Download Document

Chem I - Chemical Formulas and Nomenclature
Name: ________________________ Period_____
I. Names of Elements
 The most common source for element names is a property of the elements.
o EX: nitrogen: Greek for nitron (niter) and genes (to be born). Niter was the name for any
naturally occurring substance that contained nitrogen.
 Some elements get their name from their place of discovery, person of honor, or from the mineral from
which they are obtained.
o Ex: Einsteinium or Berkelium
II. Chemical Symbols
 Chemical symbols of the elements are shorthand of the elements.
 J. J. Berzelius, a Swedish chemist, is generally given credit for creating the modern symbols for the
elements.
 Symbols correspond to the first letter of the name or the first two letters
if needed to distinguish between elements with the same first letter.
 In some cases, the Latin form of the element was used.
o EX:
 ________________is Fe for ferric
 All elements will begin with a capital letter. If there is a second letter, it is lowercase so that you
differentiate between elements and compounds or molecules
o EX: Cs = ________________
CS = ____________________
III. Chemical Formulas
 A chemical formula is a combination of symbols that represents the composition of a compound.
 Chemical symbols are used to indicate types of elements present.
 Subscripts are used to indicate the number of atoms for each element present.
 Coefficients are used to indicate the total number of molecules present.
C8H18




2C8H18
_____ atoms of carbon
_____ atoms of hydrogen
Total # of atoms (_______)



________ atoms of carbon
________ atoms of hydrogen
Total # of atoms (________)
Oxidation Numbers of Monatomic Ions
o The charge on a monatomic ion is the same thing as its oxidation number.
o Because atoms want to reach an octet of valence electrons, the oxidation numbers, positive and
negative charges, can be predicted for single atoms (__________________).
o Metals tend to have positive oxidation numbers.
(________________e-)
o Nonmetals tend to have negative oxidation numbers. (_______________ e-)
1

Predicting Ionic Charges
 Group 1: Lose 1 electron to form 1+ ions
 H+ Li+ Na+ K+
 Group 2: Loses 2 electrons to form 2+ ions
 Be2+ Ng2+ Ca2+ Sr2+ Ba2+
 Group 13: Loses 3 electrons to form 3+ ions
 B3+ Al3+ Ga3+
 Group 14: Lose 4 electrons or gain 4 electrons?
 ___________! Group 14 rarely form ions.
 Group 15: Gains 3 electrons to form 3- ions
 N3- (nitride) P3- (Phosphide) As3- (Arsenide)
 Group 16: Gains 2 electrons to form 2- ions
 O2- (Oxide) S2-(Sulfide) Se2-(Selenide)
 Group 17: Gains 1 electron to form 1- ions
 F1-(Fluoride) Br1- (Bromide) Cl1-(Chloride) I1-(Iodide)
 Group 18: Stable Noble gases ______________ form ions!
 Groups 3-12, Transition Elements:
 Some transition elements have only one possible oxidation state.
o ______________= Zn2+ _____________= Ag+
 Many transition elements have more than one possible oxidation state.
o Iron(II) = Fe2+
Iron(III)= Fe3+
 The oxidation number of a transition element can be determined by:
o The Roman numeral indicating the oxidation.

EX: iron (II) is Fe+2
iron (III) is Fe+3

Oxidation Numbers of Polyatomic Ions
o ____________________ ions are ions that are made up of two or more atoms.
o Refer to table of Polyatomic ions.
o Polyatomic ions generally have the following endings: “ate” or “ite”
o EX:
 (NO2)- _________________
 (PO4)-3 _________________

Oxidation Numbers in a Compound
o Compounds are formed by ions.

_______________
+
+
Na
+
Cl-
______________
NaCl
=
Compound
o A _________________ compound requires an equal number of positive and negative charges
o The sum of the oxidation numbers in a compound must equal _______________.

