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GRC Mini Grant Prototype Storyboard #2

GRC Mini Grant Prototype Storyboard #2. Bond Polarity and Molecular Polarity. Bond Polarity and Molecular Polarity Outline 2.1 Understanding Electronegativity - place arrows, recording (slides 4-6) 2.2 Electron Distribution - drag to draw cloud (slides 7-10)

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GRC Mini Grant Prototype Storyboard #2

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  1. GRC Mini Grant Prototype Storyboard #2 Bond Polarity and Molecular Polarity

  2. Bond Polarity and Molecular Polarity Outline 2.1 Understanding Electronegativity - place arrows, recording (slides 4-6) 2.2 Electron Distribution - drag to draw cloud (slides 7-10) 2.3 cand Polarity - decide if distribution is symmetrical, calculate sort bonds from lowest to highest electronegativity, determine polarity recording (slides 11 - 15) 2.4 Examine Three Molecules - make polarity prediction, assign +/ -, watch vector resolution animations, recording (slides 16-25) Tracking Sheet 2.0_v1.ppt by rjh 7.1.08 2.0_v1.ppt by blg 7.12.08

  3. Learning Goals • - Students will be able to predict if a bond is polar or non-polar. • Students will be able to predict if a molecule is polar or non-polar. • Students can account for polarity of individual bonds in a molecule and then determine whether that molecule is symmetric or asymmetric. Barbara Gonzalez: Suggestions for learning goals expressed in terms that are amenable to assessable outcomes. After completing this module, the learner will be able to: -Predict if a covalent bond is polar or nonpolar. -From molecular geometry and polarity of individual bonds, determine if a molecule has a symmetric and asymmetric electron distribution. -Predict if a molecule is polar or nonpolar.

  4. 2.1.1 Indicate which atom in each bond is the more electronegative by dragging a black arrow to the pair and orienting it so that the arrow head points to the more electro- negative atom. C-H O-H N-H

  5. 2.1.2 Indicate which atom in each bond is the more electronegative by dragging a black arrow to the pair and orienting it so that the arrow head points to the more electro- negative atom. Looks like you’re having trouble, would you like information about the periodic trend of electronegativity?  yes  no C-H C-H N-H

  6. 2.1.3 Indicate which atom in each pair is the more electronegative by dragging a black arrow to the pair and orienting it so that the arrow head points to the more electro- negative atom. Barbara Gonzalez: The arrows are pointing to the electropositive atom in each bond. I copied this slide to create 2.1.3A with the arrows oriented correctly. C-H O-H N-H Is this your final answer?  yes  no Please record your answer to the following question: What is meant by electronegativity? Explain how you knew which way to point your arrows. next

  7. 2.1.3A Indicate which atom in each pair is the more electronegative by dragging a black arrow to the pair and orienting it so that the arrow head points to the more electro- negative atom. Barbara Gonzalez: What do we do if the student responds incorrectly? Should we consider a tutorial here for the future? C-H O-H N-H Is this your final answer?  yes  no Please record your answer to the following question: What is meant by electronegativity? Explain how you knew which way to point your arrows. next

  8. 2.2.1 Referring to the directional arrows you drew previously, use your mouse to drag the gray cloud and create an electron distribution for each molecule. Click next when you’re ready to summon the next molecule. Barbara Gonzalez: Referring to the directional arrows that you drew previously, use your mouse to drag the gray cloud to represent the electron distribution for each chemical bond. The cloud should be more larger(?) where the probability of finding electrons more often is greatest. Click NEXT when you are ready to summon the next chemical bond. 1 of 4 C-H C -H next

  9. 2.2.2 Referring to the directional arrows you drew previously, use your mouse to create an electron distribution for each molecule. Click next when you’re ready to summon the next molecule. 1 of 4 2 of 4 C-H O-H C -H H - O next Barbara Gonzalez: Referring to the directional arrows that you drew previously, use your mouse to drag the gray cloud to represent the electron distribution for each chemical bond. The cloud should be more larger(?) where the probability of finding electrons more often is greatest. Click NEXT when you are ready to summon the next chemical bond.

