Chemical Nomenclature

1. Binary Ionic Compounds - Type I2. Binary Ionic Compounds - Type II3. Ionic Compounds & Polyatomic (Complex) Ions4. Hydrated Ionic Compounds5. Binary Covalent Compounds6. Binary Acids7. Oxy-Acids

Definitions An IONIC COMPOUND consists of a metal

cation bonded to a nonmetal anion. Electrostatic attraction holds them together.

A COVALENT COMPOUND consists of two nonmetal atoms sharing valence electrons.

A BINARY compound is one that is made of just two elements. There can be one of each element such as in NaCl or KF. There can also be several of each element such as Na2O or AlBr3.

Type I Binary Ionic Compounds The metal cations in these compounds have

only ONE possible charge. Na+ Zn2+ Al3+ Ca2+

sodium zinc aluminum calcium

The charges are memorized or predicted using a periodic table!

The cations are bonded to nonmetal anions: O2- N3- F- Br -

oxide nitride fluoride bromide

Notice that simple anions are always named with the suffix “ide”

Predicting Charges on Monatomic IonsPredicting Charges on Monatomic IonsKNOW THESE !!!!KNOW THESE !!!!

+1 +2 -3 -2 -1 0

Cd+2

CATIONCATION + + ANIONANION ---> --->

COMPOUNDCOMPOUND

A neutral compound A neutral compound requiresrequires

equal number of + equal number of + and - charges.and - charges.

COMPOUNDS FORMED FROM IONS

NaNa++ + Cl + Cl- - --> NaCl--> NaCl

Naming Compounds

1. Cation first, then anion

2. Monatomic cation = name of the element Ca2+ = calcium ion

3. Monatomic anion = root + -ide Cl = chloride

CaCl2 = calcium chloride

Binary Ionic Compounds:Binary Ionic Compounds:

Naming Binary Ionic Compounds

Examples:NaCl

ZnI2

Al2O3

Learning Check

Complete the names of the following binary compounds:Na3N sodium ________________

KBr potassium ________________

Al2O3 aluminum ________________

MgS _________________________

Formulas for Binary Ionic Compounds

A binary compound is one made of two different elements. There can be one of each element such as in sodium bromide or potassium iodide. There can also be several of each element such as lithium oxide or aluminum bromide.

Writing FormulasFormula Unit – lowest whole number ratio of ions in an ionic compound

Points to remember about writing the formula from the name

1. The order in a formula is first the cation, then the anion. 2. You must know the charges associated with each cation

and anion. 3. The sum of the positive charge and the sum of the

negative charges MUST add up to zero. 4. You MAY NOT adjust the charges of the cations or

anions to get a total charge of zero. 5. You MAY adjust the subscripts to get a total charge of

zero.

Example #1Suppose you must write the formula for sodium chloride.               Write down the Na+ and Cl¯ right next to each other, as in this image:

              Move the positive charge (dropping the sign) to the subscript position of the anion:

              Move the negative charge (dropping the sign) to the subscript position of the cation:

              The result of all this moving is:

              Since subscripts of one are not written, but understood to be present, the final answer is:

Example #2 Write the formula for aluminum oxide. Write down the Al3+ and O2¯ right next to each other :

Move the positive charge (dropping the sign) to the subscript position of the

anion:

Move the negative charge (dropping the sign) to the subscript position of the

cation:

The result of all this moving is:

Learning Check

Write the correct formula for the compounds containing the following ions:1. Sodium sulfide a) NaS b) Na2S c) NaS2

2. Aluminum chloride a) AlCl3 b) AlCl c) Al3Cl3. Magnesium nitride a) MgN b) Mg2N3 c) Mg3N2

Solution

1. Na+ S2-

b) Na2S2. Al3+ Cl-

a) AlCl3

3. Mg2+ N3-

c) Mg3N2

Examples: Type I Binary Ionic Compounds

Write the formulas:

•potassium oxide

• zinc chloride

• silver sulfide

• aluminum nitride

• gallium oxide

•calcium iodide

Write the names:

• K3N

• AgI

• ZnBr2

• Al2O3

• Ba3P2

• LiH

Transition Metals

Elements that can have more than one possible charge MUST have a Roman Numeral to indicate the charge on the individual ion.

