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Lesson 5 Ionic Compounds - Naming and Formulas

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Course: Science 10 [5 cr] - AB Ed copy 1
Book: Lesson 5 Ionic Compounds - Naming and Formulas
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Date: Sunday, 7 September 2025, 6:46 PM

Table of contents


Introduction

Please pass the salt!



B5.1 Salt shaker
Would you use this salt on your fries? I hope not! The compound in the container is actually copper(II) sulfate. The term ā€œsaltā€ is a generic term that refers to a chemical compound consisting of an assembly of cations and anions. I think you meant to say, please pass the table salt, or according to IUPAC rules, please pass the sodium chloride! In the previous lesson, you looked at why a system is needed to name compounds. In this lesson, you will learn about the IUPAC rules used to name ionic compounds.

  Targets

By the end of this lesson, you will be able to

  • write formulas for and name, using IUPAC rules, binary ionic compounds
  • write formulas for and name, using IUPAC rules, multivalent ionic compounds
  • write formulas for and name, using IUPAC rules, ionic compounds that contain polyatomic ions
  • write formulas for and name, using IUPAC rules, hydrated ionic compounds

  Watch This

Formulae of Ionic Compounds & Their Names ā€“ Part 1 @ YouTube FuseSchool ā€“ Global Education 


This is a simple introduction to the basic principles for writing formulas and naming simple binary ionic compounds. There are a few differences to keep in mind.

  1. In the modified Bohr diagrams they use, they place the electrons separate in the first energy level.

  2. At times, they place two electrons in one orbital.

  3. Compound names should not be capitalized.
 

Ionic Bonding of lithium fluoride and potassium oxide @ YouTube FuseSchool ā€“ Global Education


Need a few more examples? Here are examples for two more ionic compounds. There are a few differences to keep in mind.

  1. In the modified Bohr diagrams they use, they place the electrons separate in the first energy level.

  2. At times they place two electrons in one orbital.

  3. Compound names should not be capitalized.
 

Naming Binary Ionic Compounds

What does the prefix ā€œbiā€ mean?



B5. 2 bicycle
Bicycle, biyearly, bivalve, bifocal, binary are all words that utilize the prefix ā€œbi.ā€ Do you know what the prefix ā€œbiā€ stands for? The answer is two. In this part of the lesson, you will learn how to name binary ionic compounds, or compounds that contain two elementsā€”a metal and a non-metalā€”by following a simple set of guidelines.

1.  You can identify the compound as binary ionic because it is a metal element bonded to a non-metal element.
2.  Write the name of the metal element first.
3.  Write the name of the non-metal element second, changing the ending to ā€œide.ā€

Remember from Science 9 that compound names are not proper nouns, so do not use capital letters.

Examples

Each example has a video to go with it. To play the video, click on the play icon next to the example.
Identify the elements in the compound as being a metal bonded to a non-metal.

potassiumā€”metal
oxygenā€”non-metal
This is an ionic compound.
Write the name of the metal element.

potassium
Write the name of the non-metal element, changing the ending to ā€œide.ā€

Oxygen becomes oxide.
Combine the ion names.

potassium oxide
Watch this video to see a teacher work through this example. https://adlc.wistia.com/medias/d1xqd3gmp5
 

Identify the elements in the compound as being a metal bonded to a non-metal.

aluminiumā€”metal
chlorineā€”non-metal
This is an ionic compound.

Write the name of the metal element.

aluminium
Write the name of the non-metal element, changing the ending to ā€œide.ā€

Chlorine becomes chloride.
Combine the ion names.

aluminium chloride

Watch this video to see a teacher work through this example.  https://adlc.wistia.com/medias/0sbhpgcnjc
 


Identify the elements in the compound as being a metal bonded to a non-metal.

magnesiumā€”metal
nitrogenā€”non-metal
This is an ionic compound.

Write the name of the metal element.

magnesium
Write the name of the non-metal element, changing the ending to ā€œide.ā€

Nitrogen becomes nitride.
Combine the ion names.

magnesium nitride

Watch this video to see a teacher work through this example.  https://adlc.wistia.com/medias/n2zvqb5s1s
 


Identify the elements in the compound as being a metal bonded to a non-metal.

bariumā€”metal
sulfurā€”non-metal
This is an ionic compound.

Write the name of the metal element.


Write the name of the non-metal element, changing the ending to ā€œide.ā€

Sulfur becomes sulfide.
Combine the ion names.

barium sulfide

Watch this video to see a teacher work through this example.  https://adlc.wistia.com/medias/0im0hviti9
 



  Read This

Please read page 42 in your Science 10 textbook. Make sure you take notes on your readings to study from later. You should focus on naming binary ionic compounds. Remember, if you have any questions or you do not understand something, ask your teacher!

  Practice Questions

Complete the following practice questions to check your understanding of the concept you just learned. Make sure you write complete answers to the practice questions in your notes. After you have checked your answers, make corrections to your responses (where necessary) to study from.

  1. Provide the correct IUPAC name for each of the following compounds.

    ZnS
    Li3P
    NaF
    MgI2
    CaBr2
    K3N
    Al2O3

    ZnS
    		 zinc sulfide
    Li3P lithium phosphide
    NaF sodium flouride
    MgI2 magnesium iodide
    CaBr2 calcium bromide
    K3N potassium nitride
    Al2O3 aluminium oxide

Formulas of Binary Ionic Compounds

Did you know that sapphires, emeralds, and rubies are all crystal lattice structures of the same binary ionic compound?



B5.3 Three rings: one with a sapphire, one with an emerald, and one with a ruby
Sapphires, emeralds, and rubies are composed of aluminium oxide. The characteristic colours come from trace amounts of transition metals imbedded in the structures.

The formula of aluminum oxide is Al2O3, which seems to imply that the structure is a simple molecule of two Al atoms and three O atoms. How can large gem stones be created from this? In reality, the formula shows the ratio of cations to anions that exist in the giant crystal lattice structure.

Subscripts indicate the ratio of cations to anions needed to create a neutral compound.



