Chapter 7:

Language of Chemistry

IUPAC

• The International Union of Pure and Applied Chemistry, IUPAC, has set rules for naming compounds.

• IUPAC set the rules for the naming and classification of inorganic compounds in 1940.

• These rules, referred to as IUPAC nomenclature, are still in use today.

Classification of Compounds

Ionic Compounds

• Binary ionic compounds contain two

elements: one metal and one

nonmetal.

• NaCl and AlCl3 are binary ionic compounds.

• Ternary ionic compounds contain

three elements, at least one metal and

one nonmetal.

• KNO3 and Al(NO3)3 are ternary ionic compounds.

Molecular Compounds

• Binary molecular compounds

contain two elements and both are

nonmetals.

• Some examples of binary molecular

compounds are ammonia, NH3; methane, CH4;

carbon dioxide, CO2; and tetraphosphorous

trisulfide, P4S3.

Aqueous Acids

• An aqueous solution is produced when a compound dissolves in water. It is indicated by the symbol (aq).

• A binary acid is an aqueous solution of a compound containing hydrogen

and one other nonmetal. HF (aq) is a binary acid.

• A ternary oxyacid is an aqueous

solution of a compound containing

hydrogen, oxygen, and one other nonmetal. HNO3(aq) is a ternary oxyacid.

Classification of Ions

• An ion is an atom or group of atoms with a charge.

• A positively charged ion is called a cation.

• A negatively charged ion is called an anion.

• A group of atoms bound together that has an overall

charge is called a polyatomic anion.

Metals Form Positive Ions

Metals form positive ions (cations)

• by a loss of their valence electrons.

• with the electron configuration of the

nearest noble gas.

• that have fewer electrons than protons.

Group 1A metals ion 1+

Group 2A metals ion 2+

Group 3A metals ion 3+

Monoatomic Cations

• Cations are named for the parent atom followed by the

word “ion.”

• Na+ is named “sodium ion.”

• Al3+ is named “aluminum ion.”

• This rule applies for metals that usually form one ion.

This includes the main group metals along with Ag+,

Zn2+, and Cd2+. Exceptions include tin and lead.

Metals that Form

Multiple Ions

If a metal can form more than

one cation, it is named by the

parent followed by the charge in

Roman numerals in parentheses,

ending with the word “ion.”

Metals that Form Multiple Ions

Cation Stock System

Cr2+ chromium (II)

Cr3+ chromium (III)

Mn2+ manganese (II)

Fe2+ iron (II)

Fe3+ iron (III)

Co2+ cobalt (II)

Co3+ cobalt (III)

Ni2+ nickel (II)

Cu1+ copper (I)

Cu2+ copper (II)

Sn2+ tin (II)

Sn4+ tin (IV)

Hg22+ mercury (I)

Hg2+ mercury (II)

Pb2+ lead (II)

Pb4+ lead (IV)

Non-metals form Negative Ions

Nonmetals form negative ions (anions)

• by gaining electrons.

• form negatively charged ions with 3-, 2-, or 1- charges.

• Non-metals ions are named by changing the end of their

element name with the suffix –ide.

• N3− is the nitride ion.

• O2− is the oxide ion.

• Br− is the bromide ion.

Ion Charges

Some Ionic Charges

I-

Learning Check

A. The symbol for the magnesium ion is

1) Mg1+. 2) Mg2+. 3) Mg2- .

B. For aluminum to achieve a noble gas configuration, the change of electrons requires a

1) loss of 3e-. 2) gain of 3e-. 3) a gain of 5e-.

C. The symbol for the aluminum ion is

1) Al3+. 2) Al3-. 3) Al+.

D. The number of valence electrons in sulfur is

1) 4e-. 2) 6e-. 3) 8e-.

E. The ionic charge of sulfur is

1) 2+. 2) 2-. 3) 4-.

Ionic Compounds

Ionic compounds

• consist of positive

and negative ions.

