nomenclature

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nomenclature
Writing a molecular formula
• The oxidation numbers of the elements or
polyatomic molecules involved must add
up to zero
• Review pg. 221 if you can’t remember
oxidation numbers.
• You must know the polyatomic ions on
THE HANDOUT I GAVE YOU
Formation of Ionic Compounds
• Remember that objects with opposite charges
attract each other.
• The strong attractive force between ions of
opposite charge is called an ionic bond.
• Don’t forget that even though the ions have
charges, the overall charge of the compound will
be …
• ZERO!
Polyatomic Ions
• Polyatomic ions are groups of covalently
bonded atoms that have a charge
• For example:
• SO4 -2
• NO3 –1
• ClO3 –1
• NH4 +1
Polyatomic Ions
• Writing formulas with polyatomic ions is
the same.
• You just have to keep the polyatomic ions
grouped together
• The charges need to cancel out, so you’re
going to have to do a little multiplication.
• you MUST use parentheses with
polyatomics!
Formula writing with polyatomic
Ions
• Write the formula for the compound
formed between sodium and nitrate
• Na +1 NO3 -1 (the charges cancel so….)
• Na(NO3)
Formula writing with polyatomic
Ions
• Write the formula between ammonium and
sulfate
• NH4 +1 SO4 -2 (charges don’t cancel….)
• So multiply by the smallest common factor
to get the charges to cancel.
• (NH4)2 (SO4)
Formation of Ionic Compounds
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Don’t Forget!
• Some elements oxidation numbers can not
be predicted
• elements can form multiple charges
• Roman numerals will tell you the charge!
• For example: Copper (II)  Cu +2
More examples
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Copper (II) and chlorine
Silver and Nitrate
Magnesium and sulfite
Calcium and sulfur
Potassium and oxygen
Ammonium and phosphate
Ammonium and chlorine
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CuCl2
AgNO3
MgSO3
CaS
K2O
(NH4)3PO4
NH4Cl
Multiple Charges to Remember
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Copper
Iron
Lead
Tin
Manganese
Gold
Cobalt
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+1 and +2
+2 and +3
+2 and +4
+2 and +4
+2, +4, and +7
+1 and +3
+1 and +2
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Mg+2 combined with PO4-3 =
Mg3(PO4)2
K+1 combined with SO4-2 =
K2SO4
• Write the molecular formulas for :
• Ammonium nitrate
» NH4NO3
• Iron (III) oxide
– Fe2O3
• Barium hydroxide
– Ba(OH)2
Nomenclature• The scientific process of naming
compounds in chemistry.
• Ionic compounds- are composed of ions
combined so that the net charge equals
zero. The positive ion is always named
first. These are usually found in a one to
one ratio.
Naming ionic compounds
• In naming ionic compounds, name the
cation first, then the anion.
• Monatomic cations use the element name.
• Monatomic anions use the root of the
element name plus the suffix -ide.
• (This means 1 element with a negative
charge will end in –ide).
Naming ionic compounds
• If an element can have more than one
oxidation number, use a Roman numeral
in parentheses after the element name, for
example, iron(II) to indicate the Fe 2+ ion.
• For polyatomic ions, use the name of the
ion.
Oxyanions
• Certain polyatomic ions, called
oxyanions, contain oxygen and another
element.
• If two different oxyanions can be formed
by an element, the suffix -ate is used for
the oxyanion containing more oxygen
atoms, and the suffix -ite for the oxyanion
containing fewer oxygens.
Examples
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NaCl
MgSO4
K3PO4
Ca(ClO3)2
NH4NO2
Al(ClO)3
CuSO3
Fe(NO3)2
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Sodium chloride
Magnesium sulfate
Potassium phosphate
Calcium chlorate
Ammonium nitrite
Aluminum hypochlorite
Copper (II) sulfite
Iron (II) nitrate
Molecules
• Molecule – two or more atoms covalently
bound together
• Diatomic molecule – two of the same
atom bound together
Diatomic Molecules
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Br I N Cl H O F or the Magnificent 7
These atoms never exist alone.
They always come in pairs
For example:
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Br  Br2
I  I2
N  N2
Cl  Cl2
H  H2
O  O2
F  F2
Naming Binary Covalent
Compounds
• Before you can name binary covalent
compounds, you MUST know the prefixes!
Prefixes
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Mono
Di
Tri
Tetra
Penta
Hexa
Hepta
Octa
Nona
Deca
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1
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5
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Rules for naming Binary Covalent
Compounds
• Name the prefix for the number of atoms
of the first element
• Then name the first element
• Name the prefix for the number of atoms
of the second element
• Than name the root of the second element
with the ending -ide
Note…
• No charges are used in Binary Covalent
Compounds
• If the 1st prefix is mono….DROP IT!