The guidelines for writing formulas for binary ionic compounds are as follows:

  1. Identify the type of compoundā€”a metal element with a non-metal element is ionic.
  2. Write the ion symbols.
  3. Determine the number of the ions of each element that will result in a neutral compound. Do this by determining the lowest common multiple.
  4. Determine the factor (number) that each ion needs to be multiplied by to create the lowest common multiple.
  5. Write these as subscripts. Do not write the subscript 1.


Examples


Each example has a video to go with it. To play the video, click on the play icon next to the example.

Identify the type of compound.

magnesiumā€”metal
chlorideā€”non-metal
This is an ionic compound.
Write the ion symbols.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msupĀ»Ā«miĀ»MgĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msupĀ»Ā«miĀ»ClĀ«/miĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/msupĀ»Ā«/mathĀ»
Determine the lowest common multiple of the two charges.

The lowest common multiple between 2 and 1 is 2.
Determine the factor to multiple each ion by.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«mtable columnspacing=ĀØ0pxĀØ columnalign=ĀØright center leftĀØĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msupĀ»Ā«miĀ»MgĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»1Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msupĀ»Ā«miĀ»ClĀ«/miĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«/mtableĀ»Ā«/mathĀ»
This will create a neutral compound.
The ratio of Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msupĀ»Ā«miĀ»MgĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«/mathĀ» to Clā€“ is 1:2.
Write the formula with subscripts.

Short cut: There is a short cut that is known as swap and drop (or criss-cross the charges) to help you determine the subscripts. If you use this method, you need to remember to reduce the subscripts to lowest terms.

1.  Write the formulas of the ions.
 Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msupĀ»Ā«miĀ»MgĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msupĀ»Ā«miĀ»ClĀ«/miĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/msupĀ»Ā«/mathĀ»
2.  Swap and drop the charges (just the numbers, not the signs).
3.  Reduce subscripts to lowest terms. (cannot be reduced)
4.  Write the formula.
 MgCl2

Watch this video to see a teacher work through this example. https://adlc.wistia.com/medias/aj2i67vem6
 

Identify the type of compound.

zincā€”metal
nitrideā€”non-metal
This is an ionic compound.
Write the ion symbols.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msupĀ»Ā«miĀ»ZnĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msupĀ»Ā«mi mathvariant=ĀØnormalĀØĀ»NĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«/mathĀ»

Determine the lowest common multiple of the two charges.

The lowest common multiple between 2 and 3 is 6.
Determine the factor to multiple each ion by.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«mtable columnspacing=ĀØ0pxĀØ columnalign=ĀØright center leftĀØĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msupĀ»Ā«miĀ»ZnĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»6Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msupĀ»Ā«mi mathvariant=ĀØnormalĀØĀ»NĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»6Ā«/mnĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«/mtableĀ»Ā«/mathĀ»
This will create a neutral compound.
The ratio of Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msupĀ»Ā«miĀ»ZnĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«miĀ»toĀ«/miĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msupĀ»Ā«mi mathvariant=ĀØnormalĀØĀ»NĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«/mathĀ» is 3:2.
Write the formula with subscripts.


Watch this video to see a teacher work through this example. https://adlc.wistia.com/medias/oy12333a3k
 


Identify the type of compound.

calciumā€”metal
oxideā€”non-metal
This is an ionic compound.
Write the ion symbols.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msupĀ»Ā«miĀ»CaĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msupĀ»Ā«mi mathvariant=ĀØnormalĀØĀ»OĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«/mathĀ»


This can be reduced to CaO.


 
Determine the lowest common multiple of the two charges.

The lowest common multiple between 2 and 2 is 2.
Determine the factor to multiple each ion by.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«mtable columnspacing=ĀØ0pxĀØ columnalign=ĀØright center leftĀØĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msupĀ»Ā«miĀ»CaĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»1Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msupĀ»Ā«mi mathvariant=ĀØnormalĀØĀ»OĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»1Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«/mtableĀ»Ā«/mathĀ»
This will create a neutral compound.
The ratio of Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msupĀ»Ā«miĀ»CaĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«miĀ»toĀ«/miĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msupĀ»Ā«mi mathvariant=ĀØnormalĀØĀ»OĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«/mathĀ» is 1:1.
Write the formula with subscripts.


Watch this video to see a teacher work through this example. https://adlc.wistia.com/medias/kfqs0m6914
 


Identify the type of compound.

aluminiumā€”metal
fluorideā€”non-metal
This is an ionic compound.
Write the ion symbols.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msupĀ»Ā«miĀ»AlĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msupĀ»Ā«mi mathvariant=ĀØnormalĀØĀ»FĀ«/miĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/msupĀ»Ā«/mathĀ»

Determine the lowest common multiple of the two charges.

The lowest common multiple between 3 and 1 is 3.
Determine the factor to multiple each ion by.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«mtable columnspacing=ĀØ0pxĀØ columnalign=ĀØright center leftĀØĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msupĀ»Ā«miĀ»AlĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»1Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msupĀ»Ā«mi mathvariant=ĀØnormalĀØĀ»FĀ«/miĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«/mtableĀ»Ā«/mathĀ»
This will create a neutral compound.
The ratio of Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msupĀ»Ā«miĀ»AlĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«/mathĀ» to Fā€“ is 1:3.
Write the formula with subscripts.


Watch this video to see a teacher work through this example. https://adlc.wistia.com/medias/sn7r92mttf
 



  Interactive Activity

Creating Compounds Manipulative

To help you visualize how ions combine in certain ratios to make ionic compounds, work through the following examples. You can use this manipulative to help you write formulas for ionic compounds in the practice question section and on your assignment.

For cations, each extension represents an electron that needs to be lost. For anions, each divot represents an electron that needs to be gained. The goal is to combine the correct ratio of cations to anions to create neutral compounds.

Click on the procedure 1 tab to continue.

  1. Click on the play icon to make a copy of the creating compound manipulative. Print students can access the document in the Online Resources for Print Students section of their online course.
  2. Predict the formula for magnesium chloride by dragging a magnesium ion to the work surface.

    How many bonds will magnesium form?

  3. Drag a chloride ion onto the work surface.

    How many bonds will chloride form?

