1. Module 1 Intro

1.21. Page 3

Module 1: Lesson 4

Module 1—Chemical Foundations

Read

 

The prefix naming system is only used for a limited number of molecular compounds. There are millions of molecular compounds that cannot be named using this system, for example, those composed of more than two elements. Other naming systems or memorized common names are used to name these other molecular compounds.

 

Review “Table 3” on page 34 of your textbook. You may wish to make a copy of this table for your notes and memorize it, as these substances will often be referred to during this course and also in Chemistry 30.

 

Electronegativity

 

In Lesson 3 you were introduced to the concept of electronegativity. What effect does a difference in the attraction for the shared electrons between atoms participating in a covalent bond have on the bond and on the molecule that results from these bonds?

 

In the textbook, read “Electronegativity and Bond Polarity” on pages 99 and 100. Work through “SAMPLE problem 3.4” on page 100.

 

Self-Check

 

SC 5. Complete “Practice” problems 9 and 10 on page 100 of the textbook.

 

SC 6. Prepare a chart that summarizes the two types of covalent bonds, what distinguishes each type of bond, and two examples of each type of bond.

 

Check your work.
Self-Check Answer

 

SC 5.

 

9.


  1. H

    Cl

    Difference in Electronegativity

    Classification

    2.2

    3.2

    1.0

    polar covalent


  2. C

    H

    Difference in Electronegativity

    Classification

    2.6

    2.2

    0.4

    polar covalent


  3. N

    O

    Difference in Electronegativity

    Classification

    3.0

    3.4

    0.4

    polar covalent
    4.  

  4. I

    Br

    Difference in Electronegativity

    Classification

    2.7

    3.0

    0.3

    polar covalent
    5.  

  5. Mg

    S

    Difference in Electronegativity

    Classification

    1.3

    2.6

    1.3

    		 ionic bond (The bond is between a metal and a non-metal.)
    6.  

  6. P

    H

    Difference in Electronegativity

    Classification

    2.2

    2.2

    0

    nonpolar covalent

10.


  1. H

    Br

    Difference in Electronegativity

    Classification

    2.2

    3.0

    0.8

    polar covalent
    2.  

  2. Li

    F

    Difference in Electronegativity

    Classification

    1.0

    4.0

    3.0

    		 ionic bond (The bond is between a metal and a non-metal.)
    3.  

  3. C

    C

    Difference in Electronegativity

    Classification

    2.6

    2.6

    0

    nonpolar covalent

     

SC 6.

 

Type of Covalent Bond

nonpolar covalent

polar covalent

Distinguishing Aspect

The electronegativities of atoms involved are identical.

The electronegativities of atoms are different.

Examples

O2 , F2

N-H, C-Cl

 

Discuss

 

Copy the table below. In the third column, write a justification that explains the type of bond formed in each of the electronegativity differences presented. Use your class discussion area to share your completed table with your classmates. Look at the tables of at least two other classmates. Are similar justifications made by the other students? You may wish to revise your justification. Once your table is complete, place a copy of it in your chemistry folder.

 

Electronegativity Difference

Type of

Bond Formed

Justification for Type of Bond Formed

0

non-polar covalent

 

greater than zero to 1.6

polar covalent

 

greater than 1.6 to 2.1
  • ionic if a metal is involved

  • polar covalent if no metal is involved

 

greater than 2.1

ionic

 

 

Module 1: Lesson 4 Assignments

 

Retrieve the Lesson 4 Assignment you saved to your course folder earlier in this lesson. Complete the questions in the assignment. Save a copy of your answers to your course folder.

 

Once you have completed all of the questions, submit your work to your teacher.