Transcript Chapters 8 & 9 - DocLockert.com

Chapters 8 & 9
Naming Compounds
Writing Formulas
Compounds
Follow the Law of Definite Proportion.
 Have a constant composition.
 Have to add the same number of atoms
every time.
 Two types.

Two Types of Compounds
1 Ionic Compounds
Made of cations and anions.
 Metals and nonmetals.
 The electrons lost by the cation are
gained by the anion.
 The cation and anions surround each
other.
 Smallest piece is a FORMULA UNIT.

Crystalline Structure –
Ionic Compound
Two Types of Compounds
2 Molecular Compounds
Made of molecules.
 Made by joining nonmetal atoms
together into molecules.
 H2O, CO2, C6H12O6

Chemical Formulas
 Shows
the kind and number of
atoms in the smallest piece of a
substance.
 Molecular formula- number and
kinds of atoms in a molecule.
 CO2
 C6H12O6
Two Types of Compounds
Smallest
Piece
Types of
Elements
State
Melting
Point
Ionic
Molecular
Formula Unit
Molecule
Metal and
Nonmetal
Nonmetals
Solid
High >300ºC
Solid, Liquid
or Gas
Low <300ºC
Chemical Formulas
than one atom? –use a
subscript (H2O)
 There are 7 diatomic elements
 Hydrogen (H2), Nitrogen (N2),
Oxygen (O2), Fluorine (F2),
Chlorine (Cl2), Bromine (Br2), and
Iodine (I2)
 Remember: “Br I N Cl H O F”
 More
+1
+2
+3
-3 -2 -1
Systematic Naming
 There
are too many compounds to
remember the names of them all.
 Compound is made of two or more
elements.
 Put together atoms.
 Name should tell us how many and
what type of atoms.
Naming Ions
We will use the systematic way.
 Cation- if the charge (oxidation #) is
always the same, use name of the
metal.
 Transition metals can have more than
one charge or oxidation number.
 Therefore, indicate the charge with
roman numerals in parenthesis.
 Fe+3 is named - iron (III) ion Movie

Exceptions:
 Some
of the transition metals have
only one ionic charge:
–Do not use roman numerals for
these:
–Silver is always 1+ (Ag1+)
–Cadmium and Zinc are always 2+
(Cd2+ and Zn2+)
Metals with Multiple Charges
Transition Metals
Here it is easier to list the ones that only
have a single common oxidation state.
All Group 3B - 3+
Ni, Zn, Cd - 2+
Ag
- 1+
Lanthanides and actinides - 3+
Name These Ions
Na+1
 Ca+2
 Al+3
 Fe+3
 Fe+2
 Pb+2
 Li+1

sodium ion
calcium ion
aluminum ion
iron (III) ion
iron (II) ion
lead (II) ion
lithium ion
Write Formulas for These
Potassium ion
 Magnesium ion
 Copper (II) ion
 Chromium (VI) ion
 Barium ion
 Mercury (II) ion

K+1
Mg+2
Cu+2
Cr+6
Ba+2
Hg+2
Naming Anions
Anions are always the same.
 Change the element ending to – ide
 F-1 Fluorine

Naming Anions
Anions are always the same.
 Change the element ending to – ide
 F-1 Fluorin

Naming Anions
Anions are always the same
 Change the element ending to – ide
 F-1 Fluori

Naming Anions
Anions are always the same
 Change the element ending to – ide
 F-1 Fluor

Naming Anions
Anions are always the same
 Change the element ending to – ide
 F-1 Fluori

Naming Anions
Anions are always the same
 Change the element ending to – ide
 F-1 Fluorid

Naming Anions
Anions are always the same
 Change the element ending to – ide
 F-1 Fluoride

Name These Ions
Cl-1
 N-3
 Br-1
 O-2
 Ga+3

Chloride
Nitride
Bromide
Oxide
Gallium (III)
Write These
sulfide ion
 iodide ion
 phosphide ion
 strontium ion

S-2
I-1
P-3
Sr+2
Polyatomic Ions
Groups of atoms that stay together and
have a charge.
 Use your reference sheet


Acetate C2H3O2-1

Nitrate NO3-1
Nitrite NO2-1
 Hydroxide OH-1
 Permanganate MnO4-1
 Cyanide CN-1

Polyatomic Groups with a
Charge
Polyatomic Ions

Sulfate SO4-2

Sulfite SO3-2

Carbonate CO3-2
Chromate CrO4-2
 Dichromate Cr2O7-2
-3
 Phosphate PO4
 Phosphite PO3-3