  4. Drag enough chloride ions to create a stable compound.

    How many magnesium ions are needed? Chloride ions?

    magnesium ions = 1
    chloride ions = 2
  5. Clear the work surface by returning all cations and anions.
  6. Click on the procedure 2 tab to continue.
  1. Predict the formula for zinc nitride by dragging a zinc ion to the work surface.

    How many bonds will zinc form?

  2. Drag a nitride ion to the work surface.

    How many bonds will nitride form?

  3. Drag enough zinc ions and nitride ions to create a stable compound.

    How many zinc ions are needed? Nitride ions?

    zinc ions = 3
    Nitride ions = 2
  4. Clear the work surface by returning all cations and anions.
  5. Click on the procedure 3 tab to continue.
  1. Predict the formula for calcium oxide by dragging a calcium ion to the work surface.

    How many bonds will calcium form?

  2. Drag an oxide ion onto the work surface.

    How many bonds will oxide form?

  3. Drag enough oxide ions to create a stable compound.

    How many calcium ions are needed? Oxide ions?

    calcium ions = 1
    oxide ions = 1
  4. Clear the work surface by returning all cations and anions.
  5. Click on the procedure 4 tab to continue.
  1. Predict the formula for aluminium fluoride by dragging an aluminium ion to the work surface.

    How many bonds will aluminium form?

  2. Drag a fluoride ion onto the work surface.

    How many bonds will fluoride form?

  3. Drag enough fluoride ions to create a stable compound.

    How many aluminum ions are needed? Fluoride ions?

    aluminum ions = 1
    fluoride ions = 3
  4. Clear the work surface by returning all cations and anions.

  Digging Deeper

Ā© Wikimedia Commons
B5.4 Star sapphire

The Star of Adam is the largest star sapphire in the world. It weighs 1 404 carats (281 g) and has been valued at over $300 million. It was discovered in Sri Lanka, which is a well-known location for gem mining.

  Read This

Please read pages 42 to 43 in your Science 10 textbook. Make sure you take notes on your readings to study from later. You should focus on how to write formulas for binary ionic compounds. Remember, if you have any questions or you do not understand something, ask your teacher!

  Practice Questions

Complete the following practice questions to check your understanding of the concept you just learned. Make sure you write complete answers to the practice questions in your notes. After you have checked your answers, make corrections to your responses (where necessary) to study from.

  1. Provide the correct IUPAC name for each of the following compounds.

    zinc bromide
    potassium nitride
    lithium iodide
    barium phosphide
    aluminium sulfide
    magnesium oxide
    sodium arsenide

    zinc bromide
    		 ZnBr2
    potassium nitride
    		 K3N
    lithium iodide
    		 LiI
    barium phosphide
    		 Ba3P2
    aluminium sulfide Al2S3
    magnesium oxide
    		 MgO
    sodium arsenide
    		 Na3As

  Naming Compounds That Contain Polyatomic Ions

Did you know that many common household substances, such as baking soda, are ionic compounds?

B5.5 Baking soda
Baking soda is a more complex ionic compound than the binary ionic compounds you just learned about. The IUPAC name of baking soda is sodium hydrogen carbonate and the chemical formula is NaHCO3. Ionic compounds that contain more than two elements will contain a polyatomic ion. A polyatomic ion is a group of elements that act as unit and have a charge. The majority of these ions are anions; however, there is one cation polyatomic that you will be working with in this course: ammonium, Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msupĀ»Ā«miĀ»NHĀ«/miĀ»Ā«mrowĀ»Ā«mnĀ»4Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/mrowĀ»Ā«/msupĀ»Ā«/mathĀ». In your Science 10 data booklet, there is a table that identifies the common polyatomic ions. Compounds that contain polyatomic ions are classified as ionic compounds and, as such, have similar rules for naming and writing formulas.

  Watch This

Formulae of Ionic Compounds and Their Names: Part 2 @ YouTube FuseSchool ā€“ Global Education 


This video goes over some examples of writing formulas and naming compounds that contain polyatomic ions. Please note that in this video they use capital letters when writing names of compounds; this is not proper format. The last 40 s of this video goes on to give examples of multivalent ions. You will learn about multivalent ions later in the lesson.

Hint: If the compound contains a metal, it is an ionic compound.



 


  Digging Deeper

Bleach has the IUPAC name of sodium hypochlorite and the formula NaClO. Many polyatomic ions contain oxygen. There is a pattern that relates the number of oxygen atoms to the polyatomic name. If the polyatomic ion ends with ā€œā€“ate,ā€ that is the ā€œbaseā€ oxyanion name in the series. If there is a ā€œperā€“ ā€œ prefix added, there is one more oxygen in the ā€œbaseā€ oxyanion formula. If the suffix changes to ā€œā€“ite,ā€ there is one less oxygen atom in the formula. And if there is a ā€œhypoā€“ā€ prefix, there is even one fewer oxygen.
B5.6 Bleach

  Did You Know?

B5.7 Soap making

Strong bases, such as lye, which is used to make soap, are ionic compounds of hydroxide. This makes base formulas easy to recognize!

sodium hydroxideā€”NaOH
potassium hydroxideā€”KOH
lithium hydroxideā€”LiOH

  Naming Compounds That Contain Polyatomic Ions Cont'd


Regardless of the number of elements in the compound formula, the name will consist of two parts: the cation name and the anion name. If you find yourself stringing several element names together to name a compound name, chances are the compound contains a polyatomic and you need to look for the polyatomic name in the table.

Examples


Each example has a video to go with it. To play the video, click on the play icon next to the example.
Identify the composition of the compound.

K+ā€”metal
Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msupĀ»Ā«msubĀ»Ā«miĀ»SOĀ«/miĀ»Ā«mnĀ»4Ā«/mnĀ»Ā«/msubĀ»Ā«mrowĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»-Ā«/moĀ»Ā«/mrowĀ»Ā«/msupĀ»Ā«/mathĀ»ā€”polyatomic
This is an ionic compound.
Write the name of the cation.

potassium
Write the name of the anion (if it is a polyatomic, do not change the ending; if it is a non-metallic element, change the ending to ā€œideā€).