• have attractions called ionic bonds between

positively and negatively charged ions.

• have high melting and boiling points.

• are solid at room temperature.

NaCl formation

reaction video

An ionic formula

• consists of positively and negatively charged ions. • is neutral.

M+ + X- MX

Cation + Anion Ionic compound

• the symbol of the metal (cation) is written first followed

by the symbol of the nonmetal (anion).

Ionic Formulas

Ionic Formulas

Examples:

1). Na+ and Cl– form NaCl or sodium chloride.

2). Mg2+ and Cl– form MgCl2 or magnesium chloride.

3). Na+ and S2– form Na2S or sodium sulfide.

Select the correct formula for each of the following ionic compounds.

A. Al3+ and Cl-

1) AlCl3 2) AlCl 3) Al3Cl

B. Mg2+ and N3-

1) MgN 2) Mg2N3 3) Mg3N2

C. K+ and I-

1). K2I 2). KI2 3). KI

Learning Check

Naming Binary Ionic Compounds

Naming FeCl2

To name FeCl2

1. Determine the charge of the cation using the charge of the anion (Cl-).

2. Name the cation by the element name and add a

Roman numeral in parenthesis to show its charge.

Fe2+ = iron(II)

3. Write the anion with an ide ending.

FeCl2 = iron(II) chloride

Naming Cr2O3

To name Cr2O3

1. Determine the charge of cation from the anion (O2-).

2. Name the cation by the element name and add a

Roman numeral in parenthesis to show its charge.

Cr3+ = chromium(III)

3. Write the anion with an ide ending.

chromium(III) oxide = Cr2O3

Learning Check

Select the correct name for each.

A. Fe2S3

1) iron sulfide

2) iron(II) sulfide

3) iron(III) sulfide

B. CuO

1) copper oxide

2) copper(I) oxide

3) copper(II) oxide

Learning Check

What is the correct formula for each of the following?

A. Copper(I) nitride

1) CuN 2) CuN3 3) Cu3N

B. Lead(IV) oxide

1) PbO2 2) PbO 3) Pb2O4

Name the following ionic compounds.

A. MgI2

B. CaO

C. FeBr2

D. K3P

E. CuCl

Learning Check

A polyatomic ion

• is a group of atoms.

• has an overall ionic charge.

Some examples of polyatomic ions are

NH4+ ammonium OH− hydroxide

NO3−

nitrate NO2

− nitrite

CO32− carbonate PO4

3− phosphate

HCO3− hydrogen carbonate

(bicarbonate)

Polyatomic Ions

Polyatomic anions that contain one or more elements combined

with oxygen are called oxyanions.

• end in ate.

NO3− nitrate PO4

3− phosphate

• with one oxygen less end in ite.

NO2− nitrite PO3

3− phosphite

• with hydrogen attached use the prefix hydrogen (or bi).

HCO3− hydrogen carbonate (bicarbonate)

HSO3− hydrogen sulfite (bisulfite)

Polyatomic Ions

The positive ion is named first followed by the name of the

polyatomic ion.

NaNO3 sodium nitrate

K2SO4 potassium sulfate

Fe2(CO3) 3 iron(III) carbonate

NH4Cl ammonium chloride

Naming Ternary Ionic Compounds

Match each formula with the correct name.

A. MgS 1) magnesium sulfite

MgSO3 2) magnesium sulfate

MgSO4 3) magnesium sulfide

B. Ca(ClO3)2 1) calcium chlorate

CaCl2 2) calcium chlorite

Ca(ClO2)2 3) calcium chloride

Learning Check

Learning Check

Name each of the following compounds:

A. Mg(NO3)2

B. Cu(ClO3)2

C. PbO2

D. Fe2(SO4)3

E. Ba3(PO3)2

Select the correct formula for each.

