Naming Ions Monatomic Ions Ions consisting of a single atom with a + or - charge Anions (-) Most from 5A, 6A, 7A Naming: Start with the stem of the element’s

Naming IonsNaming Ions

Monatomic Ions

Ions consisting of a single atom with a + or - charge

Anions (-)

Most from 5A, 6A, 7A

Naming: Start with the stem of the element’s name ending with -ide

Example: Fluoride, Chloride, Nitride

Cations (+)

Most from Groups 1A, 2A, 3A

Naming: Same as the name of the metal, followed by ion or cation

Example: Sodium Ion, Potassium Ion

Naming halogen compoundsNaming halogen compounds

When combined with other elements in simple compounds the name of the halogen element changes slightly from ...ine to ...ide.

Fluorine forms a fluoride (ion F-), chlorine forms a chloride (ion Cl-), bromine a bromide (ion Br-) and iodine an iodide (ion I-).

The other element at the start of the compound name e.g. hydrogen, sodium, potassium, magnesium, calcium, etc. remains unchanged.

So typical halogen compound names are, potassium fluoride, hydrogen chloride, sodium chloride, calcium bromide, magnesium iodide etc.

The elements all exist as X2 or X-X, diatomic molecules where X represents the halogen atom.

Naming Ions

Transition Metals*Charges must be determined by the number of electrons lost*Can have varying charges for the same elements

*Naming: Two MethodsStock System: Roman numerals in parenthesesExample: Fe2+

Written: Iron(II) ion

Read: “Iron two ion,”

Example: Fe3+

Written: Iron(III) ion

Read: “iron three ion”

Naming Ions

Transition Metals

Classical System: suffix used with root name to name the ion

Example: Fe2+

Written: Ferrous Ion

Example: Fe3+

Written: Ferric Ion

Example: Cr2+

Written: Chromous Ion

Example: Cr3+

Written: Chromic Ion

Naming IonsTransition Metals

-Classical System: some names may seem unfamiliar

-Iron: Ferr-

-Copper: Cupr-

-Tin: Stann-

-Lead: Plumb-

-Some transition metals have only one charge

Ag+

Cd2+

Zn2+

Naming IonsPolyatomic Ions

Ions composed of more than one atom

Tightly bound groups of atoms that behave as one unit and have a charge

All Anions ending in -ite or -ate contain Oxygen

“-ites” have one less oxygen than “-ates”

Examples: ClO2- Chlorite

ClO3- Chlorate

Cr2O72- Dichromate

PO33- Phosphite

Naming Ions

Polyatomic Ions

When a polyatomic ion contain Hydrogen, it is like adding a H+ with another polyatomic ion

Examples: H+ + CO32- ----> HCO3

-

Carbonate Hydrogen Carbonate

H+ + PO43- ----> HPO4

2-

Phosphate Hydrogen Phosphate

Ionic BondsIonic Bonds

Bonds between ions

Based on “opposites attract”

Cation + Anion (+) charge (-) charge

(metals) (nonmetals)

NamingNaming

Chemical name + Chemical name of cation of anion PLUS

“ide” ending

Example: Na+ + Cl-

NaCl Sodium chloride (capitalized) (not capitalized)

Unlike atoms, compounds are stable when they are neutral

There is no way to know from the name how many atoms of each kind are present

in an ionic compound

Therefore, the chemical formula is needed to determine the number of each atom

necessary for a reaction to occur

Chemical Name Sodium chloride

Swap charges Na1+ + Cl1- superscript =

charge on ion

Na1 + Cl1 subscript =

number of atoms

needed to form the compound

Chemical Formula NaCl

Naming and Writing FormulasBinary Ionic Compounds

An ionic or molecular compound composed of two elements

Antoine-Laurent Lavoisier developed a naming system w/ other chemists

Naming: Place the cation first followed by the anion.

Formula: Cation first, Anion second

Remember, total charge equals zero!