Combine the ion names.

potassium sulfate

Watch this video to see a teacher work through this example.  https://adlc.wistia.com/medias/z5h9i9btsv
 

Identify the composition of the compound.

Li+ā€”metal
Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msubsupĀ»Ā«miĀ»NOĀ«/miĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»-Ā«/moĀ»Ā«/msubsupĀ»Ā«/mathĀ»ā€”polyatomic
This is an ionic compound.
Write the name of the cation.

Write the name of the anion (if it is a polyatomic, do not change the ending; if it is a non-metallic element, change the ending to ā€œideā€).

Combine the ion names.

lithium nitrite

Watch this video to see a teacher work through this example.  https://adlc.wistia.com/medias/hw837oanwo
 


Identify the composition of the compound.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msubsupĀ»Ā«miĀ»NHĀ«/miĀ»Ā«mnĀ»4Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msubsupĀ»Ā«/mathĀ»ā€”polyatomic
Clā€“ā€”non-metal
This is an ionic compound.
Write the name of the cation.

ammonium
Write the name of the anion (if it is a polyatomic, do not change the ending; if it is a non-metallic element, change the ending to ā€œideā€).

Since Cl is chlorine, a non-metal, the element name changes to end in ā€œide.ā€
Combine the ion names.

ammonium chloride

Watch this video to see a teacher work through this example.  https://adlc.wistia.com/medias/jn0n07wj75
 


Identify the composition of the compound.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msupĀ»Ā«miĀ»CaĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«/mathĀ»ā€”metal
H2PO4ā€“ā€”polyatomic
This is an ionic compound.
Write the name of the cation.

Write the name of the anion (if it is a polyatomic, do not change the ending; if it is a non-metallic element, change the ending to ā€œideā€).

dihydrogen phosphate
Combine the ion names.

calcium dihydrogen phosphate

Watch this video to see a teacher work through this example.  https://adlc.wistia.com/medias/a8ht0ysqk5
 



  Read This

Please read pages 44 to 46 in your Science 10 textbook. Make sure you take notes on your readings to study from later. You should focus on the rules for naming ionic compounds that contain polyatomic ions. Remember, if you have any questions or you do not understand something, ask your teacher!

  Practice Questions

Complete the following practice questions to check your understanding of the concept you just learned. Make sure you write complete answers to the practice questions in your notes. After you have checked your answers, make corrections to your responses (where necessary) to study from.

  1. Provide the correct IUPAC name for each of the following compounds.

    ZnCO3
    Li3PO4
    Ba(OH)2
    MgSO3
    NH4Br
    KMnO4
    NaHSO4

    ZnCO3
    		 zinc carbonate
    Li3PO4 lithium phosphate
    Ba(OH)2 barium hydroxide
    MgSO3 magnesium sulfite
    NH4Br ammonium bromide
    KMnO4 potassium permanganate
    NaHSO4 sodium hydrogen sulfate

  Formulas of Compounds That Contain Polyatomic Ions

Did you know that the pyramids of Giza are made from limestone?

B5.8 The Great Sphinx and the pyramids of Giza
Limestone is the common name for calcium carbonate, CaCO3. Just as you learned how to write chemical formulas for binary ionic compounds, you will now learn how to write formulas for ionic compounds that contain polyatomic ions.

Because these are ionic compounds, there still needs to be a balancing of charges to create a neutral substance. One of the key points to remember when writing formulas for ionic compounds that contain polyatomic ions is to use brackets around the polyatomic ion when there is the need of a subscript.

Hint: If the compound name ends with ā€œateā€ or ā€œite,ā€ then it contains a polyatomic. There are also some polyatomic ions that end in ā€œide.ā€


Examples


Each example has a video to go with it. To play the video, click on the play icon next to the example.

Identify the type of compound.

sodiumā€”metal
chloriteā€”polyatomic
This is an ionic compound.
Write the ion symbols.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msupĀ»Ā«miĀ»NaĀ«/miĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msubsupĀ»Ā«miĀ»ClOĀ«/miĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»-Ā«/moĀ»Ā«/msubsupĀ»Ā«/mathĀ»



Determine the lowest common multiple of the two charges.

The lowest common multiple between 1 and 1 is 1.
Determine the factor to multiple each ion by.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«mtable columnspacing=ĀØ0pxĀØ columnalign=ĀØright center leftĀØĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msupĀ»Ā«miĀ»NaĀ«/miĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»1Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»1Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msubsupĀ»Ā«miĀ»ClOĀ«/miĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»-Ā«/moĀ»Ā«/msubsupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»1Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»1Ā«/mnĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«/mtableĀ»Ā«/mathĀ»
This will create a neutral compound.
The ratio of Na+ to Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msubsupĀ»Ā«miĀ»ClOĀ«/miĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»-Ā«/moĀ»Ā«/msubsupĀ»Ā«/mathĀ» is 1:1.
Write the formula with subscripts.


Watch this video to see a teacher work through this example. https://adlc.wistia.com/medias/sodiarn5sj ;
 

Identify the type of compound.

magnesiumā€”metal
hydroxideā€”polyatomic
This is an ionic compound.
Write the ion symbols.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msupĀ»Ā«miĀ»MgĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msupĀ»Ā«miĀ»OHĀ«/miĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/msupĀ»Ā«/mathĀ»



Determine the lowest common multiple of the two charges.

The lowest common multiple between 2 and 1 is 2.
Determine the factor to multiple each ion by.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«mtable columnspacing=ĀØ0pxĀØ columnalign=ĀØright center leftĀØĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msupĀ»Ā«miĀ»MgĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»1Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msupĀ»Ā«miĀ»OHĀ«/miĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«/mtableĀ»Ā«/mathĀ»
This will create a neutral compound.
The ratio of Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msupĀ»Ā«miĀ»MgĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«/mathĀ» to OHā€“ is 1:2.
Write the formula with subscripts.