A. aluminum nitrate

1) AlNO3 2) Al(NO)3 3) Al(NO3)3

B. copper(II) nitrate

1) CuNO3 2) Cu(NO3)2 3) Cu2(NO3)

C. iron(III) hydroxide

1) FeOH 2) Fe3OH 3) Fe(OH)3

D. tin(IV) hydroxide

1) Sn(OH)4 2) Sn(OH)2 3) Sn4(OH)

Learning Check

Learning Check

Write the chemical formula for each of the following compounds:

A. calcium carbonate

B. chromium (III) bromide

C. mercury (I) oxide

D. ammonium chlorite

E. silver nitrate

Critical Thinking: Potassium

• Potassium is an extremely reactive element (its violent reaction

with water is pictured below).

• How can such a reactive element (with water) be essential for

human life?

• Good sources of potassium include fish, meat, fruit, dark

vegetables, and nuts.

Binary Molecular Compounds

• Binary molecular compounds are composed of two

nonmetal elements.

• A molecule is the simplest representative particle of a

binary molecular compound.

• IUPAC has set the following order for writing the

elements in a binary molecular compound:

• C, P, N, H, S, I, Br, Cl, O, and F

Naming Molecular Compounds To name molecular compounds

• STEP 1: First element in formula is named first.

• STEP 2: Second element is named next using the prefixes in table 4.12 to denote the number of atoms present and an ide ending.

• STEP 3: Prefixes on 1st element are used EXCEPT mono.

ex. CO is carbon monoxide

Table 4.12

Examples

1. BF3 = boron trifluoride

2. NO = nitrogen monoxide

3. N2O5 = dinitrogen pentoxide

4. P4S3 = tetraphosphorus trisulfide

Common names always used:

H2O = water

NH3 = ammonia

Select the correct name for each compound.

A. SiCl4 1) silicon chloride

2) tetrasilicon chloride

3) silicon tetrachloride

B. P2O5 1) phosphorus oxide

2) phosphorus pentoxide

3) diphosphorus pentoxide

C. Cl2O7 1) dichlorine heptoxide

2) dichlorine oxide

3) chlorine heptoxide

Learning Check

Write the correct formula for each of the following.

A. phosphorus pentachloride

B. dinitrogen trioxide

C. sulfur hexafluoride

Learning Check

Learning Check

Identify each compound as ionic or covalent and give its

correct name.

A. SO3

B. BaCl2

C. (NH4)3PO4

D. Cu2CO3

E. N2O4

Learning Check

Write the formulas for the following.

A. calcium nitrate

B. boron trifluoride

C. aluminum carbonate

D. dinitrogen tetroxide

E. copper(I) phosphate

Binary Acids

• A binary acid is an aqueous solution of a compound

containing hydrogen and a nonmetal.

• The formula of an acid always begins with H:

• HF (aq)

• Binary acids are named by using the prefix hydro- before

the element stem and adding the suffix -ic acid.

• HF (aq) is hydrofluoric acid.

• HI (aq) is hydroiodic acid.

Ternary Oxyacids

• Ternary oxyacids are aqueous solutions of a compound

containing hydrogen and an oxyanion.

• If the acid is derived from an oxyanion ending in -ate, the

suffix is changed to -ic acid.

• HNO3 (aq) is nitric acid (from NO3-, nitrate ion).

• If the acid is derived from an oxyanion ending in -ite, the

suffix is changed to -ous acid.

• HNO2 (aq) is nitrous acid (from NO2-, nitrite ion).

Oxyanions and Oxyacids

Below is an example of ternary oxyacid and ternary

compound naming.

Ternary Oxyacid Ternary Compound

HClO hypochlorous acid NaClO sodium hypochlorite

HClO2 chlorous acid NaClO2 sodium chlorite

HClO3 chloric acid NaClO3 sodium chlorate

HClO4 perchloric acid NaClO4 sodium perchlorate

Learning Check

Provide the name of the acid.

1. HCN =

2. H2S =

3. H3PO4 =

4. HNO2 =

5. H2SO3 =

6. HClO4 =

7. HClO =