chapters 8 & 9

Chapters 8 & 9Naming Compounds

Writing Formulas

Compounds Follow the Law of Definite Proportion. Have a constant composition. Have to add the same number of atoms

every time. Two types.

Two Types of Compounds1 Ionic Compounds Made of cations and anions. Metals and nonmetals. The electrons lost by the cation are

gained by the anion. The cation and anions surround each

other. Smallest piece is a FORMULA UNIT.

Crystalline Structure – Ionic Compound

Two Types of Compounds2 Molecular Compounds

Made of molecules. Made by joining nonmetal atoms

together into molecules. H2O, CO2, C6H12O6

Chemical Formulas Shows the kind and number of

atoms in the smallest piece of a substance.

Molecular formula- number and kinds of atoms in a molecule.

CO2

C6H12O6

Two Types of Compounds

Smallest Piece

Melting Point

State

Types of Elements

Formula Unit Molecule

Metal and Nonmetal

Nonmetals

SolidSolid, Liquid or Gas

High >300ºC Low <300ºC

Ionic Molecular

Chemical Formulas More than one atom? –use a

subscript (H2O) There are 7 diatomic elements Hydrogen (H2), Nitrogen (N2),

Oxygen (O2), Fluorine (F2), Chlorine (Cl2), Bromine (Br2), and Iodine (I2)

Remember: “Br I N Cl H O F”

+2

+1

+3 -3 -2 -1

Systematic Naming There are too many compounds to

remember the names of them all. Compound is made of two or more

elements. Put together atoms. Name should tell us how many and

what type of atoms.

Naming Ions We will use the systematic way. Cation- if the charge (oxidation #) is

always the same, use name of the metal.

Transition metals can have more than one charge or oxidation number.

Therefore, indicate the charge with roman numerals in parenthesis.

Fe+3 is named - iron (III) ion Movie

Exceptions: Some of the transition metals have

only one ionic charge:

–Do not use roman numerals for these:

–Silver is always 1+ (Ag1+)

–Cadmium and Zinc are always 2+ (Cd2+ and Zn2+)

Metals with Multiple ChargesTransition MetalsTransition Metals

Here it is easier to list the ones that only have a single common oxidation state.

All Group 3B - 3+

Ni, Zn, Cd - 2+

Ag - 1+

Lanthanides and actinides - 3+

Name These Ions

Na+1 Ca+2 Al+3 Fe+3 Fe+2 Pb+2 Li+1

sodium ion

calcium ion

aluminum ion

iron (III) ion

iron (II) ion

lead (II) ion

lithium ion

Write Formulas for These Potassium ion Magnesium ion Copper (II) ion Chromium (VI) ion Barium ion Mercury (II) ion

K+1

Mg+2

Cu+2

Cr+6

Ba+2

Hg+2

Naming Anions Anions are always the same. Change the element ending to – ide F-1 Fluorine

Naming Anions Anions are always the same. Change the element ending to – ide F-1 Fluorin

Naming Anions Anions are always the same Change the element ending to – ide F-1 Fluori

Naming Anions Anions are always the same Change the element ending to – ide F-1 Fluor

Naming Anions Anions are always the same Change the element ending to – ide F-1 Fluori

Naming Anions Anions are always the same Change the element ending to – ide F-1 Fluorid

Naming Anions Anions are always the same Change the element ending to – ide F-1 Fluoride

Name These Ions

Cl-1 N-3 Br-1 O-2

Ga+3

Chloride

Nitride

Bromide

Oxide

Gallium (III)

Write These

sulfide ion iodide ion phosphide ion strontium ion

S-2

I-1

P-3

Sr+2

Polyatomic Ions Groups of atoms that stay together and

have a charge. Use your reference sheet Acetate C2H3O2

-1

Nitrate NO3-1

Nitrite NO2-1

Hydroxide OH-1

Permanganate MnO4-1

Cyanide CN-1

Polyatomic Groups with a Charge

Polyatomic Ions Sulfate SO4

-2

Sulfite SO3-2

Carbonate CO3-2

Chromate CrO4-2

Dichromate Cr2O7-2

Phosphate PO4-3

Phosphite PO3-3

Ammonium NH4+1

Common Polyatomic Ions

Ionic Compounds

We’ve named the ions, so now it is time to name the

compounds!

