ANIONS: Atoms that have gained electrons and have a negative charge -Nonmetals form anions CA+IONS:...
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Transcript of ANIONS: Atoms that have gained electrons and have a negative charge -Nonmetals form anions CA+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
Ion: A Charged AtomBy gaining or losing electrons, atoms become
ions.
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.
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!
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.
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!
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