Watch this video to see a teacher work through this example.  https://adlc.wistia.com/medias/7atovzgclg
 


Identify the composition of the compound.

ammoniumā€”polyatomic
fluorideā€”non-metal
This is an ionic compound.
Write the ion symbols.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msubsupĀ»Ā«miĀ»NHĀ«/miĀ»Ā«mnĀ»4Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msubsupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msupĀ»Ā«mi mathvariant=ĀØnormalĀØĀ»FĀ«/miĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/msupĀ»Ā«/mathĀ»




Determine the lowest common multiple of the two charges.

The lowest common multiple between 1 and 1 is 1.
Determine the factor to multiple each ion by.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«mtable columnspacing=ĀØ0pxĀØ columnalign=ĀØright center leftĀØĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msubsupĀ»Ā«miĀ»NHĀ«/miĀ»Ā«mnĀ»4Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msubsupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»1Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»1Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msupĀ»Ā«mi mathvariant=ĀØnormalĀØĀ»FĀ«/miĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»1Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»1Ā«/mnĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«/mtableĀ»Ā«/mathĀ»
This will create a neutral compound.
The ratio of Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msubsupĀ»Ā«miĀ»NHĀ«/miĀ»Ā«mnĀ»4Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msubsupĀ»Ā«/mathĀ» to Fā€“ is 1:1.
Write the formula with subscripts.


Watch this video to see a teacher work through this example. https://adlc.wistia.com/medias/xkw64p8llr
 


Identify the type of compound.

aluminiumā€”metal
sulfateā€”polyatomic
This is an ionic compound.
Write the ion symbols.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msupĀ»Ā«miĀ»AlĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msubsupĀ»Ā«miĀ»SOĀ«/miĀ»Ā«mnĀ»4Ā«/mnĀ»Ā«mrowĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»-Ā«/moĀ»Ā«/mrowĀ»Ā«/msubsupĀ»Ā«/mathĀ»

Determine the lowest common multiple of the two charges.

The lowest common multiple between 3 and 2 is 6.
Determine the factor to multiple each ion by.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«mtable columnspacing=ĀØ0pxĀØ columnalign=ĀØright center leftĀØĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msupĀ»Ā«miĀ»AlĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»6Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msubsupĀ»Ā«miĀ»SOĀ«/miĀ»Ā«mnĀ»4Ā«/mnĀ»Ā«mrowĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»-Ā«/moĀ»Ā«/mrowĀ»Ā«/msubsupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»6Ā«/mnĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«/mtableĀ»Ā«/mathĀ»
This will create a neutral compound.
The ratio of Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msupĀ»Ā«miĀ»AlĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«/mathĀ» to Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msubsupĀ»Ā«miĀ»SOĀ«/miĀ»Ā«mnĀ»4Ā«/mnĀ»Ā«mrowĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»-Ā«/moĀ»Ā«/mrowĀ»Ā«/msubsupĀ»Ā«/mathĀ» is 2:3.
Write the formula with subscripts.

Al2(SO4)3

Watch this video to see a teacher work through this example.  https://adlc.wistia.com/medias/00g9pxgtli
 


Identify the type of compound.

lithiumā€”metal
hydrogen phosphateā€”polyatomic
This is an ionic compound.
Write the ion symbols.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msupĀ»Ā«miĀ»LiĀ«/miĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msubsupĀ»Ā«miĀ»HPOĀ«/miĀ»Ā«mnĀ»4Ā«/mnĀ»Ā«mrowĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»-Ā«/moĀ»Ā«/mrowĀ»Ā«/msubsupĀ»Ā«/mathĀ»


Determine the lowest common multiple of the two charges.

The lowest common multiple between 2 and 1 is 2.
Determine the factor to multiple each ion by.

Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«mtable columnspacing=ĀØ0pxĀØ columnalign=ĀØright center leftĀØĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msupĀ»Ā«miĀ»LiĀ«/miĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msubsupĀ»Ā«miĀ»HPOĀ«/miĀ»Ā«mnĀ»4Ā«/mnĀ»Ā«mrowĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»-Ā«/moĀ»Ā«/mrowĀ»Ā«/msubsupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»1Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«/mtableĀ»Ā«/mathĀ»
This will create a neutral compound.
The ratio of Li+ to Ā«math xmlns=ĀØhttp://www.w3.org/1998/Math/MathMLĀØĀ»Ā«msubsupĀ»Ā«miĀ»HPOĀ«/miĀ»Ā«mnĀ»4Ā«/mnĀ»Ā«mrowĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»-Ā«/moĀ»Ā«/mrowĀ»Ā«/msubsupĀ»Ā«/mathĀ» is 2:1.
Write the formula with subscripts.


Watch this video to see a teacher work through this example.  https://adlc.wistia.com/medias/h941wfwzfh
 


  Read This

Please read pages 44 to 46 in your Science 10 textbook. Make sure you take notes on your readings to study from later. You should focus on the rules for writing formulas for ionic compounds that contain polyatomic ions. Remember, if you have any questions or you do not understand something, ask your teacher!

  Practice Questions

Complete the following practice questions to check your understanding of the concept you just learned. Make sure you write complete answers to the practice questions in your notes. After you have checked your answers, make corrections to your responses (where necessary) to study from.

  1. Provide the correct IUPAC name for each of the following compounds.

    zinc sulfate
    potassium dichromate
    ammonium iodide
    barium phosphate
    aluminium sulfite
    magnesium cyanide
    sodium hydrogen sulfide

    zinc sulfate
    		 ZnSO4
    potassium dichromate
    		 K2Cr2O7
    ammonium iodide NH4I
    barium phosphate BA3(PO4)2
    aluminium sulfite Al2(SO3)3
    magnesium cyanide Mg(CN)2
    sodium hydrogen sulfide NaHS

  Writing Formulas for Compounds that contain Multivalent Ions

How do we deal with particular metals that have multiple ion charges?


Ā© Wikimedia Commons
B5.9 Chromium(VI) oxide
The movie Erin Brockovich is based on a real court case in which a company caused hexavalent chromium to leach into water supplies, resulting in devastating health effects of the residents of Hinkley, California. Hexavalent chromium is toxic, corrosive, and carcinogenic. But what does hexavalent mean?

