ANIONS: Atoms that have gained electrons and have a negative charge

-Nonmetals form anions

CA+IONS: Atoms that have lost electrons and have a positive charge

-Metals form cations

Ion: A Charged AtomBy gaining or losing electrons, atoms become

ions.

Group # 1 2 13 14 15 16 17 18

Oxid. #

OXIDATION NUMBERS ARE PERIODIC

Monatomic Ions: 1 Atom Ions

• To Name:– Positive Monatomic Ions: Name the metal, if

it is a transition metal, add a Roman Numeral to indicate the number of the charge

– Negative Monatomic Ions: Change the ending of the elements name to –ide

Example--Name the following:

Cu+1 Ca+2 Cl-

Polyatomic Ions: More than 1 atom ions

Polyatomic Ions end in –ate or –ite and are found in the chart at the bottom of your periodic table…just look them up

Examples: Name the following

CO32- OH-

Write the formulas of the following:

Nitrite Perchlorate

What do opposites do?

A metal will lose electrons to become stable. What charge will that metal have after it loses electrons?

A nonmetal will gain electrons to become stable. What charge will that nonmetal metal have after it gains electrons?

If metal ions are in a container with nonmetal ions…What will happen?

ATTRACT

- (Nonmetals form negative ions)

ATTRACT—Come together in an ionic bond

+ (Metals form positive ions)

Ionic Bond

• The strong attractive force between ions of opposite charge. Occurs when one atom transfers electrons to another atom to become stable

• Electrons are transferred in an ionic bond.

• Ionic bonds form between metals and nonmetals

EMPIRICAL FORMULA

• Chemical formula for an ionic compound

• Lowest whole number ratio of ions in an ionic compound

EMPIRICAL FORMULA

Al2O3

Subscript: # written to the lower right of a chemical symbol that shows the number of atoms of that element present in the compound

Because compounds are all _____________ in charge, the total sum of the oxidation numbers in a compound must be ________.

Determine the number of each ion necessary so that the sum of the charges is 0.

1Using oxidation numbers to determine the empirical formula of a compound.

Write the symbol of charge of each ion in the compound

Crisscross each ions numerical charge down to the subscript of the other ion Can check your answer—the charges will still add up to be 0

2Using the crisscross method to determine the empirical formula of an ionic compound.

Sr3N2

Sr+2 N3-

Naming Ionic Compounds Make sure it is an ionic compound. How can you tell?

Determine if it’s a binary or a ternary ionic compound. Binary = Ternary =

Ternary compounds contain a ____________________

Ionic compounds will have only _________words in their names. This is because all ionic compounds are composed of just 1 ____________ and just 1 ______________. If the compound has more than 2 elements than one of

the ions is a ______________________________ ion.

It contains a metal & nonmetal(s) or ammonium & nonmetal(s).

2 elementsMore than 2 elements

Polyatomic ion

2

cation anion

Polyatomic ion

Naming a Binary Ionic CompoundTo Name an Ionic Compound CaCl2 Fe2O3 Na2O

Name the metal

If the metal is a transition metal, add a Roman numeral in parentheses to indicate it’s charge

Name the nonmetal, changing its suffix to –ide

EXAMPLESTo Name an Ionic Compound CuCl MnO AlBr3

Name the metal

If the metal is a transition metal, add a Roman numeral in parentheses to indicate it’s charge

Name the nonmetal, changing its suffix to -ide

Naming a Ternary Ionic Compound

To Name an Ternary Ionic Compound

CaSO4Cu(C2H3O2)2 NH4OH

Does the formula begin with NH4? If so the first word is ammonium. If not, name the metal

If the metal is a transition metal, add a Roman numeral in parentheses to indicate it’s charge

Name the polyatomic ion.

Naming a Ternary Ionic Compound

To Name an Ternary Ionic Compound

Al(ClO)3 KSCN NaHCO3

Does the formula begin with NH4? If so the first word is ammonium. If not, name the metal

If the metal is a transition metal, add a Roman numeral in parentheses to indicate it’s charge

Name the polyatomic ion.

ExamplesName the following ionic compounds.LiCl Ca(OH)2 (NH4)2S

KI CoO Ni(NO3)2

IONIC VS. COVALENT BONDING

IONIC COVALENT

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Molecular Compounds Molecular compounds form when elements

__________________ electrons to form compounds. Also known as covalent compounds. How can you distinguish a molecular

compound from an ionic compound based on its chemical formula or chemical name?

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Ionic Compounds are made of metals combined with nonmetals. Molecular compounds are made of all nonmetals!

Which type of bond would form between the following elements?

MgCl2 CI4 AlN

CO2 OF2 SnO2

Molecule A group of atoms united by covalent bonds

Polyatomic Ions are molecules that have charge!

DIATOMIC MOLECULES: Some elements only exist in nature as molecules consisting of 2 atoms of that element.

•Why? More stable as a pair!

•The 7 diatomic elements are: HONClBrIF

Molecular Substance Substance made of molecules

Molecular Formula Tells how many atoms of an element are in a single molecule of a

compound The chemical formula of a covalent compound is not the lowest whole

number ratio Different from an EMPIRICAL FORMULA which gives the lowest whole

number ratio of ions in an IONIC COMPOUND

To Name a Molecular Compound Name the 1st element. If there is more

than one of that element, use the appropriate prefix (mono- is not used on the first element)

Name the last element using the appropriate prefix and changing its ending to –ide. Since there are no metals in molecular

compounds, no Roman numerals are used.

NUMERICAL PREFIXES1 Mono-

2 Di-

3 Tri-

4 Tetra-

5 Penta-

6 Hexa-

7 Hepta-

8 Octa-

9 Nona-

10 Deca-

ExamplesN2O4

PCl5

NO2

Dinitrogen tetroxide

Phosphorous pentachloride

Nitrogen dioxide

Chemical Formulas for Molecular Compounds Use the prefixes to determine the chemical

formula Since molecular compounds do not involve the

transfer of electrons, there are no ions—do not get charges and no crisscrossing!

ExamplesNitrogen trifluoride

Diphosphorus pentoxide

Carbon tetrachloride

NF3

P2O5

CCl4

HYDRATES An ionic compound that

contains water within its crystal structure Anhydrous: A compound in

which all water has been removed.

The water may be evaporated off of a hydrate to leave the anhydrous form of the substance

HYDRATESTo Identify a hydrate

BaCl2 3H2O barium chloride trihydrate

To Name a hydrate Name the ionic compound followed by the word hydrate with

a prefix to indicate the # of water molecules attached. MgSO4 2H2O

To Write the Formula for a Hydrate Use the crisscross method to determine the formula of the

ionic compound, followed by a dot, followed by the # of water molecules indicated by the prefix. Copper(II) chloride pentahydrate

Acids A molecular substance that

dissolves in water to produce H+ ions

The chemical formula starts with H (we will assume all are dissolved in water)

To Name a Binary Acid “Hydro”-root name of anion-“ic Acid”

Ex: Hydrobromic Acid

To Name an Acid containing a Polyatomic Ion Root name of Polyatomic Ion- “ic” Acid

Ex: Sulfuric Acid

To determine the formula of an acid Consider Hydrogen an Ion: H+

Determine the charge of the anion Crisscross charges

H+ S2- H2S