1+ or 2+ 2+ or 3+Cu+, Cu2+ Fe2+, Fe3+

copper(I) ion iron(II) ion copper (II) ion iron(III) ion

Names of Variable IonsThese elements REQUIRE Roman Numerals because they can have more than one possible charge:anything except Group 1A, 2A, Ag, Zn, Cd, and Al

(You should already know the charges on these!)

Or another way to say it is: Transition metals and the metals in groups 4A and 5A (except Ag, Zn, Cd, and Al) require a Roman Numeral.

FeCl3 (Fe3+) iron (III) chlorideCuCl (Cu+ ) copper (I) chlorideSnF4 (Sn4+) tin (IV) fluoridePbCl2 (Pb2+) lead (II) chloride

Fe2S3 (Fe3+) iron (III) sulfide

Learning Check

Complete the names of the following binary compounds with variable metal ions:

FeBr2 iron (_____) bromide

CuCl copper (_____) chloride

SnO2 ___(_____ ) ______________

Fe2O3 ________________________

Hg2S ________________________

Examples: Type II Binary Ionic Compounds

Write the formulas:

• iron (II) oxide

• copper (II) chloride

• tin (IV) sulfide

• cupric nitride

• nickel (III) oxide

• ferrous iodide

•cobalt (III) selenide

Write the names:

• Fe2O3

• SnS

• NiBr2

•CuS

• Pb3P2

• CuBr

• FeCl3

Formulas of Ionic Compounds

Formulas of ionic compounds are determined from the charges on the ions

atoms ions

–

Na + F : Na+ : F : NaF

sodium + fluorine sodium fluoride formula

Charge balance: 1+ 1- = 0

NONO33--

nitrate ionnitrate ion

NONO22--

nitrite ionnitrite ion

Polyatomic Ions

Polyatomic (Complex) Ions All of the cations and anions so far have been

simple ions - single atoms that have lost or gained electrons.

Complex polyatomic ions may be cations or anions.

examples:

nitrate: NO3- sulfate: SO4

2- hydroxide: OH-

IONIC COMPOUNDSNH4

+

Cl-

ammonium chloride, NHammonium chloride, NH44ClCl

Things to Notice Most complex ions are anions. Ammonium, NH4

+, is the most common complex cation.

Several complex ions form a short series of ions. The ions differ only in the number of oxygen atoms:

perchorate ClO4- sulfate SO4

2-

chlorate ClO3- sulfite SO3

2-

chlorite ClO2-

hypochlorite ClO- nitrate NO3-

nitrite NO2-

If an ion carries a charge like “-2” or “-3”, a series of related ions can be formed by adding hydrogen cations (H+) while still leaving a net charge:

examples:

Sulfide: S2- hydrogen sulfide: HS-

(bisulfide)

Sulfate: SO42- hydrogen sulfate: HSO4

-

(bisulfate)

Carbonate: CO32- hydrogen carbonate: HCO3

-

(bicarbonate)

Phosphate: PO43- hydrogen phosphate: HPO4

2-

dihydrogen phosphate: H2PO4-

Ionic Compounds containing Polyatomic Ions

Writing Formulas Write each ion, cation first. Don’t show

charges in the final formula. Overall charge must equal zero.

If charges cancel, just write symbols. If not, use subscripts to balance charges.

Use parentheses to show more than one of a particular polyatomic ion.

Use Roman numerals to indicate the ion’s charge when needed (stock system)

Learning Check

1. aluminum nitrate a) AlNO3 b) Al(NO)3 c) Al(NO3)3

2. copper(II) nitrate a) CuNO3b) Cu(NO3)2 c) Cu2(NO3)