Example: Cs2O = Cesium Oxide (Ionic)

CuO = Copper(II) Oxide (Ionic) Hint: 1:1 ratio

Naming and Writing FormulasBinary Ionic Compounds

Naming and Writing FormulasCompounds with Polyatomic Ions

Recall that a Polyatomic Ion acts as one unit

Naming: Place the cation first followed by the anion.

Formula: Cation first, Anion second

Example: PbSO4 = Lead(II) Sulfate

K2HPO4 = Potassium Hydrogen Phosphate

Naming and Writing Formulas

Compounds with Polyatomic Ions

Naming and Writing FormulasNaming Binary Molecular Compounds

The prefix tells how many atoms of each element are present in each molecule of the compound

Carbon Monoxide vs. Carbon Dioxide

Mono- indicates one oxygen

Di- indicates two oxygens

Naming and Writing FormulasGuidelines for Naming

1) Confirm the compound is a molecular compound (2 nonmetals)

2) Omit mono- when the the formula contains only one of the first element in the name

3) Add -ide to the second element in the formula

Guidelines for Formula Writing

1) Use the prefixes in the name to tell you the subscripts in the formula


Practice

Write the name of these molecular compounds:

a) NCl3

b) BCl3

c) NI3

d) SO3

e) N2H4

f) N2O3


Practice

Write the formulas for these binary molecular compounds:

a) Phosphorus pentachloride

b) Iodine heptafluoride

c) Chlorine trifluoride

d) Iodine dioxide

e) Carbon tetrabromide

f) Diphosphorus trioxide


Acids

A compound that contains one or more hydrogen atoms and produces hydrogen ions (H+) when dissolved in water

Acids consist of an anion and as many H+ as are necessary to make the atom electrically neutral.

HnX


Naming Acids

1) When the anion’s name ends in -ide, the acid’s name begins with hydro- and the stem of the anion’s name ends in -ic, followed by the word acid.

Example: Hydrochloric Acid HCl

Anion: Chloride Cl-


Naming Acids

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

Example: Sulfurous Acid H2SO3

Anion: Sulfite SO32-


Naming Acids

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

Example: Nitric Acid HNO3

Anion: Nitrate NO3-

Naming and Writing FormulasWriting Formulas for Acids

Use the rules for naming acids in reverse to write formulas for acids.

Find the anion in the acid. Then, match its charge with the appropriate number of H+ ions to make the formula electrically neutral.


Names and Formulas for Bases

An ionic compound that produces hydroxide ions (OH-) when dissolved in water.

These are named in the same way as other ionic compounds: cation first and anion second.

Common Bases

NaOH Sodium Hydroxide

Ba(OH)2 Barium Hydroxide

Ca(OH)2 Calcium Hydroxide

The Laws Governing Formulas and Names

The Laws of Definite Proportions

In samples of any compound, the masses of the elements are always in the same proportions

Example:

100 g of MgS has 43.13 g of Mg and 56.87 g of S

Ratio: 0.758/1


The Laws 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

Example: 16 g of O in H2O2 to every 1 g of H = 2:1

8 g of O in H2O to every 1 g of H



Carbon and Oxygen can form two compounds.

A: contains 2.41 g of C for every 3.22 g of O

B: contains 6.71 g of C for every 17.9 g of O

A: 2.41 g of C/3.22 g of O = 0.748 g C/g O

B: 6.71 g of C/17.9 g of O = 0.375 g C/ g O

0.748 g/0.375 g = 1.99/1 = about 2:1



Naming Chemical Compounds


Naming Chemical Compounds

Guidelines:

1) -ide generally indicates a binary compound

2) -ite or -ate means a polyatomic ion that includes O

3) Prefixes generally indicate a molecular compound

4) A Roman numeral shows the charge of the cation

Documents

Naming Ions Monatomic Ions Ions consisting of a single atom with a + or - charge Anions (-) Most from 5A, 6A, 7A Naming: Start with the stem of the element’s