compounds are two or more elements that are held together by opposite charge attraction. oxygen-8...

Compounds are two or more elements that are held together by opposite charge attraction.

Oxygen-8Magnesium-12 8 (+)10 (-)-2 Charge

12 (+)10 (-)+2 Charge

Metal Non-metal

Metals combine with non-metals

Metals loose electrons to non-metals

They then attract because their charges will be opposite.

-3 -2 -1

Most of the negative ions have a set negative charge

Metals in groups 1A, 2A, and 3A have set positive charges when they lose electrons. So does Zn, Cd, & Ag. They are attracted to either a single non-metal ion or a polyatomic ion…+1

+2 +3

+1 +2

POLYATOMIC IONS (charged building blocks)Polyatomic ions are mostly made of two non-metals.

Ions with -1 chargeperbromate BrO4

-1

bromate BrO3-1

bromite BrO2-1

hypobromite BrO-1

perchlorate ClO4-1

chlorate ClO3-1

chlorite ClO2-1

hypochlorite ClO-1

periodate IO4-1

iodate IO3-1

iodite IO2-1

hypoiodite IO-1

nitrate NO3-1

nitrite NO2-1

hydroxide OH-1

cyanide CN-1

acetateC2H3O2

-1

Permanganate MnO4-1

bicarbonate HCO3-1

Ions with a -2 Chargecarbonate CO3

-2

sulfate SO4-2

sulfite SO3-2

chromate CrO4-2

dichromate Cr2O7-2

oxalate C2O4-2

Ions with a -3 Charge

phosphate PO4-3

phosphite PO3-3

arsenate AsO4-3

Ions with +1 chargeammonium ion

NH4+1

Ions with -1 chargeperbromate BrO4

-1

bromate BrO3-1

bromite BrO2-1

hypobromite BrO-1

perchlorate ClO4-1

chlorate ClO3-1

chlorite ClO2-1

hypochlorite ClO-1

periodate IO4-1

iodate IO3-1

iodite IO2-1

hypoiodite IO-1

-1

These polyatomic ions match the charge of their group

-2

These polyatomic ions match the charge of their group

Ions with a -2 Chargesulfate SO4

-2

sulfite SO3-2

Ions with a -3 Chargephosphate PO4

-3

phosphite PO3-3

-3

It is also important to memorize the oxidation of the ions that have fixed oxidation numbers (positive or negative). In particular, those from groups 1A, 2A, 3A, 4A, 5A, 6A, 7A, 8A and the elements: Zn, Cd and Ag. Use the following periodic chart to determine their oxidation numbers. Just click on the element symbol…

N

Elements with Fixed Oxidation Numbers

La Hf Ta Re OsCe Ba Tl Pb Bi Po At RnIr Pt Au Hg

Y Zr Nb Mo Tc RuRb Sr In Sn Sb Te I XeRh Pd Ag Cd

Sc Ti V Cr Mn FeK Ca Ga Ge As Se Br KrCo Ni Cu Zn

Al Si P S Cl ArNa Mg

B C O F NeLi Be

H H He

Ac Rf Db Sg Rh HsFr Ra Mt

+1+2 +31A

2A

8A

0-4-3-2-17A

6A5A4A3A

W

Nd Pm Sm Eu Gd TbCe Pr Yb LuDy Ho Er Tm

Np Am Cm BkTh Pa No LrCf Es Fm MdU Pu

Click on element to see its oxidation number(s)

Next Slide

Naming Ionic CompoundsThe positive ion (usually a metal) is named first while the negative ion (a non-metal or a polyatomic ion) is named last.

The charge on the negative ion is used to determine the charge on the positive ion. In-order for the total oxidation state to be zero, the total positive charge must equal the total negative charge. A simple algebraic equation can be used to determine the charge on a single metal ion. This charge is expressed as a “Roman Numeral” in parenthesis that immediately follows the name of the metal.

