nomenclature nomenclature – naming and rules for naming of compounds. the names of the cations of...

Nomenclature

Nomenclature – naming and rules for naming of compounds.

The names of the cations of the Group 1A, Group 2A, and Group 3A metals are the same as the name of the metal, followed by the word ion or cation.

9.1

Monatomic Ions

Anions

The charge of any ion of a Group A nonmetal is determined by subtracting 8 from the group number.

Anion names start with the stem of the element name and end in -ide.

9.1

Monatomic Ions

These Group A elements form anions.

These transition elements form cations. (They may also have more than one charge state.)

9.1

Monatomic Ions9.1

Monatomic Ions

Ions of Transition Metals

How are the charges of some transition metal ions determined?

9.1

Monatomic Ions

The charges of the cations of many transition metal ions must be determined from the number of electrons lost.

9.1

Monatomic Ions

Two methods are used to name the ions of transition metals.

• The Stock system

• The common naming system

9.1

Monatomic Ions

In the Stock system, a Roman numeral in parentheses is placed after the name of the element to indicate the numerical value of the charge.

9.1

Monatomic Ions

In the common naming system, the classical name of the element is used to form the root name for the element.

9.1

Monatomic Ions9.1

Conceptual Problem 9.1

1.1

Polyatomic Ions

Polyatomic Ions

What are the two endings of the names of most polyatomic ions?

9.1

Polyatomic Ions

These models show the structures of four common polyatomic ions.

9.1

Polyatomic Ions

Some ions, called polyatomic ions, are composed of more than one atom.

The names of most polyatomic anions end in -ite or -ate.

9.1

Polyatomic Ions

Names and Formulas of Some Common Polyatomic Ions

9.1

Binary Ionic Compounds


a. How are the names of binary ionic compounds determined?

b. How do you write the formulas for binary ionic compounds?

9.2


Naming Binary Ionic Compounds

a. A binary compound is composed of two elements and can be either ionic or molecular.

a. To name any binary ionic compound, place the cation name first, followed by the anion name.

9.2


a. Tin(II) fluoride, or SnF2, is added to toothpastes to prevent cavities.

9.2


a. Tin(IV) sulfide, or SnS22,, is used in glazes for porcelain fixtures and dishes.

9.2


Writing Formulas for Binary Ionic Compounds

a. Write the symbol of the cation and then the anion. Add whatever subscripts are needed to balance the charges.

9.2


9.2

Compounds With Polyatomic Ions

Compounds with Polyatomic Ions

How do you write the formulas and names of compounds containing polyatomic ions?

9.2


Write the symbol for the cation followed by the formula for the polyatomic ion and balance the charges.

9.2


a. For example, calcium nitrate is composed of a calcium cation (Ca2+) and a polyatomic nitrate anion (NO3–).

b. In calcium nitrate, two nitrate anions, each with a 1– charge, are needed to balance the 2+ charge of each calcium cation. The formula for calcium nitrate is Ca(NO3)2.

9.2


9.3


Naming Compounds with Polyatomic Ions

a. To name a compound containing a polyatomic ion, state the cation first and then the anion, just as you did in naming binary ionic compounds.

9.2

Naming Binary Molecular Compounds

Naming Binary Molecular Compounds

What does a prefix in the name of a binary molecular compound tell you about the compound’s composition?

9.3

a. Carbon and oxygen combine to form carbon monoxide (CO) and carbon dioxide (CO2), but these two invisible gases are very different.

9.3Naming Binary Molecular Compounds

a. Sitting in a room with small amounts of CO2 in the air would not present any problems. If the same amount of CO were in the room, you could die of asphyxiation. A naming system that distinguishes between these two compounds is needed.


a. A prefix in the name of a binary molecular compound tells how many atoms of an element are present in each molecule of the compound.


a. Some guidelines for naming binary molecular compounds:

a. Name the elements in the order listed in the formula.

b. Use prefixes to indicate the number of each kind of atom.


a. Omit the prefix mono- when the formula contains only one atom of the first element in the name.

b. The suffix of the name of the second element is -ide.


Writing Formulas for BinaryMolecular Compounds

Writing Formulas for Binary Molecular Compounds

a. How do you write the formula for a binary molecular compound?

9.3

a. Use the prefixes in the name to tell you the subscript of each element in the formula. Then write the correct symbols for the two elements with the appropriate subscripts.