  10. 2.2.3 Referring to the directional arrows you drew previously, use your mouse to create an electron distribution for each molecule. Click next when you’re ready for the next molecule. 1 of 4 2 of 4 3 of 4 C-H O-H N-H C -H H - O H - N next Barbara Gonzalez: Referring to the directional arrows that you drew previously, use your mouse to drag the gray cloud to represent the electron distribution for each chemical bond. The cloud should be more larger(?) where the probability of finding electrons more often is greatest. Click NEXT when you are ready to summon the next chemical bond.

  11. 2.2.4 Referring to the directional arrows you drew previously, use your mouse to create an electron distribution for each molecule. Click next when you’re ready to proceed. 1 of 4 2 of 4 3 of 4 3 of 4 C-H O-H N-H H-H C -H H - O H - N H -H Barbara Gonzalez: Referring to the directional arrows that you drew previously, use your mouse to drag the gray cloud to represent the electron distribution for each chemical bond. The cloud should be more larger(?) where the probability of finding electrons more often is greatest. Click NEXT when you are ready to summon the next chemical bond. next

  12. 2.3.1 Identify the symmetry of the electron distributions in the four examples by clicking on either symmetric or asymmetric fin the green boxes below each one. C - H O - H N - H H - H  symmetric  asymmetric  symmetric  asymmetric  symmetric  asymmetric  symmetric  asymmetric Placeholder for a research question dealing with symmetry (student open response). Barbara Gonzalez: Please record your answer to the following questions:What do you think is meant by the term symmetric? Explain why the O-H bond is considered to be asymmetric? next

  13. 2.3.2 Calculate the difference in electronegativity () for each example using the values in the table. Barbara Gonzalez: Calculate the difference in electronegativity () for each bond using the values in the table. C - H O - H N - H H - H  symmetric  asymmetric  symmetric  asymmetric  symmetric  asymmetric  symmetric  asymmetric  = ____________  = ____________  = ____________  = ____________ Barbara Gonzalez: Include label/heading in the table. See added column below. next

  14. 2.3.3 Sort the bonds in increasing order of the difference in electronegativity ( ) by dragging each block into the empty boxes below, from lowest to highest. C - H O - H N - H H - H  symmetric  asymmetric  symmetric  asymmetric  symmetric  asymmetric  symmetric  asymmetric  = 0.4  = 1.4  = 0.9  = 0 lowest highest next

  15. 2.3.4 You can determine whether a bond is polar or non-polar if you know the difference in electronegativity () between the two bonded atoms. If the difference value is less than 0.5, the bond is non-polar. If it’s greater, the bond is polar. Identify the polarity of each bond below by clicking either polar or non-polar in the purple boxes. H - H N - H O - H C - H  symmetric  asymmetric  symmetric  asymmetric  symmetric  asymmetric  symmetric  asymmetric  = 0  = 0.4  = 0.9  = 1.4  polar  non-polar  polar  non-polar  polar  non-polar  polar  non-polar

  16. 2.3.5 You can determine whether a bond is polar or non-polar if you know the difference in electronegativity () between the two bonded atoms. If the difference value is less than 0.5, the bond is non-polar. If it’s greater, the bond is polar. Identify the polarity of each bond below by clicking either polar or non-polar in the purple boxes. H - H N - H O - H C - H  symmetric  asymmetric  symmetric  asymmetric  symmetric  asymmetric  symmetric  asymmetric  = 0  = 0.4  = 0.9  = 1.4  polar  non-polar  polar  non-polar  polar  non-polar  polar  non-polar  Please record your answer to the following: Explain how the difference in electronegativity and the electron distribution relate to the polarity of the bond. next

  17. 2.4.1 Now you will examine the geometry of three different molecules: carbon tetrachloride, chloroform, and water. You will begin with carbon tetrachloride (CCl4), which has an electron pair and molecular geometry that is tetrahedral. A ball and stick representation of the molecule appears below. Drag the arrows to each bond, using the electronegativity values to indicate the direction of the arrow (the arrow head should point to the more electronegative atom). CCl4 CHCl3 H2O Carbon tet diagram here Is the electron distribution in all of the bonds symmetric or asymmetric?  yes  no next

