Writing Formulas Flow Chart

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Writing Formulas Flow Chart
no – go to
Does the name of the formula include the word “ion”?
the next page
yes – simply write the formula of the ion. Use
the periodic table to help you with the charges
(oxidation numbers) of monoatomic ions.
Cation Help
1+
NH
is ammonium ion. Transition metals and the metals to the right of the transition metals
4
on the periodic table have a roman numeral in the name to indicate the oxidation state of the
metal except for zinc, cadmium and silver. Other cations get the charge based on the number
of valence electrons they will lose to achieve a noble gas configuration.
+3
+3
+1
+1
example: iron (III) ion is Fe
aluminum ion is Al
silver ion is Ag
sodium ion is Na
Notice that all elements with “ion” in the name must have a charge in the formula.
Anion Help
1. You must memorize the 13 “standard” anions, both the number of atoms and the charge. Most
1-
1-
of these end in “ate”, the two exceptions are hydroxide ion (OH
) and cyanide ion (CN
).
2. If there is one more oxygen than the “standard” ion the prefix of “per” is added to the name.
1-
1-
Example chlorate ion is ClO
so if the ion you are considering is ClO
the name is perchlorate
3
4
ion.
3. If there is one less oxygen than the “standard” ion the “ate” ending is changed to an “ite”
1-
1
ending. Example: chlorate ion is ClO
so if the ion you are considering is ClO
the name is
3
2
chlorite ion.
4. If there are two less oxygen than the “standard” ion, a “hypo” prefix is added and the “ate”
1-
ending is also changed to an “ite” ending. Example: chlorate ion is ClO
so if the ion you are
3
1
considering is ClO
the name is hypochlorite ion.
5. If there is a hydrogen attached to the “standard” ion (also changing the charge by +1) a prefix
2-
1-
of “bi” or “hydrogen” is used to indicate this. Example: sulfate ion is SO
so HSO
is bisulfate
4
4
ion or hydrogen sulfate ion.
6. If the anion is a single element change the name to end in “ide”. Example NH
Cl the name of
4
1-
the anion is chloride ion (Cl
). The name of the compound is ammonium chloride.

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