4.2 Naming and Writing
Formulas for More
Complex Compounds
Period 1
Group #6
About Polyatomic Ions

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It is an ion consisting
of 2 or more atoms
bounds together
Charged enties
Have assigned special
names which must be
memorized
About Polyatomic Ions
Naming Polyatomic Ions

Except for hydroxide,
peroxide,and cyanide the
names of polyatomic ions
do not have the –ide
ending.
Naming Polyatomic Ions

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Several series of polyatomic anions
that contain an atom of a given
element –oxyanion
Ionic compounds containing
polyatomic ions are not binary
compunds, because they contain
more than 2 elements
Ex: ion: NH4+ name: ammonium
Ex: Name NH4+
Naming Polyatomic
Ions
Naming Acids

A substance that produces hydrogen ions
(H+) un hydrogen in solution; proton
donor
Rules for Naming Acids


Polyatomic aniions derived from
acids are named by droping the
–ic or –ous from acid name and
adding the –ate or –ite suffix\
Acids which do not contain
oxygen are named by adding
the hydro- preffix to the root
naem of the element folloed by
–ic suffix
Rules for Naming Acids

Example: Describe acids

Name HCIO4
Rules for Naming Acids
that do not contain Oxygen
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HF
HCI
HI
HCN
H2S
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Hydrofloric acid
Hydrochloric
acid
Hydrobromic
acid
Hydroidic acid
Hydrocyanic
acid
Hydrosulfuric
acid
Rules for Naming Acids
of Some Oxygen Containing Acids
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HNO3
HNO2
H2SO4
H2SO3
H3PO4
HC2H302
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Nitric acid
Nitrous acid
Sulfuric acid
Sulfurous acid
Phsphoric acid
Acetic acid
Writing Formulas From
Names

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Ionic compounds: usually
contain metal and nonmetal
If it is transitional metal Roman
numeral gives the charge
-ide tells you single element not
polyatomic
Ex: Nitric Acid
Writing Formulas From
Names

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Each polyatomic ions is a
complete until NEVER
break it up or change
numbers
Most end in –ate and -ite
Quiz
• 1 Name CIO• 2 Describe hot to find the name for Co 2•
3
• 3 Write the formula for tetraphosphorus
decaoxide
• 4 Name H S
•
2
• 5 Name HC2H3O2
References

www.google.com
www.yahoo.com
www.emsb.qc.ca/igurenil/science/name.html
www.foldmprep.org/gcurran/sno/sno/lessons/lesson5.4.htm
http://home.earthlink.net/ussbeaton/addinfo/formulawriting.h
tml
http://www.brandonsd.mb.ca/crocus/Staff/mckellar/sci2
0s/s2sdl/sdlchem/polyatomic.gif
http://www.corrosionsource.com/handbook/periodic/periodic
_table.gif