Naming Binary Ionic Compounds Binary Compounds - 2 elements. Ionic - a cation and an anion. To write the names just name the two

ions. Easy with Representative elements. NaCl = Na+ Cl- = sodium chloride

MgBr2 = Mg+2 Br- = magnesium bromide

Naming Binary Ionic Compounds The problem comes with the transition

metals. Need to figure out their charges. The compound must be neutral. Same number of + and – charges. Use the anion to determine the charge

on the positive ion.

Balancing Charges

3P2ZnHow many zinc +2 charges are needed to balance phosphide’s -3 charge?

What subscripts must be placed on the line?

The numbers used must always be whole numbers.

23PZn

Naming Ionic CompoundsMany metals form more than one compound with

some anions.

For these, roman numerals are used in the name to indicate the charge on the metal.

Cu1+ + O2- = Cu2O

copper(I) oxide copper(I) oxide

Cu2+ + O2- = CuO

copper(II) oxide copper(II) oxide

More ExamplesFeCl2 iron(II) chloride

FeCl3 iron(III) chloride

SnS tin(II) sulfide

SnS2 tin(IV) sulfide

AgCl silver chlorideCdS cadmium sulfideNoteNote

Some transition metals only have a single state so the roman numeral may be omitted.

Some main group metals, with high atomic numberhave more than one state, roman numbers are used.

Naming Binary Ionic Compounds Write the name of CuO Need the charge of Cu O is -2 Copper must be +2 Copper (II) oxide Name CoCl3

Cl is -1 and there are three of them = -3 Co must be +3 Cobalt (III) chloride

Naming Binary Ionic Compounds Write the name of Cu2S. Since S is -2, the Cu2 must be +2, so

each one is +1. copper (I) sulfide Fe2O3 Each O is -2 3 x -2 = -6 2 Fe must = +6, so each is +3. iron (III) oxide

Naming Binary Ionic Compounds Write the names of the following KCl Na3N

CrN

Sc3P2

PbO

PbO2

Na2Se

Potassium Chloride

Sodium Nitride

Chromium (III) Nitride

Scandium (II) Phosphide

Lead (II) Oxide

Lead (IV) Oxide

Sodium Selenide

Ternary Ionic Compounds Will have polyatomic ions At least three elements Name the ions

NaNO3

CaSO4

CuSO3

(NH4)2O

Sodium Nitrate

Calcium Sulfate

Copper (II) Sulfite

Ammonium Oxide

Ternary Ionic Compounds

LiCN Fe(OH)3

(NH4)2CO3

NiPO4

Lithium Cyanide

Iron (III) Hydroxide

Ammonium Carbonate

Nickel (III) Phosphate

Writing Formulas The charges have to add up to zero. Get charges on pieces. Cations from name of table. Anions from table or polyatomic. Balance the charges by adding

subscripts. Put polyatomics in parenthesis.

Writing Formulas Write the formula for calcium chloride. Calcium is Ca+2 Chloride is Cl-1 Ca+2 Cl-1 would have a +1 charge. Need another Cl-1 Ca+2 Cl2

-1

Write the Formulas for These lithium sulfide tin (II) oxide tin (IV) oxide magnesium fluoride copper (II) sulfate iron (III) phosphide gallium (I) nitrate iron (III) sulfide

Li2S

SnO

SnO2

MgF2

CuSO4

FeP

GaNO3

Fe2S3

Write the Formulas for These ammonium chloride ammonium sulfide barium nitrate

NH4Cl

(NH4)2S

Ba(NO3)2

Things To Look For If cations have (roman #), the number is

their charge. If anions end in -ide they are probably

off the periodic table (Monoatomic) If anion ends in -ate or -ite it is

polyatomic

Molecular Compounds

Writing Names and Formulas

Molecular Compounds made of just nonmetals smallest piece is a molecule can’t be held together because of

opposite charges can’t use charges to figure out how

many of each atom

Easier Ionic compounds use charges to

determine how many of each.

– Have to figure out charges.

