Ionic Compounds

Ionic CompoundsIonic Compounds

OutlineOutline



Ionic compounds are made up of positive Ionic compounds are made up of positive and negative ions.and negative ions.

These ions result from the transfer of These ions result from the transfer of electrons from a metal to a non-metal.electrons from a metal to a non-metal.

The positive and negative ions are The positive and negative ions are attracted to each other because they attracted to each other because they have opposite charges.have opposite charges.


Calcium transfers two electrons, one to each fluorine atom

All three ions are stable (max. # of electrons in valence shell.)

Chemical FormulasChemical Formulas

Are a combination of element symbols Are a combination of element symbols and subscripts that represents a and subscripts that represents a particular compound.particular compound.

Element symbolElement symbol

Eg. CEg. C22HH44OO66

Subscripts Subscripts (indicate the (indicate the number of number of ions of ions of each type.) each type.)

Naming Ionic CompoundsNaming Ionic Compounds

The name of the metal is first.The name of the metal is first.

The name of the non-metal is second.The name of the non-metal is second.

But – the ending of the non-metal But – the ending of the non-metal changes to “ide”changes to “ide”

Eg. The compound formed by calcium Eg. The compound formed by calcium and iodine = calcium iodand iodine = calcium iodideide

How to Write the Chemical How to Write the Chemical Formula for Ionic CompoundsFormula for Ionic Compounds

Eg. Eg. Ionic Compound formed by calcium Ionic Compound formed by calcium and fluorineand fluorine

Step 1. Step 1. Write the Write the symbolssymbols, with the , with the metal metal first.first.

Ca F Ca F


Step 2. Step 2. Write the Write the ionicionic chargecharge above above each each symbolsymbol to indicate the to indicate the stable ionstable ion that each element that each element forms.forms.

2+2+ 1-1-

Ca FCa F


Step 3. Step 3. CrisscrossCrisscross the the ionic chargesionic charges to to produce produce subscriptssubscripts..

2+2+ 1-1-

Ca FCa F


Step 4. Step 4. Write the formula using Write the formula using subscriptssubscripts to indicate the to indicate the number of ionsnumber of ions of of each each type. Reduce the number of type. Reduce the number of subscriptssubscripts if if possible.possible.

CaCa11FF22

Reduced:Reduced: CaFCaF22

Name of Compound: Calcium fluorName of Compound: Calcium fluorideide


Eg. Ionic compound formed by aluminum and Eg. Ionic compound formed by aluminum and sulfursulfur

Steps 1-3:Steps 1-3:3+3+ 2-2-Al SAl S

Step 4: AlStep 4: Al22SS33

Name of compound: Aluminum SulfName of compound: Aluminum Sulfideide


Eg. Ionic compound formed by magnesium and Eg. Ionic compound formed by magnesium and oxygen.oxygen.

Steps 1-3:Steps 1-3:

2+2+ 2-2-

Mg OMg O

Step 4: MgStep 4: Mg22OO22 Reduce: MgO Reduce: MgO

Name of compound: Magnesium OxName of compound: Magnesium Oxideide

Multivalent Metal ElementsMultivalent Metal Elements

Some metals form more than Some metals form more than one kind of ion.one kind of ion.

A Roman numeral is added to A Roman numeral is added to the metal name to indicate its the metal name to indicate its ionic charge.ionic charge.

Multiple Ionic ChargesMultiple Ionic Charges

NameName SymbolSymbol Ionic Ionic ChargeCharge

Roman Roman NumeralNumeral

CopperCopper CuCu 1+1+

2+2+II

IIII

IronIron FeFe 2+2+

3+3+IIII

IIIIII

LeadLead PbPb 2+2+

4+4+IIII

IVIV

TinTin SnSn 2+2+

4+4+IIII

IVIV


Going from formula to name:Going from formula to name:

1.1. Metal name unchangedMetal name unchanged2.2. Find the charge on the metal using Find the charge on the metal using

reverse crossoverreverse crossover3.3. Add the metal’s change using roman Add the metal’s change using roman

numbers (I, II, III, IV, etc..)numbers (I, II, III, IV, etc..)4.4. Non metal name with ‘ide’ endingNon metal name with ‘ide’ ending

*Be sure to watch for compounds that *Be sure to watch for compounds that have already been reduced*have already been reduced*

eg. eg. – CuCl CuCl copper (I) chloride copper (I) chloride

– CuClCuCl22 copper (II) chloride copper (II) chloride


Going from name to formula:Going from name to formula:

1.1. Write each element’s symbol and charges. (For Write each element’s symbol and charges. (For metal use number in roman numerals as the metal use number in roman numerals as the charge).charge).

2.2. Crossover and simplify when needed.Crossover and simplify when needed.

eg. eg. – copper (I) chloride copper (I) chloride CuCl CuCl

– copper (II) chloride copper (II) chloride CuCl CuCl22

Classical (Alchemist) Method:Classical (Alchemist) Method:

Suffix added to ‘root’ name (must Suffix added to ‘root’ name (must memorize)memorize)

Suffix: Suffix: higher charge (‘ic’)higher charge (‘ic’)

lower charge (‘ous’)lower charge (‘ous’)

Eg. Eg. Cupric oxide (copper with charge of Cupric oxide (copper with charge of +2)+2)

plumbous chloride (lead with charge plumbous chloride (lead with charge of of +2)+2)

Ionic Compounds

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