Download 01 Names and Formulas PPT

Names & Formulas
Nomenclature
Over 6 million
compounds have been
identified.
Each one has a unique
name and formula.
All compounds are
neutral.
I. 3 Categories of Compounds
1) Ionic:
Used to name ionically
bonded atoms.
Made up of metals plus
non-metals.
2) Molecular:
Used to name covalently
bonded atoms.
Made up of non-metals.
3) Acids and Bases:
All traditional acids begin
+
with the hydrogen ion (H ).
All traditional bases end
with hydroxide ion (OH ).
II. Ionic Compounds
Contain IONIC bonds.
Form between metals and nonmetals.
Ions combine in small, whole
number ratios.
They are ALWAYS NEUTRAL
A. Binary Ionic Compounds
“Binary” means two.
Binary ionic compounds contain only
two elements.
Their names always end in “ide”.
Writing Formulas of Binary Ionic
Compounds
1. Write + and - ions.
2. Reduce oxidation numbers if
needed.
3. “Criss-cross” oxidation numbers
(without signs) to become
subscripts within the formula
Example #1
sodium chloride
First, write the ions: Na+1 + Cl-1
Next, write the formula by crisscrossing oxidation numbers so
that they become the subscripts
of the other ion: Na1Cl1
Formula is NaCl
Example #2
Calcium chloride
First, write ions: Ca+2 + Cl-1
Next, criss cross oxidation
numbers without signs to
become subscripts within
formula: Ca1Cl2
CaCl2
Example #3
Magnesium nitride
+2
-3
Write ions: Mg + N
Criss-cross
Mg3N2
Naming Binary Ionic Compounds
Cations (+) retain the name of the
element.
Anions (-) keep the root name but
add “ide” ending.
Example #1
LiF
lithium fluoride
Example #2
SrCl2
strontium chloride
Example #3
Al2O3
aluminum oxide
B. Multi-Charge Metals
Most of the transition metals have
variable oxidation numbers.
Roman numerals are used to indicate
charges of these elements.
First, look at the total negative charge
of the anion (oxidation number x
number of atoms).
Then, use this information to determine
the oxidation number of the metallic
cation.
Example #1
FeO
First, look at anion to determine total
negative charge:
-2 (oxidation #) x 1 (# of atoms) = -2
Total positive charge must be +2 because all
molecules are neutral.
When you look at formula, you see the ratio
of Fe to O is 1:1
Fe2+ + O2iron (II) oxide
Example #2
Fe2O3
Total charge on anion:
-2 x 3 = -6
Total charge on cation: +6
? x 2 = +6
? = +3
Fe3+ + O2iron(III) oxide
Example #3
Copper (I) Oxide
Cu1+ + O2Cu2O
These are easy because the
Roman numeral in the name
gives you the charge of the
cation!
Example #4
Copper (II) Oxide
Cu2+ + O2CuO
IMPORTANT EXCEPTIONS to
MEMORIZE!
Silver always forms a +1 ion.
Zinc always forms a +2 ion.
Cadmium always forms a +2
ion.
The oxidation numbers of lead
and tin also vary.
STOP
Do
Binary Ionic
Compounds HW
Ternary Ionic Compounds
C. Ternary Ionic Compounds
Contain three or more elements
Contain at least one polyatomic
ion
Writing Formulas and
Naming
Ternary Ionic Compounds
Follow the same rules and
complete the same steps as for
binary ionic compounds
Enclose PAI in parentheses when
necessary
Example #1
Aluminum phosphate
Write ions: Al
3+
+ PO4
3-
Reduce oxidation numbers then
criss-cross: Al1 (PO4 )1
AlPO4
Example #2
Sodium sulfate
Na
1+
+ SO4
Na2SO4
2-
Example #3
Iron (II) bromate
Fe2+ + BrO3Fe3(BrO)2
Example #4
CaCO3
calcium carbonate
Example #5
Cu(NO3)2
Remember copper is a
transition metal!
copper(II) nitrate
Example #6
(NH4)3N
ammonium nitride
STOP
Do
Ternary Ionic Compounds
HW
Molecular Compounds
III. Molecular Compounds
•Contain COVALENT bonds.
•The same elements can combine in
various ways.
•PREFIXES are used to tell them
apart.
A. Binary Molecular Compounds
Binary compounds contain two
different elements.
Binary compounds always end in
“ide” .
We will only learn BINARY molecular
compounds.
Prefixes:
1 = mono
2 = di
3 = tri
4 = tetra
5 = penta
6 = hexa
7 = hepta
8 = octa
9 = nona
10 = deca
To name:
Use prefixes on first
atom, except for “mono”.
Always use prefixes on
the last atom.
Change ending to “ide”.
Examples
S2O3 is disulfur trioxide
CO is carbon monoxide
OF2 is oxygen difluoride
To write formulas:
Look at prefixes attached to each
element to determine subscript.
Examples:
Arsenic pentiodide = ArI5
Carbon dioxide = CO2
Diphosphorus trioxide = P2O3
B. Hydrocarbons
Molecular compounds that
contain only carbon and
hydrogen
Alkanes have single bonds
Alkenes have double bonds
Alkynes have triple bonds
Alkanes
carbon chain held together
with single bonds.
Generic Formula: CxH(2x + 2)
Naming Alkanes
Based on number of carbons
in molecule (prefixes indicate
#)
All end in “ane”.
Prefixes for Alkanes
Meth = 1
Eth = 2
Prop = 3
But = 4
Pent = 5
Hex
Hept
Oct
Non
Dec
=
=
=
=
=
6
7
8
9
10
Mice Eat Peanut Butter
Meth
Eth
Prop
But
Examples
Ethane is C2H6
Heptane is C7H16
STOP
Do
Molecular Compounds
And
Hydrocarbons
HW
IV. Acids and Bases
Acids are easy to recognize
because they begin with “H”.
Bases are easy to recognize
because they end with “OH” .
A. Bases
The anion in bases is always
the hydroxide ion.
Because they are ionic, you
already know how to name
them (there are no special
rules)
Examples
NaOH
sodium hydroxide
KOH
potassium hydroxide
B. Binary Acids
Have only two elements:
hydrogen and a nonmetal.
Naming Binary Acids
1)Use the prefix “hydro”
2) Add the suffix “ic”
Examples:
HCl is hydrochloric acid
H3N is hydronitric acid
To write formulas:
+1
H
1) Start with
2) End with negative ion
(nonmetal) from periodic table
3) “Criss-Cross”
Examples:
Hydroiodic acid = HI
Hydrophosphoric acid = H3P
C. Ternary Acids
Have at least three elements:
H and a polyatomic ion
Naming Ternary Acids
1) DO NOT use “hydro” prefix!
2) Add suffix:
if “ate” ion, use “ic” suffix
if “ite” ion, “ous” suffix
Examples #1
HClO3
ClO31- is chlorate (ate = ic)
chloric acid
Example #2
H2SO3
SO32- is sulfite (ite = ous)
sulfurous acid
To write formulas:
1) Start with H 1+
2) End with negative polyatomic
ion
3) “Criss-Cross”
Examples:
perchloric acid (ic = ate)
Perchlorate is ClO4-1
All acids start with H+1
HClO4
chlorous acid (ous = ite)
Chlorite is ClO2-1
All acids start with H+
HClO2
STOP
Do
Names and Formulas
Of Acids
HW