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Nomenclature
Chemistry 1
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The Language of Chemistry
 Subscripts
indicate the number of atoms of an
element in a molecule.
C8H18
 How
or
MgCl2
many atoms of each element are in the
following?
CH4
 SO2
 O2
 P4O10
 Pb(NO3)2

+ Review
 What
is a cation?
 What
is an anion?
 What
group of elements typically form +1 cations? Why?
 What
group of elements typically form +2 cations? Why?
 What
group of elements typically form -1 anions? Why?
 What
group of elements typically form -2 anions? Why?
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Ions and Compounds

Monatomic ions (N3-)
 Ions formed from a single atom

Polyatomic ions (SO42-)
 Ions formed from more than one atom
 See hand-out (purple)
 Binary

Compounds
Made of two elements
 Ternary

Compounds
Made of three or more elements (contains polyatomic
ion)
 **When
writing chemical formulas for ionic
compounds, the overall charge of the compound must
be ZERO/NEUTRAL!**
+ Formula of Ionic Compounds
1)
List the cation (positively charged ion) chemical
symbol first.
2)
List the anion (negatively charged ion) chemical
symbol after the cation.
3)
If the charges are not the same (sum of the oxidation
numbers must equal zero), subscripts must be added
to indicate a ratio of positive and negative ions.
-The polyatomic ion acts as an individual ion.
-Because polyatomic ions act as a unit, NEVER CHANGE
SUBSCRIPTS OF ANY ATOM WITHIN THE ION.
-Transition metals with more than one oxidation number…
the charge is noted using roman numerals!
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Let’s Practice Writing Formulas
Q: What is the chemical formula for aluminum
fluoride?
1.
Symbol for aluminum ion = Al3+
Symbol for fluoride ion = F-
2. Al3+F3. Least common multiple is
4. AlF3
5. Orbital Notation Verification
.
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Practice Writing Formulas
Write the correct formula for the following ionic
compounds.
1)
Potassium and Iodide
2)
Magnesium and Chloride
3)
Aluminum and Bromide
4)
Cesium and Nitride
5)
Barium and Sulfide
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Practice Writing Formulas With
Polyatomic Ions
1)
Sodium and Nitrate
2)
Calcium and Chlorate
3)
Aluminum and Carbonate
4)
Potassium and Chromate
5)
Magnesium and Carbonate
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Naming Ionic Compounds
 List
the name of the cation (watch for transition
metals).
 List
the name of the anion, changing the ending to
“ide”
 If
you have a polyatomic anion, just list its name after
the cation.
 CaCl2
 Na2S
= calcium chloride
= sodium sulfide
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Naming Ionic Compounds With A
Transition Metal
 Work
backwards to determine the charge on the
transition metal….
Cr2O3
FeO
NiCl2
Mn3(PO4)2
Rules To Name Compound:
1. Name the cation
2. Place the charge of the transition metal as a roman
numeral
3. Name the anion by changing the ending to “ide”
+ Review – Binary Compounds
Write the correct chemical formula for each of the following
compounds.






potassium bromide
magnesium selenide
sodium phosphide
tin(IV) chloride
aluminum oxide
scandium(III) sulfide
Give the correct names for each of the following compounds listed
below.




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
KF
SnI4
SiF4
AlBr3
FeCl3
ZnO
+ Review Ternary Compounds

Write the chemical formulas for the following names:
 Iron (III) acetate
 Gold(III) sulfate
 Ammonium phosphate
 Calcium nitrate

Write the chemical names for the following chemical formulas:
 FeC2O4
 Pb(CO3)2
 Al(MnO4)3
 Ba(OH)2
+ Entrance Ticket


Write the formula for the following compounds. Hint-look
up the charges for each element/ion and then balance
the charges
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Calcium Nitride

Rubidium Sulfide
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Lead (II) Nitrate
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Iron (III) Oxide
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Manganese (III) Chlorate
Write the name for the following compounds.
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Cr3P2
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Al2 (SO4) 3

BaO
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CoN
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Cu3 (PO4 ) 2
+ Molecular Compounds
Nomenclature (Covalent)

When naming compounds consisting of two nonmetals, the names
of the elements are written in the same order as they appear in
the formula. (The more metallic element is written first.)

The second element uses the suffix “-ide”. Prefixes are added to
the name of each element to indicate the NUMBER of atoms of the
element in the molecule.
 (If the first element’s prefix is mono-, it will be dropped. For
example, monocarbon dioxide (CO2) is simply called carbon
dioxide.)