– Have to figure out numbers. Molecular compounds name tells you

the number of atoms. Uses prefixes to tell you the number

Prefixes 1 mono- 2 di- 3 tri- 4 tetra- 5 penta- 6 hexa- 7 hepta- 8 octa-

Prefixes 9 nona- 10 deca- To write the name write two words

Prefixes 9 nona- 10 deca-

To write the name, write two words with

Prefix name Prefix name -ide

Prefixes 9 nona- 10 deca- To write the name write two words

One exception is we don’t write mono- if there is only one of the first element.

Prefix name Prefix name -ide

Prefixes 9 nona- 10 deca- To write the name write two words One exception is we don’t write mono- if

there is only one of the first element. No double vowels when writing names

(oa oo)

Prefix name Prefix name -ide

Name These

N2O

NO2

Cl2O7

CBr4

CO2

BaCl2

Dinitrogen Monoxide

Nitrogen Dioxide

Dichlorine Heptoxide

Carbon Tetrabromide

Carbon Dioxide

Barium Chloride

Write Formulas for These diphosphorus pentoxide tetraiodine nonoxide sulfur hexafluoride nitrogen trioxide carbon tetrahydride phosphorus trifluoride aluminum chloride

P2O5

I4O9

SF6

NO3

CH4

PF3

AlCl3

Nomenclature FlowchartIs a metal presentas the first element?

Can the metal havemore than oneoxidation state?

Use prefixes(mono, di, tri ...)

Roman numeralsare not needed.

Use Roman numerals

NoNo

NoNo

YesYes

YesYes

Helpful to remember...1. In an ionic compound, the net ionic

charge is zero (criss-cross method)

2. An -ide ending generally indicates a binary compound

3. An -ite or -ate ending means there is a polyatomic ion that has oxygen

4. Prefixes generally mean molecular; they show the number of each atom

Helpful to remember...5. A Roman numeral after the name of

a cation shows the ionic charge of the cation.

Acids

Writing Names and Formulas

Acids Compounds that give off hydrogen ions

when dissolved in water. Must have H in them. Will always be an H next to an anion. The anion determines the name.

Typical Acids and Bases

Acid

HCl HNO3 H2SO4 H3PO4

Base

NaOH KOH Ba(OH)2

Al(OH)3

Naming Acids If the anion attached to hydrogen ends

in -ide, use the prefix hydro- and change -ide to -ic acid

HCl - hydrogen ion and chloride ion hydrochloric acid H2S hydrogen ion and sulfide ion hydrosulfuric acid

Naming Acids If the anion has oxygen in it, no hydro It ends in -ate or -ite Change the suffix -ate to -ic acid HNO3 Hydrogen and nitrate ions

Nitric acid Change the suffix -ite to -ous acid HNO2 Hydrogen and nitrite ions

Nitrous acid

Oxyanion and Oxyacids An ion with oxygen in it is called an

oxyanion. An acid with an oxyanion in it is called

an oxyacid.

Name These

HF H3P

H2SO4

H2SO3

HCN H2CrO4

H3PO4

Hydrofluoric acid

Hydrophosphoric acid

Sulfuric acid

Sulfurous acid

Hydrocyanic acid

Chromic acid

Phosphoric acid

Writing Formulas Hydrogen will always be first Name will tell you the anion Make the charges cancel out Starts with hydro- no oxygen, -ide No hydro, -ic comes from -ate, -ous

comes from -ite

Write Formulas for These hydroiodic acid acetic acid carbonic acid phosphoric acid hydrobromic acid

HI

HC2H3O2

H2CO3

H3PO4

HBr

More Acid Practice

Name and Formula

Name the Formula H2S

H2CrO4

HClO3

H2CO3

HSCN H2SO3

H3PO4

Hydrosulfuric acid

Chromic acid

Chloric acid

Carbonic acid

Thiocyanic acid

Sulfurous acid

Phosphoric acid

Write the Formula Hydroiodic acid Hydrobromic acid Perchloric acid Sulfuric acid Hydrophosphoric acid Hydroselenic acid Chlorous acid

HI

HBr

HClO4

H2SO4

H3P

H2Se

HClO2