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LARN 067 C17D3

Start the following in class:

1. In your Journal Notebook write your journal entry on sheets of three holed 8.5 inch by 11 inch ruled paper.  In the upper right corner white space of each upward facing page, use a blue or black pen to write your hand in number within a circle followed by your name.  To the left of the marginal line, print J67 and circle it. Each journal entry should either be at least a paragraph of exemplary writing and penmanship concerning a single topic, or be a concept map relating chemistry terms. Begin each day’s paragraph with a topic sentence, follow with explained instances, and close with a focused summary statement. The required journal focus questions J67 for today is

a. How does one use the knowledge of the number of valence electrons in a molecule or polyatomic (molecular) ion and the idea that atoms of the representative elements generally react until they attain a completely their outermost shell (by gaining, losing, or sharing electrons) [the “duet/octet rule”] to calculate the number of shared (a.k.a. bonding) electrons and the number of unshared (a.k.a. nonbonding) electrons?

b. Show an example of using the knowledge of the number of valence electrons in a molecule or polyatomic (molecular) ion and the duet/octet rule to calculate the number of shared (a.k.a. bonding) electrons and unshared (a.k.a. nonbonding) electrons in a molecule of five or less atoms.

2. Do all the pages in the chapter 8 Formative Test on Covalent Bonding as a formative assessment to find out some of the things that you do and do not know, and not as a research project.

  • If you did not obtain a section review packet for the chapter in class, go to MNSD Google Drive > Student Resources > Formative Tests and print off a copy of the test for the chapter you are studying.  Each chapter test is identified by a name whose last two digits is the chapter number.  When you open the chapter formative test the first page will have the words “Chapter Test A” in the title.
  • For each question or problem challenge, either answer the question to the best of your ability using one or more full sentences, or answer the problem to the best of your ability by recording any numbers and units together with the mathematical operations performed in symbolic terms, along with the solution to the problem which should be circled.
  • After doing the formative test, but before you demonstrate your understanding on our class’ chapter test, you will check all your responses using green ink check marks √ for each correct response, and by lining out (striking trough) and inserting improved text in green ink when you think the suggested response expresses your present understanding in a better way.    In that way make sure that you understand each idea that you originally did not have a complete understanding of.  Then you will be able to study more efficiently by studying that which you corrected in green ink.

Recommended for those who have time left in their 45 minute study period, but not required of all:

1. Different classes are in different places in doing the laboratory activity in which you are to build and examine three dimensional models of covalent molecules. If you have fallen behind the place where your teacher expects you to be, you need to catch up by constructing each framework model for lab activity U05-5 (A28LA), showing it to your teacher for feedback, and fixing anything up on your formulas and observations sheet that was suggested.  If you missed class or have not yet completed columns 3, 4, and 5 on both sides of your laboratory Results page, you may need to attend help class so that you can show each of your models and your laboratory Results page to your teacher and in that way have your understanding of each model checked.

In Column 5, the third column from the right:

  • Construct the dash/dot formula for each molecuIe from the Lewis Dot Formula that you constructed in Column 4.
  • Record the electronegativity of each different element present in the molecule near the symbol for the element.
  • Write the arithmetic for the difference in electronegativities once for each different pair of bonded atoms
  • Record the name given to the shape of the arrangement of atoms around each central atom in the molecule.

Each row in Column 6 can be filled in during your chemistry class period, in help class, or by your prediction from the dash/dot formula in Column 5 and a table of electronegativities.

If you do this in your chemistry classroom, start with the substance named in row one and put together a model for a molecule of each of the 15 substances in such a way that the model represents the  dash/dot structure given in Column 5.

      From the model you have constructed, or from the dash/dot formula you have constructed in Column 5, in Column 6:

    • Draw a crude sketch of the model using an unlabeled circle to represent each atom’s kernel or the nucleus of a hydrogen atom and a dash either to represent a bonding straw or to represent a nonbonding electron or nonbonding (a.k.a. lone) pair of electrons shown by an unused prong attached to an atom center, and
    • Record the name given to the shape of the arrangement of atoms around each central atom in the molecule.
    • Draw a small arrow originating near the symbol for the atom of lower electronegativity and pointing toward the symbol for the atom of higher electronegativity to which it is bonded.
    • Compare the models actual shape around each central atom recorded in Column 6, the second to the right column, to its predicted shape recorded in Coumn 5, the column to its left.
    • Compare and checkoff in green ink the shape, bond types, bond angles, and nonbonding electron groups in each model’s sketch column (Column 6) to the corresponding dot/dash formula shown in the column immediately to their left (Column 5).
    • Analyze any discrepancies and make corrections.
  • Correct any incorrect prediction, or incorrect model description.

In Column 7, the rightmost column,

    • State whether the bond dipole moments (a.k.a. bond polarities) do cancel or do not cancel if there are two or more bonds in the molecule.
    • Based on the magnitude and direction of any bond polarities, identify each molecule as a nonpolar molecule or as a polar molecule.
  •  State the justification for each prediction using words similar to those given in step 10 of the Instructions for Building Models for Covalently bonded Polar and Non-polar Molecules found on page 5 of your laboratory guided inquiry handout U05-5.

If you predicted Column 6 from your dash/dot formula in Column 5, when you get to class start with the substance named in row one and put together a model for a molecule of each of the 15 substances in such a way that the model represents that  dash/dot structure given in Column

2. Each person must bring each model and its description on the observation sheet to your teacher and listen to and heed any suggestions that your teacher makes before beginning the Analysis and Conclusions section of this laboratory activity.

After you have shown all your two and three dimensional models to your teacher and have received his ink mark on each one, use full sentences to write accurate responses to the three Analysis questions.  Read each question carefully and make sure that you understand what is being asked before fashioning your well thought out and expressed responses to the questions.

To word process your Analysis, Conclusions, and References sections using the template for U05-5,  locate it at Google Drive > Student Resources > Laboratory Activities > Honors Chemistry Guided Inquiries, make a copy of it, download it, and rename it as described in the instructions given below.

For your Conclusions, go on and clearly state each original Problem question and the evidence and reasoning in support of your response to each Problem question. Be sure to offer a thorough discussion of each Problem question that leads up to your stated answer in each case.