

C. (NH4)3PO3

D. Cu2CO3

E. N2O4

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

Solution

Identify each compound as ionic or covalent and give its

correct name.

A. SO3 covalent – sulfur trioxide

B. BaCl2 ionic – barium chloride

C. (NH4)3PO3 ionic – ammonium phosphite

D. Cu2CO3 ionic – copper(I) carbonate

E. N2O4 covalent – dinitrogen tetroxide

Learning Check

correct name.

A. Ca3(PO4)2

B. FeBr3

C. SCl2

D. Cl2O

Solution

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

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

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

An acid can be defined as a substance that yields

hydrogen ions (H+) when dissolved in water.

•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

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 are compounds that have a specific number

of water molecules attached to them.

BaCl2•2H2O

LiCl•H2O

MgSO4•7H2O

Sr(NO3)2 •4H2O

barium chloride dihydrate

lithium chloride monohydrate

magnesium sulfate heptahydrate

strontium nitrate tetrahydrate

CuSO4•5H2O CuSO4

Hydrates

Formulas and Names-Inorganic Compounds

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