Notes/Practice- Naming and writing formulas for Ionic Compounds
Physical Science
Notes:
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Pure substances composed of 2 or more elements that are chemically combined in a fixed
ratio/proportion are called _________________________.
Give an example of a compound. (Include the chemical formula for the compound)
________________________________________________
________________________________ is a shorthand notation that shows what elements a
compound contains and the ratio of the atoms or ions of these elements in the compound.
Describe a subscript______________________________________________________________________________
_____________________________________________________________________________.
Write the chemical formula for a compound. (Make you sure write what each letter and each
number means in the formula)
Table of Common Oxidation NumbersGroup
1
2
13 (3A) 14 (4A)
15 (5A)
16 (6A) 17 (7A) 18 (8A)
Number
Oxidation
+1
+2
+3
+4
-3
-2
-1
0
Number
The
(Ion
nonmetallic
Charge)
elements
There are exceptions:
 Hydrogen has a -1 charge when it bonds with a metal. It has a +1 charge when it
bonds with another nonmetal.
 Lead (Pb) (Found in Group 4) will normally form an ion with a +2 charge.
 Bismuth (Bi) (Found in Group 5) will normally form an ion with a +3 charge.
 Nitrogen and Phosphorus (Both found in Group 5) will also form ions with +5
charges if they bond with other nonmetals.
Writing Chemical Formulas for Ionic Compounds:
o 1) Write the symbols for the elements that are in the compound.
o 2) Find the oxidation numbers (the ion charges of the elements) and write them as
superscripts to the right of the elements.
o 3a) When the oxidation numbers (Ion Charges) are the same for both elements The ions should be combined in a 1 to 1 (1:1) ratio to balance the charges so the
compound has a neutral charge.
 Write the formula for the compound.
o 3b) When the oxidation numbers (Ion Charges) are different for the 2 elements Make a cross using the 2 elements with the oxidation numbers (step 2 above), and
this will tell you what the subscript for each element should be.
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Write the formula for the compound.
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Ex 1:
Sodium Chloride
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Naming Ionic Compounds:
Given the chemical formula for a compoundo 1) Write the name of the element with the positive ion first. Spell it normally like it is found
on the Periodic Table.
o 2) Next, write the name of the element with the negative ion. Normally, the first syllable
(1st part) of the element is used, and it will end in –ide.
Ex 1:
Ex 2:
AlCl3
LiO
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Practice:
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What is the chemical formula for Potassium Bromide?
Write the chemical formula for Calcium Chloride.
Write the chemical formula for Magnesium Fluoride.
What is the chemical formula for Potassium Nitride?
What is the chemical formula for Calcium Oxide?
What is the chemical formula for Barium Bromide?
Write the chemical formula for Lithium Fluoride.
Write the chemical formula for Aluminum Chloride.
Write the chemical formula for Sodium Fluoride.
What is the chemical formula for Barium Bromide?
What is the name for the compound Na2S?
Name the following compound: Al2O3.
Name the following compound: KI.
Name the following compound: MgCl2.
What is the name for the ionic compound Al2S3?
What is the name for the compound K2O?
Name the following compound: BaF2.
Name the following compound: Cs2O.
What is the name for the ionic compound CsCl?
What is the name for the ionic compound Ca3N2?
Ex 2:
Magnesium Nitride