CuSO4

Cu?SO4-2

x +(-2)=0

X = 2

Copper (II) Sulfate

Naming Ionic CompoundsThe positive ion (usually a metal) is named first while the negative ion (a non-metal or a polyatomic ion) is named last.

The charge on the negative ion is used to determine the charge on the positive ion. In-order for the total oxidation state to be zero, the total positive charge must equal the total negative charge. A simple algebraic equation can be used to determine the charge on a single metal ion. This charge is expressed as a “Roman Numeral” in parenthesis that immediately follows the name of the metal.

Cu2SO4

Cu2+xSO4

-2

2x +(-2)=0

x = 1

Copper (I) Sulfate

Naming Ionic Compounds• If the positive ion is one that has a fixed oxidation

number then no Roman Numeral is used. • Everyone should know the charge of fixed ions.

These include metals in group 1A, 2A and the specific metals: Al, Zn, Cd & Ag (zinc, cadmium and silver).

CaSO4

Calcium Sulfate

No Roman Numeral

Examples #1- Formulas to Names

CuSO3

copper

I’m a polyatomi

c ion

1. Write the names of the ions

Final Name

sulfite(II)

x

X + (- 2) = 0

X = +2

Cu SO3

= 0

You must know the charge on the sulfite ion is -2

The sum of the positive and negative charges must equal zero

2. Determine the charge of the positive ion

-

2

+2 +2

Next

+2

Examples #2- Formulas to Names

KMnO4

potassium

I’m a polyatomi

c ion

1. Write the names of the ions

Final Name

permanganate

If the positive ion has a fixed charge, you are finished.

Examples #3- Formulas to Names

NH4NO3

ammonium

I’m a polyatomi

c ion

2. Determine the charge of the positive ion

1. Write the names of the ions

Final Name

nitrate

If the positive ion has a fixed charge, you are finished.

Examples #4- Formulas to Names

SnF2

tin

I’m not a polyatomi

c ion

2. Determine the charge of the positive ion

1. Write the names of the ions

Final Name

fluoride(II)

Snx (F-1)2 = 0

X + 2(-1) = 0

X = +2

Examples #5- Formulas to Names

Ba(ClO4)2

barium

I’m a polyatomi

c ion

2. Determine the charge of the positive ion

1. Write the names of the ions

Final Name

perchlorateIf the positive ion has a fixed charge, you are finished.

Examples #6- Formulas to Names

Cu2S

copper

I’m not a polyatomi

c ion

2. Determine the charge of the positive ion

1. Write the names of the ions

Final Name

sulfide(I)

2Cux (S)-2 = 0

2X + (-2) = 0

X = +1

Examples #6- Formulas to Names

Cu2S

copper

1.Write the names of the ions

Final Name

sulfide(I)

x

2X + (- 2) = 0

2X = +2

(Cu )2 S

You must know the charge on the sulfide ion is -2

The sum of the positive and negative charges must equal zero

2. Determine the charge of the positive ion

-2

+2 +2

Next

+1

2 2

X = +1

Examples #7- Formulas to Names

Na2Cr2O7

sodium

I’m a polyatomi

c ion

2. Determine the charge of the positive ion

1. Write the names of the ions

Final Name

dichromate(I)

2(Nax)(Cr2O7)-2 = 0

2X + (-2) = 0

X = +1

If the positive ion has a fixed charge, it is not shown

FePO3 .3H2O

Examples #9- Formulas to Names

iron

I’m a polyatomi

c ion

2. Determine the charge of the positive ion

1. Write the names of the ions

Final Name phosphite(III)

Fex (PO3 -3) = 0

X + (-3) = 0

X = +3

hydrate

I’m a hydrated compound, this

part will be named last

.3H2O3

tri

Examples #10- Formulas to Names

LiCN

lithium

I’m a polyatomi

c ion

2. Determine the charge of the positive ion

1. Write the names of the ions

Final Name

cyanideIf the positive ion has a fixed charge, you are finished.