Some metals can form ions with various ion charges; for example, chromium can have ion charges of Ā«mathĀ»Ā«msupĀ»Ā«miĀ»CrĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»6Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»,Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msupĀ»Ā«miĀ»CrĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»,Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«miĀ»andĀ«/miĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msupĀ»Ā«miĀ»CrĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«/mathĀ» and more rarely Ā«mathĀ»Ā«msupĀ»Ā«miĀ»CrĀ«/miĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«moĀ»,Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msupĀ»Ā«miĀ»CrĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»4Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»,Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«miĀ»andĀ«/miĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msupĀ»Ā«miĀ»CrĀ«/miĀ»Ā«msupĀ»Ā«mrowĀ»Ā«/mrowĀ»Ā«mrowĀ»Ā«mnĀ»5Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/mrowĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«/mathĀ». Unlike hexavalent chromium, most other chromium ion compounds are not dangerous. The compound name that contains a multivalent metal must clearly identify which valiancy is in the compound. This is achieved by the use of Roman numerals.

If no indication is given (i.e., no Roman numerals), then assume the most common ion charge is present, which is the one written first on the periodic table.


The steps for writing formulas for multivalent ionic compounds are essentially the same as they are for binary ionic compounds.  The one difference is that you can determine the cation charge without checking the periodic table.  The given Roman numeral following the metal ion is equal to the magnitude of the positive charge on the ion.  
Ā© Wikimedia Commons
B5.10 Chromium(III) oxide

Examples


Each example has a video to go with it. To play the video, click on the play icon next to the example.

Identify the type of compound.

chromiumā€”metal
fluorideā€”non-metal
This is an ionic compound.
Write the ion symbols.

Ā«mathĀ»Ā«msupĀ»Ā«miĀ»CrĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msupĀ»Ā«mi mathvariant=ĀØnormalĀØĀ»FĀ«/miĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/msupĀ»Ā«/mathĀ»


Determine the lowest common multiple of the two charges.

The lowest common multiple between 3 and 1 is 3.
Determine the factor to multiple each ion by.

Ā«mathĀ»Ā«mtable columnspacing=ĀØ0pxĀØ columnalign=ĀØright center leftĀØĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msupĀ»Ā«miĀ»CrĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»1Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msupĀ»Ā«mi mathvariant=ĀØnormalĀØĀ»FĀ«/miĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«/mtableĀ»Ā«/mathĀ»
This will create a neutral compound.
The ratio of Ā«mathĀ»Ā«msupĀ»Ā«miĀ»CrĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«/mathĀ» to Fā€“ is 1:3.
Write the formula with subscripts.


Watch this video to see a teacher work through this example. https://adlc.wistia.com/medias/0cj3jt7ano
 

Identify the type of compound.

copperā€”metal
sulfateā€”polyatomic
This is an ionic compound.
Write the ion symbols.

Ā«mathĀ»Ā«msupĀ»Ā«miĀ»CuĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msubsupĀ»Ā«miĀ»SOĀ«/miĀ»Ā«mnĀ»4Ā«/mnĀ»Ā«mrowĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»-Ā«/moĀ»Ā«/mrowĀ»Ā«/msubsupĀ»Ā«/mathĀ»


These subscripts can be reduced to CuSO4.


Determine the lowest common multiple of the two charges.

The lowest common multiple between 2 and 2 is 2.
Determine the factor to multiple each ion by.

Ā«mathĀ»Ā«mtable columnspacing=ĀØ0pxĀØ columnalign=ĀØright center leftĀØĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msupĀ»Ā«miĀ»CuĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»1Ā«/mnĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«mtrĀ»Ā«mtdĀ»Ā«msubsupĀ»Ā«miĀ»SOĀ«/miĀ»Ā«mnĀ»4Ā«/mnĀ»Ā«mrowĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»-Ā«/moĀ»Ā«/mrowĀ»Ā«/msubsupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«moĀ»Ā§#215;Ā«/moĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»1Ā«/mnĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»=Ā«/moĀ»Ā«/mtdĀ»Ā«mtdĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»Ā§#8211;Ā«/moĀ»Ā«/mtdĀ»Ā«/mtrĀ»Ā«/mtableĀ»Ā«/mathĀ»
This will create a neutral compound.
The ratio of Ā«mathĀ»Ā«msupĀ»Ā«miĀ»CuĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«miĀ»toĀ«/miĀ»Ā«moĀ»Ā§#160;Ā«/moĀ»Ā«msubsupĀ»Ā«miĀ»SOĀ«/miĀ»Ā«mnĀ»4Ā«/mnĀ»Ā«mrowĀ»Ā«mnĀ»2Ā«/mnĀ»Ā«moĀ»-Ā«/moĀ»Ā«/mrowĀ»Ā«/msubsupĀ»Ā«/mathĀ» is 1:1.
Write the formula with subscripts.


Watch this video to see a teacher work through this example.  https://adlc.wistia.com/medias/vize8c3fee
 



  Read This

Please read page 44 in your Science 10 textbook. Make sure you take notes on your readings to study from later. You should focus on determining the cationā€™s charge from the Roman numerals. Remember, if you have any questions or you do not understand something, ask your teacher!

  Practice Questions

Complete the following practice questions to check your understanding of the concept you just learned. Make sure you write complete answers to the practice questions in your notes. After you have checked your answers, make corrections to your responses (where necessary) to study from.

  1. Provide the correct IUPAC name for each of the following compounds.

    iron(III) sulfate
    gold(I) sulfide
    nickel(II) nitrite
    manganese(IV) oxide

    iron(III) sulfate
    		 Fe2(SO4)3
    gold(I) sulfide
    		 Au2S
    nickel(II) nitrite Ni(NO2)2
    manganese(IV) oxide MnO2

  Naming Ionic Compounds that Contain Multivalent Ions

Can you believe that these two containers both hold copper chloride?


Ā© Wikimedia Commons
B5.11 White solid in a liquid
When naming ionic compounds that contain multivalent ions, the valency (charge) of the transition metal must be identified as a Roman numeral written directly after the metal name. The vial in image B5.11 contains copper(I) chloride, a white solid with low solubility in water; and the vial in image B5.12 contains a solution of copper(II) chloride, which is highly soluble in water.