9.3Writing Formulas for BinaryMolecular Compounds

a. Silicon carbide is a hard material like diamond. The name silicon carbide has no prefixes, so the subscripts of silicon and carbon must be one. Thus, the formula for silicon carbide is SiC.

9.3Writing Formulas for BinaryMolecular Compounds

Naming and Writing Formulas for Acids and Bases

Some ants can give painful stings when threatened or disturbed. Certain ant species called formicines have poison glands that produce venom containing formic acid. You will learn the names and formulas of some important acids such as formic acid.

9.4

Naming Acids

Naming Acids

What are the three rules for naming acids?

9.4

a. An acid is a compound that contains one or more hydrogen atoms and produces hydrogen ions (H+) when dissolved in water. Acids have various uses.

9.4Naming Acids

a. Three rules can help you name an acid with the general formula HnX.

a. When the name of the anion (X) ends in -ide, the acid name begins with the prefix hydro-. The stem of the anion has the suffix -ic and is followed by the word acid.

9.4Naming Acids

Naming Acids

When the anion name ends in -ite, the acid name is the stem of the anion with the suffix -ous, followed by the word acid.

9.4

When the anion name ends in -ate, the acid name is the stem of the anion with the suffix -ic followed by the word acid.

9.4Naming Acids

a. A Summary of the Three Rules for Naming Acids.

9.4Naming Acids

Writing Formulas for Acids

Writing Formulas for Acids

How are the formulas of acids determined?

9.4

a. Use the rules for writing the names of acids in reverse to write the formulas for acids.

a. What is the formula for hydrobromic acid? Following Rule 1, hydrobromic acid (hydro- prefix and -ic suffix) must be a combination of hydrogen ion (H+) and bromide ion (Br–). The formula of hydrobromic acid is HBr.

9.4Writing Formulas for Acids

9.4Writing Formulas for Acids

Names and Formulas for Bases

How are bases named?

9.4Names and Formulas for Bases

a. Bases are named in the same way as other ionic compounds—the name of the cation is followed by the name of the anion.

a. For example, aluminum hydroxide consists of the aluminum cation (Al3+) and the hydroxide anion (OH–). The formula for aluminum hydroxide is Al(OH)3.


a. Sodium hydroxide (NaOH) is a base that is used to make paper.


a. Cleaners and soap contain sodium hydroxide.


The Laws of Definite and Multiple Proportions


a. What are the two laws that describe how compounds form?

9.5

a. The rules for naming and writing formulas for compounds are possible only because compounds form from the elements in predictable ways.

a. These ways are summed up in two laws: the law of definite proportions and the law of multiple proportions.


9.5

The Law of Definite Proportions

a. The law of definite proportions states that in samples of any chemical compound, the masses of the elements are always in the same proportions.


9.5

a. Water obeys the law of definite proportions. In every sample of water, the mass ratio of oxygen to hydrogen is always 8:1.


9.5

a. Hydrogen peroxide obeys the law of definite proportions. The mass ratio of oxygen to hydrogen is always 16:1.


9.5

The Law of Multiple Proportions

a. The law of multiple proportions: Whenever the same two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole numbers.


9.5

a. A Diagram of the Law of Multiple Proportions


9.5

Practice Problems for Sample Problem 9.1

Practicing Skills: Naming Chemical Compounds

a. How do you use a flowchart to write the name of a chemical compound?


9.5

Follow the arrows and answer the questions on the flowchart to write the correct name for a compound.


9.5


9.5

a. CuSO4 is an example from the flowchart. The compound will end in -ite or -ate. Cu is not part of Group A, so you must name the ions and use a Roman numeral to identify the charge of the transition metal. The name is copper(II) sulfate.


9.5

Practicing Skills: Writing Chemical Formulas

a. What four guidelines should you follow to write the formula of a chemical compound?

9.4Practicing Skills: Naming Chemical Compounds

a. In writing a chemical formula from a chemical name, it is helpful to remember the following guidelines.

a. An -ide ending generally indicates a binary compound.

b. An -ite or -ate ending means a polyatomic ion that includes oxygen is in the formula.


9.5

a. Prefixes in a name generally indicate that the compound is molecular.

b. A Roman numeral after the name of a cation shows the ionic charge of the cation.


9.5


9.5

nomenclature nomenclature – naming and rules for naming of compounds. the names of the cations of...

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