3. Iron (III) hydroxide a) FeOH b) Fe3OH c) Fe(OH)3

4. Tin(IV) hydroxide a) Sn(OH)4 b) Sn(OH)2 c) Sn4(OH)

Writing formulas with Complex Ionsa) Ammonium chloride

b) Silver sulfate

c) Aluminum hydroxide

d) Calcium phosphate

e) Iron (III) nitrite

f) Copper(II) permanganate

g) Ammonium dichromate

h) Zinc acetate

More Formulas with Complex Ionsa) NaHCO3

b) Ni(HS)2

c) Al(ClO4)3

d) Ba(H2PO4)2

e) Fe2(SO2)3

f) CuHSO4

g) Zn(IO4)2

Mixed Practice!Name the following:1. Na2O

2. CaCO3

3. PbS2

4. Sn3N2

5. Cu3PO4

6. HgF2

Mixed Up… The Other WayWrite the formula:1. Copper (II) chlorate2. Calcium nitride3. Aluminum carbonate4. Potassium bromide5. Barium fluoride6. Cesium hydroxide

Naming Molecular Compounds

CH4 methaneBCl3 boron trichloride

CO2 Carbon dioxide

All are formed from two or more nonmetals.

Ionic compounds generally involve a metal and nonmetal (NaCl)

Binary Covalent Compounds Covalent compounds are made of two NONMETAL

elements sharing valence electrons. There are no ions involved!! Because there are no charges to help us write the

formulas of covalent compounds, prefixes are used to indicate the number of each atom present in the formula.

The first element receives a prefix if the subscript is greater than one. The second element ALWAYS gets a prefix.Change the ending of the second element to -ide. The prefix, “mono”

is never used for the first element in the formula!

Molecular (Covalent) Nomenclaturefor two nonmetals

Prefix System (binary compounds)CO2 is named “carbon dioxide”CO is named “carbon monoxide”N2O is named “dinitrogen monoxide”SO3 is named “sulfur trioxide”

.

PREFIXmono-di-tri-tetra-penta-hexa-hepta-octa-nona-deca-

NUMBER12345678910

Molecular Nomenclature Prefixes

CCl4

N2O

SF6

Molecular Nomenclature: Examples

arsenic trichloride

dinitrogen pentoxide

tetraphosphorus decoxide

More Molecular Examples

Learning Check

Fill in the blanks to complete the following names of covalent compounds.

CO carbon ______oxideCO2 carbon _______________

PCl3 phosphorus _______chloride

CCl4 carbon ________chloride

N2O _____nitrogen _____oxide

Learning Check 1.P2O5 a) phosphorus oxide

b) phosphorus pentoxidec) diphosphorus pentoxide

2.Cl2O7 a) dichlorine heptoxideb) dichlorine oxidec) chlorine heptoxide

3. Cl2 a) chlorineb) dichlorinec) dichloride

Binary Acids A simple definition of an “acid” is a substance which

produces H+ ions in water.

Most acids have hydrogen ions in their formulas.

A binary acid composed of a hydrogen cation bonded to one other element:

HCl HBr H2Shydrochloric acid hydrobromic acid hydrosulfuric acid

Binary acids are always named: hydro____ic acid

Oxy-Acids An acid can also be made of a hydrogen ion bonded to a complex

ion.

Complex ions whose names end in “ate”:

NO3- SO4

2- CO32- PO4

3-

nitric acid: HNO3

sulfuric acid: H2SO4

carbonic acid: H2CO3

phosphoric acid: H3PO4

Can you propose a rule for naming oxy-acids

with complex ions ending in “ate”?

More Oxy-Acids Complex ions ending in “ite”:

NO2- SO3

2- ClO- ClO2-

nitrous acid: HNO2

sulfurous acid:H2SO3

hypochlorous acid: HClO

chlorous acid HClO2

Can you propose a rule for naming oxy-acids

with complex ions ending in “ite”?

Hydrated Ionic Compounds A HYDRATE is an salt that has water molecules

trapped within its crystals. Every hydrate has a certain number of water

molecules associated with each formula unit of the ionic compound. The number of water molecules is indicated by using prefixes.

mono hexadi heptatri octatetra nonapenta deca

CuSO4 · 5 H2O

copper (II) sulfate pentahydrate

MgCO3 ·10 H2O

magnesium carbonate decahydrate

Examples of hydrates: Write the formulas:

copper(II) fluoride tetrahydrate CuF2 ·4 H2O

calcium nitrate trihydrate Ca(NO3)2 ·3 H2O

Write the names:

MgSO4 · 7 H2O magnesium sulfate heptahydrate

FeCl2 · H2O iron (II) chloride monohydrate