EX:


EX:

CaCl2 =
2 positive charges – 2 negative charges = 0
Ba+2 has an oxidation of +2, Cl- has an oxidation of -1
Therefore the formula would be: BaCl2
2
IV. Writing Ionic Formulas
 Remember:
o Ionic compounds are composed of metals and nonmetals.
o Ionic compounds are made from the gaining or losing of electrons and the resulting
electrostatic force that holds the ions together.
o The sum of the oxidation numbers in a compound must equal zero.
o When writing formulas, the Cation (metal ion) is always written ___________ the Anion
(nonmetal ion).
o When using polyatomic ions, refer to the charge.
 There is only one polyatomic Cation: NH4+ that we will focus on.
 The remaining are polyatomic Anions.
o You can determine the formulas of ionic compounds when given the only the name.
EX:
Sodium chloride
Elements:
sodium and chlorine
Oxidation:
+1
-1
# of each needed
for 0 oxidation:
1
1
(+1
+ -1 = 0)
Formula:
•
____________
EX:
Magnesium Iodide
Elements:
Magnesium and Iodine
Oxidation:
+2
-1
# of each needed
for 0 oxidation: 1
2
(+2 + -2 = 0)
Formula:
_________________
Now, let’s include polyatomic ions.
EX:
Sodium hydroxide
Elements:
Sodium (Na) and Hydroxide(OH)
Oxidation:
+1
-1
# of each needed
For 0 oxidation:
1
1
( +1
+
-1 = 0)
Formula:
EX:
Elements:
Oxidation:
# of each needed
For 0 oxidation:
Formula:
____________
Aluminum sulfate
Aluminum(Al) and Sulfate(SO4)
+3
-2
2
(+3 + +3 + -2 + -2 + -2)
+6 + -6 = 0
________________
3
3
V. Criss Cross Method of Writing Formulas
 Notice a trend between the between the oxidation/charges of ions and the subscripts of elements.
o EX:
Mg+2 and Cl- gives
 ____________
o EX:
Al+3 and SO4-2 gives
_____________

This method crosses charges and subscripts to form neutral compounds.
Draw the arrows showing the bonding below.
o Ex:
Al +3 and O-2
Al2O3
(neutral)
o EX: Lead (II) phosphate
Pb+2 and PO4 -3
Pb3(PO4)2
(neutral)

Steps in using the Criss Cross Method of Writing Formulas
1. Write the oxidation numbers of each element or polyatomic ion.
2. Determine if the charges cancel each other, if so write the formula as a one-to-one ratio.
o
Na+ Cl- = ____________
o
Ca+2 SO4-2 = ___________
3. If the charges don’t cancel each other, apply the criss-cross method.
o
Na+ P-3 = __________
o
Ca+2 PO4-3 = ______________
o Remember to put parenthesis around polyatomic ions if there will be more than one of them.

Learning Check
Circle the correct formula for the compounds containing the following ions:
1. Na+, S2a) NaS
b) Na2S
c) NaS2
2. Al3+, Cl-1
a) AlCl3
3. Mg2+, N3- a)MgN
b)AlCl
c) Al3Cl
b)Mg2N3
c) Mg3N2
4
VI. Nomenclature
 Nomenclature is defined as a _________________ system.
 Chemistry uses nomenclature to standardize names of chemicals.
VII. Naming Binary Ionic Compounds
 Naming binary (composed of _____________) ionic compounds.
 Name of cation is given first. The name of the cation is the same as the element.
 Name of anion is given last. The name of the anion is the same as the element, but with an
“____________” suffix.
EX:

Al2O3
Aluminum and Oxygen
_______________
cation
anion
Naming Ionic Compounds containing Transition Metals
o If the cation is a transition metal, such as _________(Sn) and ____________(Pb), it can have
more than one oxidation number.
o So, figure out the cation’s charge and use the roman numerals.
o Make sure to put the roman numerals in parenthesis after the name of the cation.
EX:
Pb+2 = ____________(II)
Sn+4 = ____________(IV)
Cu+1 = _____________(I)