**Note: the “o” or “a” at the end of a prefix is usually dropped
when the word following the prefix begins with another
vowel…e.g. monoxide or pentoxide.
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Prefixes –Polyatomic Handout
Prefix
Number of atoms
Mono-
1
Di-
2
Tri-
3
Tetra-
4
Penta-
5
Hexa-
6
Hepta-
7
Octa-
8
Nona-
9
Deca-
10
+ For the following molecular compounds,
write the molecular formula:
 Carbon
 Sulfur
mononitride
tribromide
 Phosphorus
 Nitrogen
 Carbon
dioxide
tetrachloride
 Dihydrogen
 Sulfur
triflouride
monoxide
trioxide
 Dinitrogen
hexoxide
+ For the following molecular formulas, write the
compound name:
 SiO2
 CO2
 SeF6
 N2O5
 As2O5
 AsI3
 PCl5
 CF4
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Flow Chart Challenge
 Create
a flow chart to use while NAMING Ionic and
Covalent Compounds
 Hints:
 How
do you distinguish between an Ionic and
Covalent Compound?
 Which one uses prefixes?
 When do you use Roman Numerals in the name?
 What do you do for naming polyatomic ions?
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Chemical Formulas
Chemistry 1
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Oxidation Numbers
 “oxidation
 The
states”
number of electrons that must be added to or
removed from an atom in a combined state to convert
the atom into the elemental form.
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Assigning
Oxidation States
Rules for Assigning Oxidation States
The Oxidation State of…

An atom in an element is zero
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A monatomic ion is the same as its charge
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
HF, PF3
Oxygen is usually -2 in its compounds

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
Na+, Cl-
Fluorine is -1 in its compounds
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Na(s), O2(g), Hg(l)
H2O, CO2
Exception: Peroxides (containing O22-) in which oxygen is -1
Hydrogen is +1 in its covalent compounds

H2O, HCl, NH3
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Oxidation Numbers - Model
Assign oxidation numbers to the atoms of each element in the
following compounds.

PI3

HF

CS2

As2S3

NO2-
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Oxidation Numbers Practice
Assign oxidation numbers to the atoms of each element in the following
compounds.

CI4

HCl

SO3

IO3

H2CO3

SO42-
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Percent Composition

The percentage by mass of each element in a compound.
massofelementincompound
x100% = %ElementinCompound
massofcompound
+1.
Using the periodic table determine the molar mass
of the compound.
2.
Take each mass for each element (molar mass
times number of atoms) and divide it by the total
mass of the compound.
3.
Multiply this value by 100 to obtain a percentage.
4.
Percentages should add up to equal 100%
Steps For Calculations
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Percent Composition

Determine the percent composition in the following compounds:

PbBr4

Ba(OH)2
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Percent Composition

Determine the percent composition in the following
compounds:

NaOH

(NH4)3PO4

CCl2F2

Pb(NO3)2
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Bite the Bubble Lab

See handout
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Empirical Formula: The formula with the smallest
whole number ratio of the elements in the
compound (simplest formula)

1.

Note: May not always be the same as the molecular
formula.
To calculate, convert masses of elements to moles.
If a question gives the percentages of each compound,
assume you have 100 g of the sample and then each
percentage becomes the mass of the element.
2.
Next, divide each mole by the smallest one.
3.
This gives the ratio of atoms, which you will use to
write the formula.
Empirical Formula
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Empirical Formulas
 The
percent composition of a compound was
found to be 63.5% silver, 8.2% nitrogen, and
28.3% oxygen. Determine this compound’s
empirical formula.
 Name
the compound.
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Empirical Formulas
A
170.00g sample of a compound contains 29.84 g
sodium, 67.49 g chromium and 72.67 g oxygen. What is
the empirical formula?
 Name
the compound.
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Empirical Formula
 200.00
grams of an organic compound is known to
contain 83.884 grams of carbon, 10.486 grams of
hydrogen, 18.640 grams of oxygen and the rest is
nitrogen. What is the empirical formula of the
compound?
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Molecular
Formulas

Molecular Formulas: A formula that specifies the actual number of
atoms of each element in one molecule of the substance.
-Molecular formula is a multiple of the empirical formula.
Steps for Solving:

Determine the Empirical Formula first!

Use the formula :
molecularweight
N=
empiricalformulaweight
N= The number we will multiply the subscripts in the empirical formula
by to obtain the new molecular formula.
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Empirical and Molecular Formulas
A
compound of boron and hydrogen has a percent
composition of 78.14% boron and 21.86% hydrogen. If
the molar mass is 27.6, what is the empirical and
molecular formula?
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Empirical and Molecular Formulas
A
compound with the formula C2H5O is found to have a
molar mass of 90g. What is the molecular formula of the
compound?
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 Test
will cover…
 New
 Ionic, Molecular, and
Acid Nomenclature
 Oxidation Numbers and Percent Composition
 Empirical and Molecular Formulas
 Chemical Bonding
 Periodic Table Trends, Electron Configuration and
Periodic Table History
Chapter Review