Formula Writing Formula Writing and Nomenclatureand Nomenclature

What is an ion?What is an ion?

An ion is a ______________.An ion is a ______________. It may be a ____ or ___charge.It may be a ____ or ___charge.

Lose electrons Lose electrons cation (+) cation (+) Gain electrons Gain electrons anion (-) anion (-)

charged particle.

+ -

Why do atoms gain or lose Why do atoms gain or lose electrons?electrons?

To become more ______.To become more ______.

Electrons come from ___________.Electrons come from ___________.

One ion ______ e- and the other One ion ______ e- and the other _____e- to form a _____._____e- to form a _____.

stable

other atoms

gains

loses

bond

Do ions follow rules? YES!Do ions follow rules? YES!

Octet Rule: _____________Octet Rule: _____________

Tendency of valence electrons to Tendency of valence electrons to rearrange to form a ________________ .rearrange to form a ________________ .

THE MAGIC NUMBER=________THE MAGIC NUMBER=________

The Rule of 8The Rule of 8

stable/full valence shell

HappyHappy Ion

Examples:Examples:

Na 2-8Na 2-8

F 2-7F 2-7

-1+1

8-1

Opposites attract! NaF

Do ions follow rules? YES!Do ions follow rules? YES!

Duet Rule:___________Duet Rule:___________ For atoms so small their valence shell is For atoms so small their valence shell is

the ______ energy level which can only the ______ energy level which can only hold ___________. hold ___________.

The Rule of 2The Rule of 2

first

two electrons

Examples:Examples:

H can gain ___ e- to form _____.H can gain ___ e- to form _____. H can lose ____ e- to form_____.H can lose ____ e- to form_____. Li loses _____ e- to form _____.Li loses _____ e- to form _____. Be loses ____ e- to form _____.Be loses ____ e- to form _____. B loses _____ e- to form _____. B loses _____ e- to form _____.

1

1

1

2

3

H-1

H+1

Li+1

Be+2

B+3

Writing FormulasWriting Formulas

All compounds have a charge of All compounds have a charge of zero.zero. When writing formulas, all ions have to When writing formulas, all ions have to

add up to add up to zero.zero.

IUPACIUPAC

IUPAC- International Union of Pure and IUPAC- International Union of Pure and Applied Chemists (created this naming Applied Chemists (created this naming system)system)

Forming Binary Ionic Forming Binary Ionic CompoundsCompounds

Binary = two elementsBinary = two elements Ionic = one metal and one nonmetalIonic = one metal and one nonmetal Transfer of electronsTransfer of electrons Not called molecules!Not called molecules!

Writing Binary IonicsWriting Binary Ionics

Write each ion (metal first)Write each ion (metal first) Crisscross the chargesCrisscross the charges Drop the + and –Drop the + and – Write numbers as subscriptsWrite numbers as subscripts

Binary Ionic CompoundsBinary Ionic Compounds

Example:Example:

magnesium chloridemagnesium chloride

Mg+2 Cl-1 MgCl2

Why does this work?Why does this work?

Mg+2Cl-1

Cl-1

MgCl2 means…

Binary Ionic CompoundsBinary Ionic Compounds

Example:Example:

barium oxidebarium oxide

Ba+2 O-2 BaO

Ba2O2

Practice Practice

Sodium bromideSodium bromide Calcium fluorideCalcium fluoride Magnesium oxideMagnesium oxide Lithium oxideLithium oxide Aluminum oxideAluminum oxide Magnesium fluorideMagnesium fluoride Potassium iodidePotassium iodide Aluminum sulfideAluminum sulfide

NaBr

CaF2

MgO

Li2O

Al2O3

MgF2

KI

Al2S3

Forming Ternary IonicsForming Ternary Ionics

Contain 3 or more elementsContain 3 or more elements Combination of a metal and a polyatomic Combination of a metal and a polyatomic

ion (Table E)ion (Table E)

Writing Ternary IonicsWriting Ternary Ionics

Write each ion (positive first)Write each ion (positive first) Crisscross the chargesCrisscross the charges Drop the + and –Drop the + and – Write numbers as subscriptsWrite numbers as subscripts Keep polyatomic ions in parentheses if Keep polyatomic ions in parentheses if

more than 1more than 1 Never change a polyatomic ion!!!!!Never change a polyatomic ion!!!!!

