How are the following words related?
ouro
zlato
de oro
aurum
• All are the word for the element
“gold” in Portuguese, Croatian,
Spanish, and Latin
CHAPTER 9
p. 252
CHEMICAL NAMES AND
FORMULAS
SECTION 9.1 p. 253
NAMING IONS
• Atoms - neutral
•same # + and e• Ions are atoms, or groups of
atoms, with a charge (positive or
negative)
•different # + and e• gain or lose e-’s
• Monotomic Ions – 1 atom w/ + or
- charge
A Cation is…
+
ion formed by losing e-’s
 Metals lose e-’s
 Charge written as superscript
An Anion is…
• - ion
1+e-’sHas lost one electron (no
• gains
name change for positive ions)
• Nonmetals can gain e-’s
K
2+
Ca
Has lost two electrons
Ion
High
School
Predicting Ionic Charges
Group 1A: Lose 1 e- to form 1+ ions
H1+ Li1+
Na1+
K1+ Rb1+
Predicting Ionic Charges
Group 2A: Loses 2 e-’s to form 2+ ions
Be2+ Mg2+ Ca2+ Sr2+ Ba2+
Predicting Ionic Charges
B3+
Al3+
Ga3+
Group 3A: Loses 3
e-’s to form
3+ ions
Predicting Ionic Charges
Neither! Group 4A
elements rarely form
ions (they tend to share)
Group 4A: Do they
lose 4 e-’s or gain 4
e-’s?
Predicting Ionic Charges
N3-
Nitride
P3-
Phosphide
As3- Arsenide
Group 5A: Gains 3
e-’s to form
3- ions
Predicting Ionic Charges
O2-
Oxide
S2-
Sulfide
Se2- Selenide
Group 6A: Gains 2
e-’s to form
2- ions
Predicting Ionic Charges
F1- Fluoride
Cl1- Chloride
Group 7A: Gains
Br1- Bromide 1 e- to form
I1- Iodide
1- ions
Predicting Ionic Charges
Group 8A: Stable
noble gases do not
form ions!
Predicting Ionic Charges
Group B elements: Many transition elements
have more than one possible oxidation state.
2+
Iron
(II)
=
Fe
Roman numerals show
Iron (III) = Fe3+
charges
Naming cations
1) Stock system – Roman
numerals in () indicates
numerical value
2) Classical method – root
word w/ suffixes (-ous, -ic)
• Doesn’t give true value
Naming cations
• Stock system.
• Cation - if the charge is always the
same (like in the Group A metals) just
write the name of the metal.
• Transition metals can have more than
one charge.
• Indicate their charge as Roman numeral
in () after name of cation (Table 9.2,
p.255)
Predicting Ionic Charges
Some of the post-transition elements also
have more than one possible oxidation state.
Tin (II) = Sn2+
Lead (II) = Pb2+
Tin (IV) = Sn4+
Lead (IV) = Pb 4+
Predicting Ionic Charges
Group B elements: Some transition elements
have only one possible oxidation state, such
as these three:
Silver = Ag1+
Zinc = Zn2+
Cadmium = Cd2+
Exceptions:
• Some transition metals have only
one ionic charge:
•Do not use Roman numerals
for these:
• Silver always 1+ (Ag1+)
• Cadmium and Zinc always 2+
(Cd2+ and Zn2+)
Practice by naming these:
• Na1+
• Ca2+
• Al3+
• Fe3+
• Pb2+
• Li1+
Write symbols for these:
• Potassium ion
• Magnesium ion
• Copper (II) ion
• Chromium (VI) ion
• Barium ion
• Mercury (II) ion
Naming Anions
•Change monatomic element
ending to – ide
1•F a Fluorine atom becomes
Fluoride ion.
Practice by naming these:
1•Cl
3•N
•Br1•O2-
Write symbols for these:
•Sulfide ion
•Iodide ion
•Phosphide ion
Polyatomic ions
• Groups of atoms that stay together and have overall
charge
• Usually end in –ate or -ite
• Acetate:
• Nitrate:
C2H3O21-
NO31-
NO211• Permanganate: MnO4
• Nitrite:
• Hydroxide:
OH1- and Cyanide: CN1-?