Eighty percent of the time if you uncross the subscripts (from the swap and drop), the correct charge on the multivalent ion is indicated. The exception would be when charges were reduced; so remember to also check the charge on the anion.

It should be noted that according to IUPAC nomenclature standards, no space is placed between the name of the multivalent cation and the bracketed Roman numeral.  For example, it is incorrect to name CuCl as copper (I) chloride.  Rather, it should be named copper(I) chloride.  Please notice this important detail as you work through the following examples to solidify your understanding of multivalent ionic nomenclature.

B5.12 Blue liquid in a vial

Examples


Each example has a video to go with it. To play the video, click on the play icon next to the example.

Identify the composition of the compound.

Coā€”multivalent metal
Clā€”non-metal
This is an ionic compound that needs Roman numerals.
Write the name of the cation.

cobalt

Cobalt is multivalent, so it will either be cobalt(II) or cobalt(III).

ā€œUncrossā€ the subscripts to determine the charge on cobalt.



As a double check, look on the periodic table: Is the charge on chloride 1ā€“? Yes! This means that the formula has not been reduced and this method is valid.
Write the name of the anion (if it is a polyatomic, do not change the ending; if it is a non-metallic element, change the ending to ā€œideā€).

Cl is the non-metal chlorine, so the end changes to ā€œide.ā€

chloride
Combine the ion names, including the Roman numeral representing the charge on the cation.

cobalt(II) chloride

Watch this video to see a teacher work through this example.  https://adlc.wistia.com/medias/2px35op6kq
 


Identify the composition of the compound.

Feā€”multivalent metal
Sā€”non-metal
This is an ionic compound that needs Roman numerals.
Write the name of the cation.

iron

Iron is multivalent, so it will either be iron(II) or iron(III).

ā€œUncrossā€ the subscripts to determine the charge on iron.



As a double check, look on the periodic table: Is the charge on sulfide 2-? Yes! This means that the formula has not been reduced and this method is valid.
Write the name of the anion (if it is a polyatomic, do not change the ending; if it is a non-metallic element, change the ending to ā€œideā€).

S is the non-metal sulfur, so the end changes to ā€œide.ā€

sulfide
Combine the ion names, including the Roman numeral representing the charge on the cation.

iron(III) sulfide

Watch this video to see a teacher work through this example.  https://adlc.wistia.com/medias/c0odxvlpcc
 


Identify the composition of the compound.

Snā€”multivalent metal
Oā€”non-metal
This is an ionic compound that needs Roman numerals.
Write the name of the cation.

tin

Tin is multivalent, so it will either be tin(II) or tin(IV).

 ā€œUncrossā€ the subscripts to determine the charge on tin.



As a double check, look on the periodic table: Is the charge on oxide 1ā€“? No! This means that the formula has been reduced, the charge on oxide is 2ā€“, so this compound has been reduced by a factor of 2; therefore the charge on Sn needs to be doubledā€”Ā«mathĀ»Ā«msupĀ»Ā«miĀ»SnĀ«/miĀ»Ā«msupĀ»Ā«mnĀ»4Ā«/mnĀ»Ā«moĀ»+Ā«/moĀ»Ā«/msupĀ»Ā«/msupĀ»Ā«/mathĀ».
Write the name of the anion (if it is a polyatomic, do not change the ending; if it is a non-metallic element, change the ending to ā€œideā€).

O is the non-metal oxygen, so the end changes to ā€œide.ā€

oxide
Combine the ion names, including the Roman numeral representing the charge on the cation.

tin(IV) oxide

Watch this video to see a teacher work through this example.  https://adlc.wistia.com/medias/xp3pxkknks
 

Identify the composition of the compound.

Crā€”multivalent metal
Ā«mathĀ»Ā«msubsupĀ»Ā«miĀ»NOĀ«/miĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»-Ā«/moĀ»Ā«/msubsupĀ»Ā«/mathĀ»ā€”polyatomic
This is an ionic compound that needs Roman numerals.
Write the name of the cation.

chromium

Chromium is multivalent, so it will either be chromium(II) or chromium(III).

ā€œUncrossā€ the subscripts to determine the charge on tin.



As a double check, look on the table of polyatomics: Is the charge on NO3 1ā€“? Yes! This means that the formula has not been reduced and this method is valid.
Write the name of the anion (if it is a polyatomic, do not change the ending; if it is a non-metallic element, change the ending to ā€œideā€).

Ā«mathĀ»Ā«msubsupĀ»Ā«miĀ»NOĀ«/miĀ»Ā«mnĀ»3Ā«/mnĀ»Ā«moĀ»-Ā«/moĀ»Ā«/msubsupĀ»Ā«/mathĀ» is a polyatomic.

nitrate
Combine the ion names, including the Roman numeral representing the charge on the cation.

chromium(III) nitrate

Watch this video to see a teacher work through this example. https://adlc.wistia.com/medias/zqjej3g4eu
 


  Read This

Please read page 44 in your Science 10 textbook. Make sure you take notes on your readings to study from later. You should focus on how to determine the charge on the multivalent ion in an ionic compound. Remember, if you have any questions or you do not understand something, ask your teacher!

  Practice Questions

Complete the following practice questions to check your understanding of the concept you just learned. Make sure you write complete answers to the practice questions in your notes. After you have checked your answers, make corrections to your responses (where necessary) to study from.

  1. Provide the correct IUPAC name for each of the following compounds.

    CrBr3
    HgS
    Ni2O3
    MnO2
    Fe3(Po4)2

    CrBr3
    		 chromium(III) bromide
    HgS
    		 mercury(II) sulfide
    Ni2O3 nickel(III) oxide
    MnO2
    		 manganese(IV) oxide
    Fe3(Po4)2 iron(II) phosphate

  Hydrated Ionic Compounds

Did you know that there are some solid ionic compounds that have water as part of their ionic formula?


B5.13 Desiccant pack

Ā© Wikimedia Commons
B5.16 Hydrated copper(II) sulfate

Ā© Wikimedia Commons
B5.17 Dehydrated copper(II) sulfate

Ā© Wikimedia Commons
B5.18 Rehydrating the sam
ple
Desiccant packets are added to substances to absorb water; this prevents mold, mildew, and corrosion. These desiccants are anhydrous forms of hydrated ionic compounds. It is important to note that hydrated compounds are not solutions; they are actually dry solids.

