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Chemical
Nomenclature
Chemistry - Today
•Chemical Formulas
•Memorizing 55
elements
•Rules for naming
binary compounds.
NOTES
I.
Elements
A. Symbols: come from the first
letter, or first two letters of the
element’s name.
B. Learn all 55 given elements. See
the web page.
C. Elements Test next Thursday (A)
and Friday (B)
Naming Inquiry
Formula
NaCl
KI
MgCl2
Name
Sodium Chloride
Potassium Iodide
Magnesium Chloride
What is a binary compound?
Naming Inquiry
Formula
Name
NaCl
Sodium Chloride
KI
Potassium Iodide
MgCl2
Magnesium Chloride
What does the chemical
formula of each indicate?
Naming Inquiry
Formula
Name
NaCl
Sodium Chloride
KI
Potassium Iodide
MgCl2
Magnesium chloride
Why are there two chlorines for
one magnesium?
Naming Inquiry
Formula
Name
NaCl
Sodium Chloride
KI
Potassium Iodide
MgCl2
Magnesium Chloride
What are some naming rules
that can be discovered from
these examples?
II.
Chemical Formula: represents the
composition of the compound.
A. Tells the proportion of each element
relative to each other.
1. Subscripts are used to indicate the
number of atoms of each element
in the compound.
2. The subscript follows the atom it
refers to.
II.
Formula: represents the composition of the
compound.
A. Tells the proportion of each element relative to
each other.
B. All atoms have oxidation numbers
(valence charge).
C. Polyatomic ions behave as though
they were a single atom. They have
oxidation numbers as well.
Examples: SO42- (sulfate), NO3(nitrate)
II.
Formula: represents the composition of the
compound.
A. Tells the proportion of each element relative to
each other.
B. All atoms have oxidation numbers (valence
charge).
C. Polyatomic ions behave as though they were a
single atom. They have oxidation numbers as
well.
D. The concept of valence or
charge will be used to write the
formulas.
D. The concept of valence or charge
will be used to write the
formulas.
1. Valence is either (+) or (-).
2. In all compounds the sum of all
valences is zero.
3. Metals are always (+).
4. Non-metals may be either.
5. Most polyatomic ions are (-).
D. The concept of valence or charge will be
used to write the formulas.
1. Example 1: Lithium Chloride …Li 1+ and
Cl 1-, so the formula must be LiCl.
2. Example 2: Calcium Oxide …Ca 2+ and
O 2-, so the formula must be CaO
3. Example 3: What about Lithium Oxide?
4. Answer: you need two lithium atoms for
every one oxygen to balance…Li2O
E. Atoms that have a constant valence:
(+1) = first column and Ag, (+2) = 2nd
column plus Zn and Cd, and (+3) Al.
(See columns already marked on
your periodic table.)
F. Some Atoms can have multiple
valences (charges, or oxidation
states) – see page 24 in the blue
book.
III. Naming Binary Salts & Writing their
Formulas
A. Metal plus a non-metal (two elements).
B. Metals named first, non-metal second
with an “ide” suffix.
C. Many metals have multiple valences (+
oxidation states), therefore their
particular valence must be indicated
using the stock system where a Roman
numeral indicates which valence is
used.
C. Many metals have multiple valences –
examples:
1. Example: Iron can be +2 or +3,
therefore Fe +2 is named Iron (II), and
Fe +3 is named Iron (III).
2. The Latin names ferrous (for Fe +2)
and ferric (for Fe+3) may also be used.
IV. Salts with Radicals (polyatomic
ions)
A. Four ways to identify salts
1. Metal + non-metal (binary)
2. Metal + Radical
3. Radical + Non-metal
4. Radical + Radical
IV. Salts with Radicals (polyatomic
ions)
B. Naming Salts (other than binary)
1. Name of metal + name of radical
2. Name of radical + name of nonmetal or radical
IV. Salts with Radicals (polyatomic
ions)
C. Memorization of Polyatomic Ions
(Radicals)
1.– “ite” (one less oxygen)
2. Two fewer oxygen’s then the
name starts with “hypo” and
ends with “ite”.
IV. Salts with Radicals (polyatomic ions)
C. Memorization of Polyatomic Ions
(Radicals) - continued
3. If there is one more oxygen
then use “per” as a prefix and
“ate” as a suffix.
4. Examples: NaNO3, NaNO2,
NaNO, and NaNO4
V. Naming Acids
1. Can be named as common salts
if not dissolved in water.
2. Binary Acids: hydrogen + a nonmetal.
a. Change hydrogen
hydro
b. Change -ide
-ic.
c. Followed by the word acid.
d. Example: HCl is Hydrochloric
acid
V. Naming Acids - continued
3. Ternary Acids: hydrogen + a
radical.
a. Change –ate to –ic.
b. Change –ite to –ous.
c. Also uses hypo and
per. (same as before)
d. Ex: HNO3 Nitric Acid
See pages 29-30 in the blue book for
more help on naming acids.
Assignment: More practice
naming salts and naming
acids!
Naming Compounds Test:
VI. Molecular Compounds
A. Greek System of naming
1. Only used for 2 non-metals
2. Ends in “ide”
3. Number of each kind of atom is
indicated by a Greek numerical
prefix (list on next slide)
Greek prefixes used for
molecular compounds.
Mono = 1
Hexa = 6
Di = 2
Hepta = 7
Tri = 3
Octa = 8
Tetra= 4
Nona = 9
Penta=5
Deca = 10
VI. Molecular Compounds
Non-metal + Non-metal
Formula
Name
CO2
N2O5
N2O4
_____
P4O10
Carbon Dioxide
Dinitrogen Pentoxide
_______________
Phosphorous Trichloride
_______________
A few more rules for naming binary
compounds of non-metals:
1. The prefix mono- is usually omitted
except where it is used for
emphasis, as in carbon monoxide.
2. Common usage omits the double
vowel – as in the example above
carbon monoxide is not carbon
mono-oxide.
Naming Test – Thursday
Assignments due on
Thursday 10/15:
Worksheets #1 – 9