Ammonium NH4+1
Common Polyatomic Ions
Ionic Compounds
We’ve named the ions, so now
it is time to name the
compounds!
Naming Binary Ionic Compounds
Binary Compounds - 2 elements.
 Ionic - a cation and an anion.
 To write the names just name the two
ions.
 Easy with Representative elements.
 NaCl = Na+ Cl- = sodium chloride
+2 Br- = magnesium bromide
 MgBr2 = Mg

Naming Binary Ionic Compounds
The problem comes with the transition
metals.
 Need to figure out their charges.
 The compound must be neutral.
 Same number of + and – charges.
 Use the anion to determine the charge
on the positive ion.

Balancing Charges
Zn
2
P
3
How many zinc +2 charges are needed to
balance phosphide’s -3 charge?
What subscripts must be placed on the line?
The numbers used must always be whole
numbers.
Zn3 P2
Naming Ionic Compounds
Many metals form more than one compound with
some anions.
For these, roman numerals are used in the name
to indicate the charge on the metal.
Cu1+
+
O2copper(I)
oxide
Cu2+
+
O2copper(II)
oxide
= Cu2O
copper(I) oxide
= CuO
copper(II) oxide
More Examples
Note
FeCl2
FeCl3
iron(II) chloride
iron(III) chloride
SnS
SnS2
tin(II) sulfide
tin(IV) sulfide
AgCl
CdS
silver chloride
cadmium sulfide
Some transition metals only have a single state
so the roman numeral may be omitted.
Some main group metals, with high atomic number
have more than one state, roman numbers are used.
Naming Binary Ionic Compounds
Write the name of CuO
 Need the charge of Cu
 O is -2
 Copper must be +2
 Copper (II) oxide
 Name CoCl3
 Cl is -1 and there are three of them = -3
 Co must be +3 Cobalt (III) chloride

Naming Binary Ionic Compounds
Write the name of Cu2S.
 Since S is -2, the Cu2 must be +2, so
each one is +1.
 copper (I) sulfide
 Fe2O3
 Each O is -2
3 x -2 = -6
 2 Fe must = +6, so each is +3.
 iron (III) oxide

Naming Binary Ionic Compounds
Write the names of the following
 KCl
Potassium Chloride
 Na3N
Sodium Nitride
 CrN
Chromium (III) Nitride

Sc3P2
 PbO
Scandium (II) Phosphide
PbO2
 Na2Se
Lead (IV) Oxide


Lead (II) Oxide
Sodium Selenide
Ternary Ionic Compounds
Will have polyatomic ions
 At least three elements
 Name the ions
 NaNO3
Sodium Nitrate
 CaSO4
Calcium Sulfate
 CuSO3
Copper (II) Sulfite
 (NH4)2O
Ammonium Oxide

Ternary Ionic Compounds
LiCN
 Fe(OH)3
 (NH4)2CO3
 NiPO4

Lithium Cyanide
Iron (III) Hydroxide
Ammonium Carbonate
Nickel (III) Phosphate
Writing Formulas
The charges have to add up to zero.
 Get charges on pieces.
 Cations from name of table.
 Anions from table or polyatomic.
 Balance the charges by adding
subscripts.
 Put polyatomics in parenthesis.

Writing Formulas
Write the formula for calcium chloride.
 Calcium is Ca+2


Chloride is Cl-1
Ca+2 Cl-1 would have a +1 charge.
 Need another Cl-1
 Ca+2 Cl2-1

Write the Formulas for These
lithium sulfide
 tin (II) oxide
 tin (IV) oxide
 magnesium fluoride
 copper (II) sulfate
 iron (III) phosphide
 gallium (I) nitrate
 iron (III) sulfide

Li2S
SnO
SnO2
MgF2
CuSO4
FeP
GaNO3
Fe2S3
Write the Formulas for These
ammonium chloride
 ammonium sulfide
 barium nitrate

NH4Cl
(NH4)2S
Ba(NO3)2
Things To Look For
If cations have (roman #), the number is
their charge.
 If anions end in -ide they are probably
off the periodic table (Monoatomic)
 If anion ends in -ate or -ite it is
polyatomic

Molecular Compounds
Writing Names and Formulas
Molecular Compounds
made of just nonmetals
 smallest piece is a molecule
 can’t be held together because of
opposite charges
 can’t use charges to figure out how
many of each atom