Writing Ionic Formulas• It is easier to write the formula of an

ionic compound from its name than the reverse.

• The oxidation number of the negative ion must be memorized in all cases. Refer to the table of polyatomic ions.

aluminum chloride

Example #1-Names to Formulas

AlCl3

2. Determine number of ions

1. Write symbols of elements

Final Formula

Al Cl-1

1

If there is only one atom the “1” is not shown

+3

If there is no Roman Numeral, you need to know the fixed oxidation number of the positive ion.

Next

Example #2-Names to Formulas

cobalt(II) bromate

Co BrO3

2. Determine number of ions

1. Write symbols of elements

Final Formula

(Co+2)(BrO3-1)= 0

(BrO3)

2Next

Example #3-Names to Formulas

nickel(III) acetate

Ni C2H3O2

2. Determine number of ions

1. Write symbols of elements

Final Formula

(Ni+3)x(C2H3O2-1)y

= 0

(C2H3O2)3

Next

Example #4-Names to Formulas

lithium phosphate

Li PO4

2. Determine number of ions

1. Write symbols of elements

Final Formula

(Li )x(PO4-3)y

= 0

3

+1

(PO4)If there is no Roman Numeral, you need to know the fixed oxidation number of the positive ion.

Next

Practice Problems

By now you should have an idea of what is expected when naming covalent binary compounds using prefixes.

In order to master this naming system you need to practice until you feel proficient in naming compounds using prefixes.

Practice Problem #1Fe(NO3)3

Choose the correct name for the compound

1. Iron trinitrate

2. iron(I) nitrate

3. iron(III) nitrite

4. iron(III) nitrate

5. none of the abovenext

problemPolyatomic

IonsPeriodic Chart

Practice Problem #2sodium chlorite

Choose the correct formula for the compound

1. NaCl

2. NaClO

3. NaClO2

4. Na(ClO)2

5. none of the above

EndPeriodic Chart

POLYATOMIC IONS

Ions with -1 chargeperbromate BrO4

-1

bromate BrO3-1

bromite BrO2-1

hypobromite BrO-1

perchlorate ClO4-1

chlorate ClO3-1

chlorite ClO2-1

hypochlorite ClO-1

periodate IO4-1

iodate IO3-1

iodite IO2-1

hypoiodite IO-1

nitrate NO3-1

nitrite NO2-1

hydroxide OH-1

cyanide CN-1

thiocyanate SCN-1

acetate C2H3O2-1

Permanganate MnO4

-1

bicarbonate HCO3-1

Ions with a -2 Chargecarbonate CO3

-2

phthalate C8H4O4-2

sulfate SO4-2

sulfite SO3-2

chromate CrO4-2

dichromate Cr2O7-2

oxalate C2O4-2

peroxide O2-2

Ions with a -3 Chargephosphate PO4

-3

phosphite PO3-3

arsenate AsO4-3

Ions with +1 chargeammonium ion

NH4+1

return

N

Oxidation Numbers (most common)

La Hf Ta Re OsCe Ba Tl Pb Bi Po At RnIr Pt Au Hg

Y Zr Nb Mo Tc RuRb Sr In Sn Sb Te I XeRh Pd Ag Cd

Sc Ti V Cr Mn FeK Ca Ga Ge As Se Br KrCo Ni Cu Zn

Al Si P S Cl ArNa Mg

B C O F NeLi Be

H H He

Ac Rf Db Sg Rh HsFr Ra Mt

+1+2+31A

2A

8A

0-4-3-2-17A

6A5A4A3A

W

Nd Pm Sm Eu Gd TbCe Pr Yb LuDy Ho Er Tm

Np Am Cm BkTh Pa No LrCf Es Fm MdU Pu

Click on element to see its oxidation number(s)

+1 +2 +2 +3 +2 +4

return