Transition Metals with One Oxidation
o We only use the Roman Numeral System for those metals with more than one _____________.
o Transition elements with only one possible oxidation will be named with the name of the metal
only.
 _____________ (can only be +2)
 _____________ (+1)
 _____________ (+2)

Naming Ionic Compounds – Learning Check
EX:
_______________ is Silver Chloride
______________ is
Zinc oxide
_______________ is Calcium bromide
_______________ is
Sodium oxide
5

Naming Ternary Ionic Compounds
o Ternary Compounds contain a ______________________ ion.
1. Write name of cation as it is on the periodic table (or poly-ion sheet)
2. Write the name of the poly-ion as it’s written on the sheet – don’t change the ending.

o EX:
Al2(SO4)3 = _______________________
o EX:
Mg(OH)2 = _______________________
Naming Ionic Compounds – Learning Check
o Li2CO3 _________________
o FeO is ________________
o Ba(OH)2 ________________
o Sn(NO3)4 ______________
o Zn(NO3)2 _______________
o CuCl _________________
o KClO3 is _________________
o MnSO4 __________________
VII. Writing/Naming Molecules
 Remember:
o Molecules are substances that are covalently bonded together.
 They contain a nonmetal bonded to a nonmetal
o How can you tell the difference between a polyatomic ion and a molecule?
 Poly-ions have a charge when not bonded to a metal – ex. (PO4)3- or K3PO4
 Molecules contain only nonmetals and __________ overall charge – ex. P2O3

In order to be effective in naming molecules, these prefixes must be committed to memory:
1. Mono-
Molecular Prefixes
6. hexa-
2. Di-
7. hepta-
3. Tri4. Tetra-
8. octa9. Nona-
5. Penta-
10. Deca-
6
 To name binary molecules, follow these rules:
1. The less __________________ element is given first. It is given a prefix if it contributes more than
one atom to the molecule.
2. The second element is named by combining
a. (a) a prefix indicating the number of atoms contributed by the element,
b. (b) the root of the name of the second element, and,
c. (c) the ending ____________.
3. The ________ or ________ at the end of a prefix is usually dropped when the word following the
prefix begins with another vowel.
 EX:
_______________ or ______________ instead of
monooxide or pentaoxide
 EX:
P4O10
o P is less e-neg and it has more than one atom in this molecule.
_____________________
o O is named by combining prefix, root name, and ide ending.
____________________ (a is dropped from prefix)
*combine to form: Tetraphosphorus decoxide
 Naming Binary Molecules – Learning Check
EX:

SO3 is _________________
ICl3 is ____________________
PBr5 is ________________________
H20 is ____________________
Writing Binary Molecules
Now… let’s look at writing the molecular formula from the name.
 When writing the formula of a molecule, an atom’s prefix is its subscript.
 Do not cross anything.
 When there is only one of the first atom, a prefix is __________________
o Example #1
 Sulfur trioxide = _____________
o Example #2
 dichlorine heptaoxide = ________________
o Example #3

phosphorus pentachloride = _______________
o Example #4
 dinitrogen monoxide = __________________
7
o Example #5

carbon monoxide = _________________
o Example #6

dinitrogen trisulfide = _______________
VIII: Writing/Naming Acids



Acids are molecular compounds that contain ______________ bonded to a nonmetal or to a group of
polyatomic.
Acids can be either _____________or ________________ compounds.
o Names of binary acids have the form
 Hydro-_______ acid
o Names of ternary acids use a series of prefixes and suffixes to specify the number of oxygen atoms in
the molecule.
Naming Binary Acids
EX: Binary acid:
Try:


HF is ____________________________
HCl is ___________________________
H2S
_____________________

HI
_____________________


HBr
_____________________
Remember this! It
helps
Naming Ternary Acids
o
o
o
When naming ternary acids, identify polyatomic ion in the formula.
For polyions that end in “_____” change the ending to “_____”. (Something I “ate” made me feel “ic”).
For polyions that end in “_____” change the ending to “______”.(A snake b“ite” is poison“ous”)

EX:
nitrate  _________________
nitrite  _________________
sulfite  _________________
sulfate __________________

Naming Ternary Acids with four Oxygen Possibilities
o
o
o
Some ternary acids have more than one oxygen possibilitiy.
When naming ternary acidse from plyions that have up to four oxygen possibilities:
For polyions that end in “_____” change the ending to “______”.(A snake b“ite” is poison“ous”)
 -ic  greatest # of oxygen atoms.