Know Table 9.3 on page 257
2-
PO43• Phosphite: PO33• Phosphate:
SO4
• Sulfite: SO32• Carbonate: CO321+
•
Ammonium:
NH
4
• Chromate: CrO42(One of the few positive
• Dichromate: Cr2O72polyatomic ions)
• Sulfate:
If polyatomic ion begins with H, then combine the word
hydrogen with the other polyatomic ion present:
H+ + CO32- →
HCO3hydrogen + carbonate → hydrogen carbonate ion
Section 9.2 – Marble madness
• Pair up with someone
• everyone gets a cup
• The person in each pair whose birthday
is closest to today gets to add 4 marbles
in their cups
• The other person keeps an empty cup
• Listen for further instructions
SECTION 9.2
P. 260
NAMING & WRITING FORMULAS
FOR IONIC COMPOUNDS
Example: Barium nitrate (note the 2 word name)
1. Write the formulas for
cation and anion, including
CHARGES!
2. Do charges balance?
2+
(
Ba NO3 ) 2
3. Balance charges , if necessary,
Now balanced.
using subscripts. Use () if more than Not balanced!
one polyatomic ion. Use criss-cross = Ba(NO3)2
method to balance subscripts.
Writing Ionic Compound Formulas
Example: Ammonium sulfate (note the 2 word name)
1. Write the formulas for
cation and anion, including
CHARGES!
( NH4+) SO42-
2. Do charges balance?
3. Balance charges , if necessary,
using subscripts. Use () if more than
one polyatomic ion. Use criss-cross
method to balance subscripts.
2
Now balanced.
Not balanced!
= (NH4)2SO4
Writing Ionic Compound Formulas
Example: Iron (III) chloride (note the 2 word name)
1. Write the formulas for
cation and anion, including
CHARGES!
Fe3+ Cl-
2. Do charges balance?
3. Balance charges , if necessary,
using subscripts. Use () if more than
one polyatomic ion. Use criss-cross
method to balance subscripts.
3
Now balanced.
Not balanced!
= FeCl3
Writing Ionic Compound Formulas
Example: Aluminum sulfide (note the 2 word name)
1. Write the formulas for
cation and anion, including
CHARGES!
2. Do charges balance?
3. Balance charges , if necessary,
using subscripts. Use () if more than
one polyatomic ion. Use criss-cross
method to balance subscripts.
3+
Al
2
2S
3
Now balanced.
Not balanced!
= Al2S3
Writing Ionic Compound Formulas
Example: Zinc hydroxide (note the 2 word name)
1. Write the formulas for
cation and anion, including
CHARGES!
2+
Zn
2. Do charges balance?
3. Balance charges , if necessary,
using subscripts. Use () if more than
one polyatomic ion. Use criss-cross
method to balance subscripts.
( OH- )2
Now balanced.
Not balanced!
= Zn(OH)2
Naming Ionic Compounds
• 1. Name cation first, then anion
• 2. Monatomic cation = name of element
Ca2+ = calcium ion
• 3. Monatomic anion = root + -ide
Cl- = chloride
CaCl2 = calcium chloride
Naming Ionic Compounds
(Metals with multiple oxidation states)
• some metals form more than one
charge (usually transition metals)
• use Roman numeral in name:
PbCl2 – use anion to find charge on
cation (chloride always 1-)
Pb2+ is lead (II) cation
PbCl2 = lead (II) chloride
Things to look for:
1) If cation has ( ), the number in
parenthesis is its charge.
2) If anion ends in –ide, likely
monoatomic
3) If anion ends in -ate or –ite, it’s
polyatomic
Practice by writing formula or name
• Iron (II) Phosphate
• Stannous Fluoride
• Potassium Sulfide
• Ammonium Chromate
• MgSO4
• FeCl3
Section 9.3 p. 268
Naming and Writing Formulas for Molecular
Compounds
Molecular cmpds…
•made of nonmetals
•smallest piece… molecule
•not bound by opposite charge attraction
•can’t use charges to figure # of each atom
(no charges present)
Molecular v.s. Ionic Compounds
• Ionic: use charges to determine # of
each
• Molecular:
name tells you # of
atoms
• prefix tells exact # of each element
Know these prefixes (Table 9.4 p. 269)
Prefix Mono Di Tri Tetra Penta Hexa Hepta Octa Nona deca
Value
1 2 3 4
5
6
7
8
9 10
Formula Elements # atoms
N2O
PBr5
P4S3
CS2
IF7
prefixes
Using Prefixes to name covalent
compounds
• To write the name, write two words:
Prefix name Prefix name -ide
• One exception…..don’t write
mono
when only one of first element
Using Prefixes to name covalent
compounds
• 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.
• Normally, we do not have double vowels when writing
names (oa oo)
Practice by naming these:
• NO2
= nitrogen dioxide
• Cl2O7
• CBr4
= dichlorine heptoxide
= carbon tetrabromide
• CO2
= carbon dioxide
• BaCl2
(This one will not use prefixes, since it is
an ionic compound!)