• When the prefix ends in an o or a, and the
name of the element begins with a vowel,
the o or a is often dropped
Examples
• What is the name of N2O4?
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N2  di
nitrogen
O4  tetra oxide
Since oxide begins with a vowel, we will
drop the a in tetra
Dinitrogen tetroxide
More examples
• Name SO2
 S  mono sulfur
 But mono is with the 1st element, so it will be
dropped  sulfur
 O2  dioxide
 Sulfur dioxide
More examples
• Write the formula for dichlorine monoxide
 Dichlorine  Cl2
 Monoxide  O
 Cl2O
More examples
• Write the formula for disulfur dichloride
 Disulfur  S2
 Dichloride  Cl2
 S2Cl2
Acids
• Acids can be recognized because the start
with H
• Examples
– HCl
– H2SO4
– HI
Acids
• - Follow their own rules. Most if not all
acids contain H.
• The binary acids always begin with the
prefix hydro.
• The stem comes from the other atom
involved.
• They always end in ic.
Rule #1 - naming acids
• If the anion ends in –ide, the acid will be
named…
• Hydro (root) – ic acid
• This is usually for H plus one element
For example
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HCl
Hydrochloric acid
HI
Hydroiodic acid
H2S
Hydrosulfuric acid
• Complex Acids or Oxyacids- do not ever
have a prefix.
• Formed from polyatomic ions that have an
O in them.
• ate polyatomics form acids and their
ending changes to ic
• ite polyatomic ions end in ous
Rule #2 – naming acids
• If you have an H plus an anion ending in –
ate, the acid will be named…
• (root) – ic acid
Examples
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H2SO4
Sulfuric acid
HNO3
Nitric acid
H3PO4
Phosphoric acid
Rule # 3 – naming acids
• If you have an H plus an anion ending in –
ite, the acid will be named…
• (root) – ous acid
Examples
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H2SO3
Sulfurous acid
HNO2
Nitrous acid
H3PO3
Phosphorous acid
Remember…
ate  ic
ite - ous
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Mixed examples
(remember to figure out what type of
compound it is 1st!)
KClO2
CO2
H2SO4
NH4Br
CuCO3
Fe2O3
HClO
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Potassium chlorite
Carbon dioxide
Sulfuric acid
Ammonium bromide
Copper (II) carbonate
Iron (III) oxide
Hypochlorous acid
More Mixed Examples
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Carbon tetrachloride
Phosphorous pentachloride
Aluminum oxide
Copper (II) nitrate
Chlorous acid
Hydrophosphoric acid
Iron (III) hydroxide
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CCl4
PCl5
Al2O3
Cu(NO3)2
HClO2
H3P
Fe(OH)3
More examples
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H2SO3
H2CO3
HF
Nitrous acid
Perchloric acid
Iodic acid
Phosphorous acid
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Sulfurous acid
Carbonic acid
Hydrofluoric acid
HNO2
HClO4
HIO3
H3PO3
Organic Notes
• Nomenclature- a system used to name
compounds
• Hydrocarbons• Organic chemistry uses prefixes and
suffixes to name compounds
• Prefixes tell how many carbons are in the
chain
• Ex; meth = 1
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Eth = 2
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Prop = 3
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But = 4
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Pent = 5
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Hex = 6
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Hept = 7
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Oct = 8
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Non = 9
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Dec = 10
• Suffixes tell what type of bond the
compound has
• Ane = single bond
• Ene = double bond
• Yne = triple bond
• There will be only one of these bonds in
the compound.
• Cyclo = when the the carbon chain forms a
ring
• Ex; cyclopropane is
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Branched Chain Alkanes•
When all the carbons in the
hydrocarbon molecule are not bonded in a
straight line they are called branched
chains. They are named based on the
following rules:
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Determine the longest continuous chain
of carbon atoms = parent chain.
Number thru parent chain so that the first
branch is closest to the lowest number.
Name the branched groups by changing
the ane ending to yl.
Use the prefixes di and tri for multiple
branched groups.
• EX:
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CH2CH3 CH2CH3
CH3CH2CHCH2CHCHCH3
CH2CH3
CH2CH3 CH2CH3
CH3CH2CHCH2CHCHCH3
CH2CH3
Concept 7 organic notes
• A conjugated system is when multiple p
orbitals overlap, see pg. 717 These are
very stable systems, much more stable
than other unsaturated systems.
• Isomers- two or more compounds with the
same molecular formula. See. Pg 718
• Structural isomers – a re-arrangement of
the carbon chain.
• Positional isomers – when an atom other
than C or H can occupy more than 1
position.
• Functional isomers- when a functional
group can occupy more than one position.
• Geometric isomers- when the
arrangement of atoms on either side of a
multiple bond can be altered.