In these compounds, water is bound in the hydrated crystal lattice structure with a fixed ratio of water molecules. If the water is removed, the properties of the substance change and the compound is referred to as the anhydrous form. Some anhydrates are used as drying agents because they absorb water efficiently. The water in the formulas affects the properties of the compound, such as shape, colour, or melting point. Notice that the compound in image B5.16 is blue, whereas once it is dehydrated, it is white, as in image B5.17. Adding water back to the anhydrous form will re-create the hydrated compound, as in image B5.18.

The key guidelines to remember when assigning IUPAC names for hydrates are as follows:

  1. The ionic compound is named first using the guidelines you have already learned.

  2. The second part is often referred to as the water of crystallization and is named by writing "-water (1/n)", where ā€œnā€ is the coefficient in front of the water portion.

  3. When the chemical formula for a hydrated ionic compound is written, the formula for the ionic compound is separated from the waters of hydration by a centred "dot."


Examples

Each example has a video to go with it. To play the video, click on the play icon next to the example.

Naming Hydrates

Name the ionic portion of the hydrate using the rules already learned.

barium hydroxide
Place a dash followed by the word ā€œwater.ā€

barium hydroxide-water
In brackets, write the ratio of ionic compound to water molecules.

barium hydroxide-water (1/8)

Watch this video to see a teacher work through this example.  https://adlc.wistia.com/medias/by7w3jvghh
 


Name the ionic portion of the hydrate using the rules already learned.

calcium nitrate
Place a dash followed by the word ā€œwater.ā€

calcium nitrate-water
In brackets, write the ratio of ionic compound to water molecules.

calcium nitrate-water (1/4)

Watch this video to see a teacher work through this example.  https://adlc.wistia.com/medias/4kn1d6c77z
 

Writing Formulas of Hydrates

Write the formula for the ionic portion of the hydrate using the rules already learned.

Place a dot followed by the coefficient of water molecules.

FeSO4ā€¢7
Write the formula for water: H2O.

FeSO4ā€¢7H2O

Watch this video to see a teacher work through this example.  https://adlc.wistia.com/medias/cy329tvg3n
 


Write the formula for the ionic portion of the hydrate using the rules already learned.

Place a dot followed by the coefficient of water molecules.

Na2CO3ā€¢10
Write the formula for water: H2O.

Na2CO3ā€¢10H2O

Watch this video to see a teacher work through this example.  https://adlc.wistia.com/medias/gzxr95f6hp
 

  Did You Know?

The classical naming system of hydrates uses Greek prefixes.

Copper(II) sulfate-water (1/5) is classically known as copper(II) sulfate pentahydrate.
Ā© Wikipedia
B5.19 Gypsum


B5.20 caste made from plaster of Paris


Gypsum and plaster of Paris are two separate hydrates of the same ionic compound that can be converted from one form to the other. By heating the gypsum to release steam, plaster of Paris is formed; and if water is added to plaster of Paris, gypsum is formed.

Gypsum is a mineral that is used to make drywall for construction.

Once gypsum is heated, it is converted into plaster of Paris.

CaSO4ā€¢2H2O + heat ā†’ CaSO4ā€¢0.5H2O + 1.5H2O (released as steam)

Plaster of Paris is a fine powder that when mixed with water, creates resilient lightweight solid. This is the traditional method for making orthopedic castes.

  Practice Questions

Complete the following practice questions to check your understanding of the concept you just learned. Make sure you write complete answers to the practice questions in your notes. After you have checked your answers, make corrections to your responses (where necessary) to study from.

  1. Provide the correct IUPAC name for each of the following hydrates.


    		 CoCl2ā€¢6H2O
    sodium sulfate-water (1/10)
    nickel(II) nitrate-water (1/9)

    		ZnSO4ā€¢7H2O

    cobalt(II) chloride-water (1/6)
    		 CoCl2ā€¢6H2O
    sodium sulfate-water (1/10)
    		 Na2SO4ā€¢10H2O
    nickel(II) nitrate-water (1/9) Ni(NO3)2ā€¢9H2O
    zinc sulfate-water (1/7)
    		 ZnSO4ā€¢7H2O

  Naming Ionic Compounds

You will be successful with ionic nomenclature if you follow the guidelines and ensure the ion charges combine to create a neutral compound.


B5.21 Salt
You have had the opportunity to look at systematically naming and writing formulas for many compounds. By following guidelines and principles, the seemly overwhelming task of being able to name all ionic compounds has become a manageable task!

In the next lesson, you will learn the guidelines for naming molecular compounds.

Click on The Chemistry Name Game below to view.


The Chemistry Name Game



  Naming Ionic Compounds

Naming Ionic Compounds Ā©Khan Academy


Please work through these questions as a review of ionic nomenclature.

Click on the procedure tab to continue.

  1. Click on the play icon to open the interactive activity. The activity can also be accessed at https://quick.adlc.ca/khan
  2. Work through each of the problems, providing the IUPAC name for each compound.
  3. If you are stuck, there is a hint button that will provide you with guidance. 
  4. Once you have answered all questions, you can either select or you can move on to the next topicā€”Practice: Finding the formula for ionic compoundsā€” found on the bottom left of the screen.


2.4 Assignment

Unit 2 Assignment Lessons 5-8

It is now time to complete the Lesson 5 portion of 2.4 Assignment. This assignment has two parts.

  1. Part 1 Written Portion: Select the preferred document type from the options below. Download and save the assignment on your desktop (or documents folder).

    PDF Document       
  2. Open and print this saved document.
  3. Record your responses in the appropriate textboxes.
  4. When you have completed the assignment, scan it and save it on your desktop (or documents folder).
  5. Once you have completed the written portion of your assignment, click on the button below to go to the submission page.

    Written Portion Submission Page
  6. Part 2 Online Portion: It is now time to complete the Lesson 5 questions of the online portion of this assignment. Click on the button below to go to the online questions of this assignment.

    Online Questions

This assignment is worth ___% of your final grade.