Ionic Compound FormulasIonic Compound Formulas

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IonsIonsIonsIons

Cation: A positive ionCation: A positive ionMgMg2+2+, NH, NH44

++

Anion: A negative ionAnion: A negative ionClCl, SO, SO44

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Cation: A positive ionCation: A positive ionMgMg2+2+, NH, NH44

++

Anion: A negative ionAnion: A negative ionClCl, SO, SO44

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Predicting Ionic ChargesPredicting Ionic Charges

Group 1Group 1::Lose 1 electron to form Lose 1 electron to form 1+1+ ions ions

HH++ LiLi++ NaNa++ KK++

Predicting Ionic ChargesPredicting Ionic Charges

Group 2Group 2::Loses 2 electrons to form Loses 2 electrons to form 2+2+ ions ions

BeBe2+2+ MgMg2+2+ CaCa2+2+ SrSr2+2+ BaBa2+2+

Predicting Ionic ChargesPredicting Ionic ChargesGroup 13Group 13:: Loses 3 Loses 3 electrons to form electrons to form 3+3+ ions ions

BB3+3+ AlAl3+3+ GaGa3+3+

Predicting Ionic ChargesPredicting Ionic ChargesGroup 14Group 14:: Lose 4 Lose 4 electrons or gain electrons or gain 4 electrons?4 electrons?

Neither!Neither! Group 13 Group 13 elements rarely elements rarely form ions.form ions.

Predicting Ionic ChargesPredicting Ionic ChargesGroup 15Group 15:: Gains 3 Gains 3 electrons to form electrons to form 3-3- ions ions

NN3-3-

PP3-3-

AsAs3-3-

NitridePhosphide

Arsenide

Predicting Ionic ChargesPredicting Ionic ChargesGroup 16Group 16:: Gains 2 Gains 2 electrons to form electrons to form 2-2- ions ions

OO2-2-

SS2-2-

SeSe2-2-

Oxide

SulfideSelenide

Predicting Ionic ChargesPredicting Ionic ChargesGroup Group 1717:: Gains 1 Gains 1 electron to form electron to form 1-1- ions ions

FF1-1-

ClCl1-1-

BrBr1-1-

Fluoride

Chloride

Bromide

II1-1- Iodide

Predicting Ionic ChargesPredicting Ionic ChargesGroup 18Group 18:: Stable Stable Noble gases Noble gases do do notnot form ions! form ions!

Predicting Ionic ChargesPredicting Ionic ChargesGroups 3 - Groups 3 - 1212::

Many transition elements Many transition elements have more than one possible oxidation have more than one possible oxidation state.state.Iron(II) = Fe2+ Iron(III) = Fe3+

Predicting Ionic ChargesPredicting Ionic ChargesGroups 3 - Groups 3 - 1212::

Some Some transitiontransition elements elements have only one possible oxidation state.have only one possible oxidation state.

Zinc = Zn2+ Silver = Ag+

Writing Ionic Compound Writing Ionic Compound FormulasFormulas

Example: Barium nitrate

1. Write the formulas for the cation and anion, including CHARGES!

BaBa2+2+ NONO33--

2. Check to see if charges are balanced.

3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

Not balanced!

( )( ) 22

Writing Ionic Compound Writing Ionic Compound FormulasFormulas

Example: Ammonium sulfate

1. Write the formulas for the cation and anion, including CHARGES!

NHNH44++ SOSO44

2-2-

2. Check to see if charges are balanced.

3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

Not balanced!

( )( )22

Writing Ionic Compound Writing Ionic Compound FormulasFormulas

Example: Iron(III) chloride

1. Write the formulas for the cation and anion, including CHARGES!

FeFe3+3+ ClCl--

2. Check to see if charges are balanced.

3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

Not balanced!

33

Writing Ionic Compound Writing Ionic Compound FormulasFormulas

Example: Aluminum sulfide

1. Write the formulas for the cation and anion, including CHARGES!

AlAl3+3+ SS2-2-

2. Check to see if charges are balanced.

3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

Not balanced!

22 33

Writing Ionic Compound Writing Ionic Compound FormulasFormulas

Example: Magnesium carbonate

1. Write the formulas for the cation and anion, including CHARGES!

MgMg2+2+ COCO332-2-

2. Check to see if charges are balanced.

They are balanced!

Writing Ionic Compound Writing Ionic Compound FormulasFormulas

Example: Zinc hydroxide

1. Write the formulas for the cation and anion, including CHARGES!

ZnZn2+2+ OHOH--

2. Check to see if charges are balanced.

3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

Not balanced!

( )( )22

Writing Ionic Compound Writing Ionic Compound FormulasFormulas

Example: Aluminum phosphate

1. Write the formulas for the cation and anion, including CHARGES!

AlAl3+3+ POPO443-3-

2. Check to see if charges are balanced.

They ARE balanced!

Naming Ionic CompoundsNaming Ionic CompoundsNaming Ionic CompoundsNaming Ionic CompoundsCation first, then anionCation first, then anion

Monatomic cation = name of the Monatomic cation = name of the elementelement

CaCa2+2+ = calcium ion = calcium ion

Monatomic anionMonatomic anion == rootroot + + -ide-ideClCl == chlorchlorideide

CaClCaCl22 = calcium chloride = calcium chloride

Cation first, then anionCation first, then anion

Monatomic cation = name of the Monatomic cation = name of the elementelement

CaCa2+2+ = calcium ion = calcium ion

Monatomic anionMonatomic anion == rootroot + + -ide-ideClCl == chlorchlorideide

CaClCaCl22 = calcium chloride = calcium chloride

Naming Ionic CompoundsNaming Ionic Compounds(continued)(continued)

Naming Ionic CompoundsNaming Ionic Compounds(continued)(continued)

some metal forms more than one cationsome metal forms more than one cation use use Roman numeral Roman numeral in namein name

PbClPbCl22

PbPb2+2+ is cation is cation

PbClPbCl22 = lead(II) chloride = lead(II) chloride

some metal forms more than one cationsome metal forms more than one cation use use Roman numeral Roman numeral in namein name

PbClPbCl22

PbPb2+2+ is cation is cation

PbClPbCl22 = lead(II) chloride = lead(II) chloride

Metals with multiple oxidation Metals with multiple oxidation statesstates