Names & Formulas of Ionic Compounds

Ionic compounds are named using the names of the ions that compose them.

To name an ionic compound:

Cation name followed by anion name

Learn the names and formulas of the ions in your syllabus.The following slides explain the

systematic way that ions are named.

Naming Cations

Cations formed from metal ions have the same name as the metal.

K+ potassium ionCa2+ calcium ionAl3+ aluminum ion

Naming Cations

Cations with varying charges

the charge of the specific cation is given by Roman numeral in parentheses after the name of the metal

Fe2+ iron (II) ionFe3+ iron (III) ionCu+ copper (I) ionCu2+ copper (II) ion

Naming Cations

One common polyatomic cation found in ionic compounds

NH4+ ammonium ion

Note: Compounds whose formulas start with NH4 are ionic even though they are composed only of non-metals.

Naming Anions

Monoatomic anions

drop the ending of the element’s nameadd “ide”

N nitrogen O oxygen

N3- O2-nitride oxide

Naming Anions

Some simple polyatomic anions use the “ide” ending as well

OH- hydroxideCN- cyanideO2

2- peroxide

Naming Oxyanions

Oxyanions (polyatomic anions containing oxygen) have names ending in:“ate” most common

oxyanionof the element

“ite” same charge, 1 less oxygen

NO3- nitrate SO4

2- sulfateNO2

- nitrite SO32- sulfite

CO32- carbonate PO4

3- phosphatePO3

3- phosphite

Oxyanions (cont.)

Some elements like the halogens can form more than two oxyanions:

“per” 1 more O than the “ate” oxyanion“hypo” 1 less O than the “ite” oxyanion

ClO4- perchlorate

ClO3- chlorate

ClO2- chlorite

ClO- hypochlorite

Oxyanions Anions derived by adding H+ to an oxyanion:

add “hydrogen” or “dihydrogen” as prefix to oxyanion name

CO32- carbonate

HCO3- hydrogen carbonate

(usually called bicarbonate)

PO43- phosphate

H2 PO4- dihydrogen phosphate

Naming Ionic Compounds

Name ionic compounds using cation name followed by anion name

NaCl sodium chlorideCaBr2 calcium bromideNaClO sodium hypochlorite

Cu(NO3)2 copper (II) nitrate

Naming Ionic Compounds

Example: Write the names of these ionic compounds.

Na2OFeCl3

(NH4)3PO4

KClO4

SnO2

Cu(NO3)2

Writing Formulas from Names

Given the name of a compound, you must be able to write its formula.Identify the symbol and charge for each

ion.

Determine the correct number of each ion needed to balance the charges (write an electrically neutral formula).

Writing Formulas from Names

Example: Write the empirical formula for ammonium sulfate

(NH4)2SO4

ammonium

sulfate

NH4+

SO42-

SO42-

NH4+

NH4+

Writing Formulas from Names

Example: Write the formulas for these ionic compounds

lithium chloridebarium nitratesodium perchlorateiron(III) oxidesodium hydrogen phosphateLead (IV) sulfate

Names & Formulas of Acids

Acid: a substance whose molecules form H+ ions when dissolved in waterHCl (aq)HCN (g)HClO3 (aq)

Name of acid depends on:Type of acid

Oxygen present or notPure or aqueous

Name of anion

Names & Formulas of Acids

Three naming systems for acids:

Oxyanion-based acids (with oxygen)

Acids with “ide” anions (no oxygen)aqueous solutionsgases

Oxyanion Based Acids

If the acid contains oxygen, identify the anion and write its name

Change the ending of the anion name:

“ite” “ous acid”“ate” “ic acid”

HClO4 perchlorate perchloric acidHClO2 chlorite chlorous acid

Oxyanion Based Acids

Naming acids derived from oxyanions of S and P:H2SO4 :

oxyanion = sulfateSulfic acid Sulfuric acid

H3PO4 :oxyanion = phosphatePhosphic acid Phosphoric acid

Acids Without Oxyanions

If the acid does not contain oxygen and is dissolved in water (aq):

hydro + (anion name minus “ide”) + “ic acid”

HCl (aq) hydro + chloride + ic acid

hydrochloric acid“Hydro” = no oxygen and (aq)

Acids Without Oxyanions

If the acid does not contain oxygen and is a gas (g):

name the acid as an ionic compound:hydrogen followed by anion name

HCl (g) hydrogen chloride

“Hydrogen” = no oxygen and (g)

Naming Acids

To name an acid:Does it have oxygen?

YesWrite name of anionChange “ate” to “ic acid”Change “ite” to “ous acid”

If no oxygen, is it (aq)?Yes

Start with hydroAdd the name of anionChange “ide” to “ic acid”

Naming Acids

If no oxygen, is it (g)?Yes

Start with hydrogenAdd the name of the anion

Naming Acids

Example: Name the following acids.