-ic  greater # of oxygen atoms.

-ous  smaller # of oxygen atoms.

-ous  smallest # of oxygen atoms.
*Know all form of ClO3-1and IO3-1
8
Polyion
Acid Formula
Acid Name
ClO4-1
HClO4
perchloric acid
ClO3-1
HClO3
chloric acid
ClO2-1
HClO2
chlorous acid
ClO-1
HClO
hypochlorous acid
o Name the following ternary acids having more four oxygen possibilities

HIO ____________________
HIO3 __________________
HIO2 ____________________
HIO4 __________________
Naming Acids – Learning Check
HCl = ____________________
HF _______________________
H2SO4 ____________________
HNO3 ____________________
H3PO4 ____________________
HNO2 ____________________
Writing Formulas of Acids
 Acids are molecules that are covalently bonded, yet they have properties of ionic compounds, so use rules for
creating neutral ionic compounds.
 Formulas for acids begin with hydrogen. The oxidation state for hydrogen is +1.
 Identify if the acid is binary or ternary. If the acid is binary, it will have a “______________” prefix, all others will
be ternary.
1. Formulas of Binary Acids
 Write H+
 Identify the monotomic anion by its root name in the acid.
 Determine its charge by following the oxidation trend for the groups.
 Write the element symbol and its negative oxidation.
 Cris cross charges to create neutral acid formulas.
EX: hydrosulfuric acid = ______________________
Now Try:
hydrochloric acid = H+ + Cl- = ___________
hydrophosphoric acid = H+ +P-3= __________
hydrobromic acid = H+ + Br- = ___________
hydrofluoric acid = H+ + F- = _____________
2. Formulas of Ternary Acids

Write H+

Identify polyion by:
1. Ic  _________ and ous  __________ suffixes
2. Prefixes of per and hypo to indicate numbers of oxygen atoms for chlorates and iodates

