By gaining or losing electrons, atoms become ions. Ion: A Charged Atom By gaining or losing electrons, atoms become ions. 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

OXIDATION NUMBERS ARE PERIODIC Group # 1 2 13 14 15 16 17 18 Oxid. #

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

+ (Metals form positive ions) ATTRACT 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? + (Metals form positive ions) - (Nonmetals form negative ions) ATTRACT—Come together in an ionic bond

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

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

Using the crisscross method to determine the empirical formula of an ionic compound. 2 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 Sr+2 N3- Sr3N2

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 elements More than 2 elements Polyatomic ion 2 cation anion Polyatomic ion

Naming a Binary Ionic Compound To 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

To Name an Ionic Compound EXAMPLES To 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 CaSO4 Cu(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.

Examples Name the following ionic compounds. LiCl Ca(OH)2 (NH4)2S KI CoO Ni(NO3)2

IONIC VS. COVALENT BONDING www.blobs.org/science/article.php?article=17Remove frame 

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? share 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 Molecular Formula Substance made of molecules 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 PREFIXES 1 Mono- 2 Di- 3 Tri- 4 Tetra- 5 Penta- 6 Hexa- 7 Hepta- 8 Octa- 9 Nona- 10 Deca-

Examples N2O4 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!

Examples Nitrogen 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

HYDRATES To 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 an Acid containing a Polyatomic Ion 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