HNO3

HBr (aq)

H2S (g)

Writing Formulas from Acid Names To write the formula of an acid starting with the

name of the acid, first decide which category of acid it is:Oxyanion based No oxygen, (aq) (begins with “hydro”)No oxygen, (g) (begins with

“hydrogen”)

Write the formula for the anion (including charge).

Add enough H+ ions to make a neutral compound.

Writing Formulas from Acid Names

Example: Write the formula for perchloric acid.

Category: oxyanion containing acid

Anion: perchloric acid perchlorate (ClO4-)

Formula: HClO4

ClO4-H+

Writing Formulas from Acid Names

Example: Write the formula for each of the following acids.

Phosphoric acid:

Hydrobromic acid:

Hydrogen cyanide:

Naming Acids

You must know the names and formulas for the following acids:

HF (aq) hydrofluoric acidHCl (aq) hydrochloric acidHBr (aq) hydrobromic acidHI (aq) hydroiodic acidHClO4 perchloric acidHClO3 chloric acidH2SO4 sulfuric acidHNO3 nitric acid

Naming Acids

You must know the names and formulas for the following acids:

H3PO4 phosphoric acidHC2H3O2 acetic acidH2CO3 carbonic acidH2S (g) hydrogen sulfideHCN (g) hydrogen cyanide

Binary Molecular Compounds

Binary molecular compound: compound composed of molecules with two different types of atoms

Remember: Many molecular compounds are composed strictly of non-metals.

SO2 N2O4

H2O PCl5

P4O10 CO

Binary Molecular Compounds

The names of binary molecular compounds give both the type and number of each type of atom present.

The general pattern for naming binary molecular compounds is:

prefixprefix element name element name prefixprefix element name with ide ending element name with ide ending

Binary Molecular Compounds

The first element is named using the name of the element.

The second element is named using the “ide” ending.

Greek prefixes are used to indicate the number of each type of element present.

prefixprefix element name element name prefixprefix element name with ide ending element name with ide ending

Greek Prefixes

Prefix Meaningmono 1di 2tri 3tetra 4penta 5hexa 6hepta 7octa 8nona 9deca 10

You must know these!!

P4S10 =

tetraphosphorus decasulfide

Binary Molecular Compounds

Special conventions for using Greek prefixes:Mono is never used with the first

element

The “a” or “o” in the prefix is dropped if the name of the element begins with a vowel.

CO: carbon monooxide carbon monoxide

Binary Molecular Compounds

Example: Name the following compounds.

N2O4

PCl5

Cl2O7

Binary Molecular Compounds

Example: Write the formulas for the following compounds.

tetraphosphorus decoxide

sulfur trioxide

disulfur dichloride

Naming — Revisited

Before you can correctly name a compound or write its formula, YOU MUST determine which type of compound it is:

Ionic starts with a metal or NH4

Acid starts with H or HnBinary Molecular two non-metals

THEN use the appropriate naming system or method to write the formula.

Simple Organic Compounds

Organic compounds: compounds that contain carbon and

hydrogen, often in combination with oxygen or nitrogen.

Simple Organic Compounds

You must know the names and structural formulas of the following simple organic compounds:MethanePropaneMethanolEthanolAcetic acidAcetone

Simple Organic Compounds

Methane:

Ethane:

CH

HH

H

CH

H

H

C

H

H

H

Methanol:

Ethanol:

CH

H

H

C

H

H

OH

C

H

H

H

H

C

H

H

OH

C

H

H

OH

Simple Organic Compounds

Propane:

Acetic Acid:

C

H

H

H

H

C

H

H

C

H

H

OH

C

H

H

H

C

H

H

H

H

C

H

H

C

H

H

C

H

H

H

C

O

OH

Acetone:

C

H

H

H

H

C

C

H

H

C

H

H

H

C

O

OH

O

Common “Household” Chemicals

You are responsible for knowing the names and formulas for the chemical present in:Water (H2O)Ammonia (NH3)Baking soda

sodium bicarbonateNaHCO3

Natural gasMethaneCH4

VinegarAcetic acidHC2H3O2 (structure on previous slide)

Common “Household” Chemicals

You are responsible for knowing the names and formulas for the chemical present in:Table salt

Sodium chlorideNaCl

BleachSodium hypochloriteNaClO

Hydrogen peroxideH2O2

Common “Household” Chemicals

You are responsible for knowing the names and formulas for the chemical present in:Drinking alcohol

EthanolC2H5OH

Rubbing alcoholIsopropyl alcohol

Nail polish removerAcetone

CH

H

H

C

H

H

OH

C

H

H

H

H

C

C

H

H

C

H

H

H

C

O

OH

OH

H C C C HH OH

HHH

H