  18. 2.4.2 Answer the questions in the orange box by typing your answers. Once you’ve made your predictions, assign a + and a - to each atom in all four bonds on the diagram below by dragging the symbols onto the molecule. CCl4 CHCl3 H2O Based onthe asymmetry of the bonds, would you predict that the four bonds are polar or non-polar? ____________ Is it possible for all four bonds in the molecule to be polar and the entire molecule to be non-polar? ____________ Based on that, do you predict the molecule is polar is non-polar? ___________________ - + Carbon tet diagram here next

  19. 2.4.3 Now you will examine chloroform (CHCl3) which is a tetrahedral molecule. The ball and stick figure appears below. Using the electronegativity values in the table, drag the arrow to point to the more electronegative atom in each bond. CCl4 CHCl3 H2O Chloroform diagram here Is the electron distribution in all of the bonds symmetric or asymmetric?  yes  no next

  20. 2.4.4 Answer the questions in the orange box and then assign a + and a - to each atom in all four bonds on the diagram below. CCl4 CHCl3 H2O Based onthe asymmetry of the bonds, would you predict that the four bonds are polar or non-polar? ____________ Is it possible for all four bonds in the molecule to be polar and the entire molecule to be non-polar? ____________ Based on that, do you predict the molecule is polar is non-polar? ___________________ - + Chloroform diagram here next

  21. 2.4.5 Now you will examine water (H2O) which as an electron pair and molecular geometry that is tetrahedral. A ball and stick representation of the molecule appears below. Drag the arrows to each bond, using the electronegativity values to indicate the direction of the arrow (the arrow head should point to the more electronegative atom). CCl4 CHCl3 H2O Barbara Gonzalez: Now you will examine water, (H2O), which has an electron pair geometry that is tetrahedral and a molecular geometry that is bent. water diagram here Is the electron distribution in all of the bonds symmetric or asymmetric?  yes  no

  22. 2.4.6 Answer the questions in the orange box and then assign a + and a - to each atom in all four bonds on the diagram below. CCl4 CHCl3 H2O Based onthe asymmetry of the bonds, would you predict that the four bonds are polar or non-polar? ____________ Is it possible for all four bonds in the molecule to be polar and the entire molecule to be non-polar? ____________ Based on that, do you predict the molecule is polar is non-polar? ___________________ - + Water diagram here next

  23. 2.4.7 Click start on the movie below to determine the polarity of CCl4 and the accuracy of your prediction. When you’re ready, select CHCl3 and then H2O to see their movies. CCl4 CHCl3 H2O Vector resolution animation Based on the asymmetry of the bonds, would you predict that the four bonds are polar or non-polar? ______YES______ Is it possible for all four bonds in the molecule to be polar and the entire molecule to be non-polar? _______NO_____ Based on that, do you predict the molecule is polar is non-polar? ______YES______ start >

  24. 2.4.8 Click start on the movie below to determine the polarity of the molecule and the accuracy of your prediction. CCl4 CHCl3 H2O CCl4 Vector resolution animation Based on the asymmetry of the bonds, would you predict that the four bonds are polar or non-polar? ______YES______ Is it possible for all four bonds in the molecule to be polar and the entire molecule to be non-polar? _______NO_____ Based on that, do you predict the molecule is polar is non-polar? ______YES______ next

  25. 2.4.9 Click start on the movie below to determine the polarity of the molecule and the accuracy of your prediction. CCl4 CHCl3 H2O CCl4 CHCl3 Based on the asymmetry of the bonds, would you predict that the four bonds are polar or non-polar? ______YES______ Is it possible for all four bonds in the molecule to be polar and the entire molecule to be non-polar? _______NO_____ Based on that, do you predict the molecule is polar is non-polar? ______YES______ Vector resolution animation next

  26. 2.4.10 Click on any of the movie icons to review. Answer the final question below. CCl4 CHCl3 H2O stage Were your predictions correct? Why or why not?

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