Easier
Ionic compounds use charges to
determine how many of each.
– Have to figure out charges.
– Have to figure out numbers.
 Molecular compounds name tells you
the number of atoms.
 Uses prefixes to tell you the number

Prefixes
1 mono 2 di 3 tri 4 tetra 5 penta 6 hexa 7 hepta 8 octa
Prefixes
9 nona 10 deca To write the name write two words

Prefixes
9 nona 10 decaTo write the name, write two words with

Prefix name Prefix name -ide
Prefixes
9 nona 10 deca To write the name write two words

Prefix name Prefix name -ide

One exception is we don’t write mono- if
there is only one of the first element.
Prefixes
9 nona 10 deca To write the name write two words

Prefix name Prefix name -ide
One exception is we don’t write mono- if
there is only one of the first element.
 No double vowels when writing names
(oa oo)

Name These
N2O
 NO2
 Cl2O7
 CBr4
 CO2
 BaCl2

Dinitrogen Monoxide
Nitrogen Dioxide
Dichlorine Heptoxide
Carbon Tetrabromide
Carbon Dioxide
Barium Chloride
Write Formulas for These
diphosphorus pentoxide
 tetraiodine nonoxide
 sulfur hexafluoride
 nitrogen trioxide
 carbon tetrahydride
 phosphorus trifluoride
 aluminum chloride

P2O5
I4O9
SF6
NO3
CH4
PF3
AlCl3
Nomenclature Flowchart
Is a metal present
Use prefixes
as the first element? No (mono, di, tri ...)
Yes
Can the metal have
more than one
oxidation state?
Yes
Use Roman numerals
No
Roman numerals
are not needed.
Helpful to remember...
1. In an ionic compound, the net ionic
charge is zero (criss-cross method)
2. An -ide ending generally indicates a
binary compound
3. An -ite or -ate ending means there is
a polyatomic ion that has oxygen
4. Prefixes generally mean molecular;
they show the number of each atom
Helpful to remember...
5. A Roman numeral after the name of
a cation shows the ionic charge of
the cation.
Acids
Writing Names and Formulas
Acids
Compounds that give off hydrogen ions
when dissolved in water.
 Must have H in them.
 Will always be an H next to an anion.
 The anion determines the name.

Typical Acids and Bases
Acid
HCl
Base
NaOH
HNO3
H2SO4
H3PO4
KOH
Ba(OH)2 Al(OH)3
Naming Acids
If the anion attached to hydrogen ends
in -ide, use the prefix hydro- and
change -ide to -ic
acid
 HCl - hydrogen ion and chloride ion
 hydrochloric acid
 H2S hydrogen ion and sulfide ion
 hydrosulfuric acid

Naming Acids
If the anion has oxygen in it, no hydro
 It ends in -ate or -ite
 Change the suffix -ate to -ic acid
 HNO3 Hydrogen and nitrate ions
 Nitric acid
 Change the suffix -ite to -ous acid
 HNO2 Hydrogen and nitrite ions
 Nitrous acid

Oxyanion and Oxyacids
An ion with oxygen in it is called an
oxyanion.
 An acid with an oxyanion in it is called
an oxyacid.

Name
These
HF
 H3P
 H2SO4
 H2SO3
 HCN
 H2CrO4
 H3PO4

Hydrofluoric acid
Hydrophosphoric acid
Sulfuric acid
Sulfurous acid
Hydrocyanic acid
Chromic acid
Phosphoric acid
Writing Formulas
Hydrogen will always be first
 Name will tell you the anion
 Make the charges cancel out
 Starts with hydro- no oxygen, -ide
 No hydro, -ic comes from -ate, -ous
comes from -ite

Write Formulas for These
hydroiodic acid
 acetic acid
 carbonic acid
 phosphoric acid
 hydrobromic acid

HI
HC2H3O2
H2CO3
H3PO4
HBr
More Acid Practice
Name and Formula
Name the Formula
H2S
 H2CrO4
 HClO3
 H2CO3
 HSCN
 H2SO3
 H3PO4

Hydrosulfuric acid
Chromic acid
Chloric acid
Carbonic acid
Thiocyanic acid
Sulfurous acid
Phosphoric acid
Write the Formula
Hydroiodic acid
 Hydrobromic acid
 Perchloric acid
 Sulfuric acid
 Hydrophosphoric acid
 Hydroselenic acid
 Chlorous acid

HI
HBr
HClO4
H2SO4
H3P
H2Se
HClO2