Write formula of polyion including oxidation.
9

Criss cross charges for neutral formula.
EX:
sulfuric acid = ______________________
Now try:
phosphoric acid = (ate to ic)
nitric acid =(ate to ic)
H+ + PO4-3 = ____________
H+ + NO3- =___________
nitrous acid = (ite to ous)
sulfurous acid = (ite to ous)
H+ + NO2- = ____________
H+ + SO3-2 = ___________
perchloric acid = (ate to ic)
hypoiodous acids=
H+ + ClO4- =____________
H+ + IO-= _____________
acetic acid = (ate to ic)
H+ +C2H3O2 =___________
10
Naming Compounds Flow Chart
Does the Formula begin with H?
NO
YES
Does it begin with a metal which has more than one
oxidation number? (eg Fe, Ni, Cu, Sn, Hg)
NO
YES
It is an Acid (must be aqueous)
Does the acid contain a polyatomic ion?
YES
NO
Name the first element
followed by its
oxidation numbers
(Roman numeral)
Ending of polyatomic ion
-ate
Does the formula contain a polyatomic ion?
NO
YES
Are both elements nonmetals?
NO
YES
Name the
first
element,
then the
second
element
with the –
ide ending.
-ite
Name the polyatomic ion,
replacing the –ate ending
with -ic. Add the word acid.
Name the polyatomic ion,
replacing the –ite ending
with -ous. Add the word
acid.
Name the first element
using the proper prefix.
(never mono-). Name
the second element with
the proper prefix
(including mono- and –
ide ending.)
1 mono2 di3 tri4 tetra5 penta6 hexa7 hepta8 octa9 nano10 deca-
Write the prefix hydro, then
the name of the second
element with –ic ending.
Add the word acid.
Name the first element, then the polyatomic
ion. If two elements are present, name both,
then the polyatomic ion. (e.g. NaHCO3 is
sodium hydrogen carbonate)
11
Common Polyatomic Ions
ANIONS: 1* Acetate
2C2H3O2−
NH2−
N3−
C7H5O2−
BrO3−
ClO3−
ClO2−
OCN−
Amide
Azide
Benzoate
Bromate
* Chlorate
* Chlorite
Cyanate
* Cyanide
*
*
*
*
*
*
*
Dihydrogen phosphate
Formate
Bicarbonate
Bisulfate
Bisulfide
Hydroxide
Hypochlorite
Iodate
Nitrate
Nitrite
Perchlorate
Permanganate
Thiocyanate
Triiodide
Vanadate
CN −
H2PO4−
HCO2−
HCO3−
HSO4−
HS−
OH−
ClO−
IO3−
NO3−
NO2−
ClO4−
MnO4−
SCN−
I3−
VO3−
*
*
*
*
*
3Carbide
Carbonate
Chromate
Dichromate
Imide
Manganate
Metasilicate
Monohydrogen
phosphate
Oxalate
Peroxide
Peroxydisulfate
Phthalate
Polysulfide
Selenate
Sulfate
Sulfite
Tartrate
Tellurate
Tetraborate
Thiosulfate
Tungstate
Zincate
C2−2
CO3−2
CrO4−2
Cr2O7−2
−2
NH
MnO4−2
SiO3−2
HPO4−2
*
C2O4−2
O2−2
S2O8−2
C8H4O4−2
Sx−2
SeO4−2
SO4−2
SO3−2
C4H4O6−2
TeO4−2
B4O7−2
S2O3−2
WO4−2
ZnO2−2
4-
Aluminate
Arsenate
Borate
Citrate
Phosphate
Phosphite
Orhtosilicate
AlO3−3
AsO4−3
BO3−3
C6H5O7−3
PO4−3
PO3−3
Pyrophosphate
SiO4−4
P2O7−4
Tri-polyphosphate
P3O10−5
5-
CATIONS: 1+
* Ammonium
Hydronium
NH4+
H3 O+
The subscript is used to indicate the number of atoms for each element present. Ex. N3− The symbol indicates the type of element
present in the compound. Ex. Na= Sodium The coefficient is used to indicate the total number of molecules present. Ex.
3C8H10N4O2The superscript is used to indicate the oxidation number of each element or polyatomic ion. Ex. AlO3−3
The formula is a combination of symbols that represent the composition of a compound Ex. C4H4O6−2
Transition elements
Oxidation states for transition elements
*Silver
Ag+
Iron (II)
Fe+2
NON-METALS
Oxidation states
N-3
Nitride
Cu+
P-3
Phosphide
Copper (II)
Cu+2
O-2
Oxide
Cobalt (II)
Co+2
Cobalt (III)
Co+3
S-2
Sulfide
Tin (II)
Sn+2
F-1
Fluoride
Tin (IV)
Sn+4
Lead (II)
Pb+2
Cl-1
Chloride
Lead (IV)
Pb+4
Br-1
Bromide
Mercury (I)
Hg2 +
I-1
Iodide
Mercury (II)
Hg+2
*Zinc
Zn+2
Iron (III)
Fe+3
*Cadmium
Cd+2
Copper (I)
12
Prefix System
Prefixes for binary molecular compounds.
1
2
3
4
5
Mono
Di
Tri Tetra Penta
6
7
8
9
10
Hexa Hepta Octo Nona Deca
TERNARY ACIDS
Know all forms of ClO3-1 and IO3-1
Per--------ic
--------ic
--------ous
Hypo--------ous
Greatest # of O atoms
Greater # of O atoms
Smaller # of O atoms
Smallest # of O atoms