Ternary Ionic CompoundsTernary Ionic Compounds

Example:Example:

ammonium chlorideammonium chloride

NH4+1 Cl-1 NH4Cl

Ternary Ionic CompoundsTernary Ionic Compounds

Example:Example:

lithium carbonatelithium carbonate

Li+1 CO3-2 Li2CO3

Ternary Ionic CompoundsTernary Ionic Compounds

Example:Example:

calcium hydroxidecalcium hydroxide

Ca+2 OH-1 Ca(OH)2

Why does this work?Why does this work?

Ca+2OH-1

OH-1

Ca(OH)2 means…

PracticePractice

Magnesium hydroxideMagnesium hydroxide Potassium sulfatePotassium sulfate Sodium phosphateSodium phosphate Calcium nitrateCalcium nitrate

Mg(OH)2

K2SO4

Na3PO4

Ca(NO3)2

Stock System for IonicsStock System for Ionics

Some metals can have more than one Some metals can have more than one oxidation state (i.e. transition metals)oxidation state (i.e. transition metals)

Use roman numeralsUse roman numerals

Examples:Examples:

Copper (I) chloride

Copper (II) chloride

Cu+1

Cu+2

Cl-1

CuCl2

CuCl

Cl-1

PracticePractice

Mercury (II) oxideMercury (II) oxide Vanadium (V) bromideVanadium (V) bromide Copper (I) oxideCopper (I) oxide Tin (IV) bromideTin (IV) bromide

HgO

VBr5

Cu2O

SnBr4

Forming Molecular Forming Molecular CompoundsCompounds

Composed of Composed of two non-metalstwo non-metals Electrons are shared so no ions are Electrons are shared so no ions are

formed (covalent bonding).formed (covalent bonding). Called Called moleculesmolecules Prefix system- tells you how many atoms Prefix system- tells you how many atoms

of each elementof each element

PrefixesPrefixes prefixprefix meaningmeaning

Mono-Mono- 11

Di-Di- 22

Tri-Tri- 33

Tetra-Tetra- 44

Penta-Penta- 55

Hexa-Hexa- 66

Hepta-Hepta- 77

Octa-Octa- 88

Nona-Nona- 99

Deca-Deca- 1010

Molecular CompoundsMolecular Compounds

ExamplesExamples

Carbon monoxideCarbon monoxide

Carbon dioxideCarbon dioxide

Phosphorous trichloridePhosphorous trichloride

Phosphorous pentachloridePhosphorous pentachloride

Carbon tetrachlorideCarbon tetrachloride

CO

CO2

PCl3

CCl4

PCl5

PracticePractice

Phosphorous trichloridePhosphorous trichloride Dichlorine monoxideDichlorine monoxide Sulfur tetrafluorideSulfur tetrafluoride Dinitrogen trioxideDinitrogen trioxide Iodine monochlorideIodine monochloride

PCl3

Cl2O

SF4

N2O3

ICl

Naming Ionic CompoundsNaming Ionic CompoundsIonic Compounds (formula units)- Metal and non-metal

Write cation name first (use roman numerals if more than one oxidation state).

Write the first syllable of the anion and add –ide. OR just name the polyatomic ion.

1.

2.

Examples: IonicsExamples: Ionics

LiBrLiBr NaNa22SOSO44

CuClCuCl22

lithium bromide

sodium sulfate

copper (II) chloride

Naming Molecular CmpdsNaming Molecular CmpdsMolecular Compounds (molecules)- two non-metals

Use prefix system on first element (except Mono).

Use prefix system on the second element (including mono) and add –ide ending.

1.

2.

Examples: MolecularExamples: Molecular

NN22OO55

COCO PClPCl33

Dinitrogen pentoxide

Carbon monoxide

Phosporous trichloride

Empirical Formulas vs. Empirical Formulas vs. Molecular FormulasMolecular Formulas

Compounds exist with a definite ratio of Compounds exist with a definite ratio of atoms (ex: water has 2 H per 1 O)atoms (ex: water has 2 H per 1 O)

Empirical formula: lowest whole number Empirical formula: lowest whole number ratioratio

Molecular formula: actual formula (can be Molecular formula: actual formula (can be empirical also). empirical also).

ExamplesExamples

CC22HH88 is a molecular formula (can be is a molecular formula (can be

reduced).reduced). CHCH44 is an empirical formula (can’t be is an empirical formula (can’t be

reduced).reduced).