Write formulas for these:
• diphosphorus pentoxide
• tetraiodine nonoxide
• phosphorus trifluoride
• carbon tetrahydride
• sulfur hexafluoride
more SF6
Section 9.4 p. 271
Naming and Writing Formulas for Acids
and Bases
Acids are…
•Cmpds containing 1 or more H atoms
& produces H ions (H1+) when dissolved
in H2O
•Chem formula starts with H followed by
anion
•anion determines acid name
Rules for Naming acids: Name it as
normal cmpd first
1) If anion ends in –ide:
1) Acid name begins w/ prefix hydro2) change -ide to -ic acid
• HCl(aq) - hydrogen ion and
chloride ion = hydrochloric acid
• H2S(aq) hydrogen ion and sulfide
ion = hydrosulfuric acid
Naming Acids
•
If anion has O, it ends in -ate or -ite
2) change suffix -ate to -ic acid (no prefix)
• If you “ate” something acidic, you would probobaly say “ic”!
• Example: HNO3 Hydrogen and nitrate ions =
Nitric acid
3) change the suffix -ite to -ous acid (no prefix)
• Example: HNO2 Hydrogen and nitrite ions =
Nitrous acid
Anion ending
Example
Acid name
Example
-ide
Chlor ide, Cl -
Hydro-(stem)-ic
acid
Hydrochloric
acid
-ite
Sulf ite, SO3 2-
(stem)-ous acid
Sulfurous acid
-ate
Nitrate, NO3 -
(stem)-ic acid
Nitric acid
Naming Acids
Normal ending
Acid name is…
____-ide
hydro-___-ic acid
____-ate
_____-ic acid
____-ite
_____-ous acid
Practice by naming these:
• HF
• H3P
• H2SO4
• HCN
• H2CrO4
Write formulas for these:
• hydroiodic acid
• acetic acid
• carbonic acid
• phosphorous acid
• hydrobromic acid
Names and Formulas for Bases
• A base is ionic cmpd producing
hydroxide ions (OH1-) when
dissolved in water
• Bases named same way as other
ionic cmpds:
• Name of cation (which is a metal)
followed by name of anion (hydroxide)
Names and Formulas for Bases
•
NaOH - sodium hydroxide
• Ca(OH)2 - calcium hydroxide
• To write the formula:
1) Write symbol for metal cation
2) followed by formula for hydroxide
ion (OH1-)
3) use criss-cross method to balance
charges
Practice by writing the formula for
the following:
•Magnesium hydroxide
•Iron (III) hydroxide
•Zinc hydroxide
Practice by naming the following
bases:
•NaOH
•NH4OH
•Ca(OH)2
•Al(OH)3
Section 9.5 p. 274
The Laws Governing Formulas
and Names
• Review: Law of Conservation of Mass?
• Mass neither created or destroyed but is
conserved during any chem rxn
Mass reactants = mass products
Mass cmpd = mass of SUM of elements
in cmpd
Law of Definite Proportions
• 1. Law of Definite Proportions (mass) -
in a sample of a pure cmpd, masses of
elements always in same proportions
• CO2 (carbon dioxide)
• CO (carbon monoxide)
Law of Multiple Proportions
(Dalton’s Law)
• 2. Law of Multiple Proportions-
Dalton stated whenever 2 elements
form more than one cmpd, the
different masses of 1 element that
combine with the same mass of the
other element are in the ratio of
small whole numbers
- Page 275
Same mass
of oxygen
Law of definite and multiple proportions
Guided Practice Problem 34 p. 275 (p. 90
#34 in workbook)
p. 275 practice problem #34
Lead forms two compounds with oxygen. One compound
contains 2.98 g of Pb and 0.461 g of O. The other contains
9.89 g of Pb and 0.763 g of O. For a given mass of
oxygen, what is the lowest whole number mass ratio of
lead in the two compounds?
Step 1. Write the ratio of lead to oxygen for each cmpd.
______g Pb
9.89 g Pb
0.461 g O
______g O
Step 2. Divide the numerator by the denominator in
each ratio.
6.46 ______
_______g Pb
_________
gO
Step 3. Write a ratio comparing the first compound to
the second.
_____ g Pb/g O
13.0 g Pb/g O
Step 4. Simplify. Note that this ratio has no units (they
cancel out)
0.497
= roughly 1
1
__
The mass ratio of lead per gram of oxygen in the two
compounds is:
Summary of Naming and Formula
Writing
• Naming formulas – flowchart -
Figure 9.20, page 277
• Writing formulas – flowchart -
Figure 9.22, page 278
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 is the ionic charge of
the cation