foxsciencecentre.weebly.comfoxsciencecentre.weebly.com/uploads/1/2/6/9/12697834/…  · Web viewScience 10: 4.2 Names and Formulas of Compounds. Text: Chapter 4, pages 184-201. Part

Science 10: 4.2 Names and Formulas of Compounds

Text: Chapter 4, pages 184-201

Part A: Chemical Name of Ionic Compounds

-What is an ionic compound?

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-The International Union of Pure and Applied Chemistry regulates the naming of compounds. For example, the chemical name “Potassium Iodide” is governed by the following rules:

a) First Word: Positive ion (metal)

b) Second Word: Negative ion (non-metal)

c) Second Word Ending: Negative ions always end in “ide”

-Try using these rules on the examples below:

Rule MgO Ca3N2

First Word

Second Word Ending

Compound Name

Part B: Chemical Formula of Ionic Compounds

-Examine the chemical formula right. What does it reveal about the ionic compound?

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Science 10: 4.2 Notes Page 1

-There are several steps necessary to create formulas for ionic compounds:

-Try using these rules on the following examples:

Steps Beryllium Sulphide Aluminum Oxide1. Ion and Charge

2. Balance Charges

3. Ration

4. Chemical Formula

Part C: Compounds Containing a Multivalent Metal

-What is a multivalent metal?

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-To show the difference between two ions from the same multivalent metal roman numerals are used to show the ion charge. For example:

a) Nickel (II) Chloride is NiCl2

b) Nickel (III) Chloride is NiCl3

-What do Roman numerals reveal about a metal ion?

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Science 10: 4.2 Notes Page 2

Cross-Over Method

Atom: Al F

Valence: +3 -1

Formula: AlF3

Part D: Steps for Writing Formulas of Ionic Compounds Containing a Multivalent Metal

-Use these steps to try the following examples.

Steps Iron (III) Bromide Lead (IV) Oxide1. Ion and Charge

2. Balanced Charges

3. Ration

4. Formula

Science 10: 4.2 Notes Page 3

Part E: Steps for Naming Ionic Compounds that Contain a Multivalent Metal

-Use these steps to try the following examples.

Steps CoCl2 Ni2O3

1. I.D. Metal

2. Identify the Ions

3. Ion Ratios

Science 10: 4.2 Notes Page 4

4. Negative Ion Charge

5. Balance Positive and Negative Charges

6. Compound Name

Part F: Polyatomic Ions

-A polyatomic ion is made of more than one type of atom joined by covalent bonds. See the Lewis Diagram of Calcium Carbonate above.

-The table below lists the names of polyatomic ions. You do not need to memorize these!

-Below are the steps for naming an ion containing a polyatomic

ion:

Steps Cu2SO4 NH4CH3COO NaOH (NH4)2CO3

1. Identify Positive Ion, check if multivalent and write name2. Identify Negative Ion and write its name3. Write the compound name

-Below are the steps for writing the formula of compounds with polyatomic ions.

Science 10: 4.2 Notes Page 5

Steps Potassium Permanganate

Lead (II) Perchlorate

1

2

3.

4.

5.

Part G: Names and Formulas of Covalent Compounds

-The chemical formula of covalent compounds shows the number of atoms present.

-How many atoms of each element are present in H2O2(Hydrogen Peroxide)? Two H and two O.

-How would the formula H2O2 be treated if it represented an ionic bond?

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Part H: Naming Binary Covalent Compounds

-A binary covalent compound contains two non-metals joined by one or more covalent bonds.

-As these compounds can consist of two or many atoms, prefixes are used to show the number of atoms of each element present.

-Below are the steps for naming binary covalent compounds that do not contain hydrogen:

Steps CO N2O3 Cl2O1. Name the first element

2. Name the

Science 10: 4.2 Notes Page 6

Number Prefix1

2

3

4

5

6

7

8

9

10

second element and change the ending to ide3. Add the appropriate prefix

*Exceptions to Step 3:-No prefix for the first element if there is only one atom-Prefix mono becomes mon if it is placed before oxide

-The naming of covalent compounds containing hydrogen will be covered in Chapter 5.

Part I: Formulas for Binary Covalent Compounds

Steps Chlorine Monofluoride

Dinitrogen Tetraoxide

Sulphur Dioxide

Selenium Difluoride

1. Identify the first non-metal and use a subscript

to show the number of atoms

1. Identify the second non-metal and use a subscript

to show the number of atoms

3. Write the formula

*Refer to text pages 196 and 197 for hints in naming ionic and covalent compounds

Science 10: 4.2 Notes Page 7