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11/4 What are Lewis structures? - Part II

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mrheffner

The document provides information about Lewis structures and bonding. It discusses the 3-step process for drawing Lewis structures: 1) draw Lewis symbols and count dots, 2) arrange atoms to achieve octets, 3) count dots and draw bonds. Examples are provided for O2, N2, and CCl4. Students then practice drawing Lewis structures and building molecular models in groups. An exit slip assesses understanding of bond types and practice drawing structures for CO2, C2H2, NH3, and SiF4. Homework is to complete a Lewis symbol and ions worksheet.

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Launch: 11/4   Grab your binder and immediately take a seat!   Place homework (practice questions) on desk 1.  Draw the correct Lewis structures for the following atoms. Be sure to use the 3-steps! i.  Br2 ii.  H2S iii.  CCl4
Schedule   We have an exam in 6 days!   We don’t have time to waste!   Follow our 7 class rules   You may not use inappropriate language   If you have a question, ask!
What are Lewis structures? – Part II Mr. Heffner 11/4/09
What are Lewis structures?   Lewis structures are…   pictures of covalent molecules   nonmetal and nonmetal share to get 8 • •  • •  Covalent Bond F- F (dash = 2 electrons) • •  • •  Lewis Structure • • = • •  8
What are Lewis structures?   Cocaine Double Bond   C17H21NO4 2 dashes = 4 electrons
What are Lewis structures?   Large biological molecules are made of   carbon (C) – 4 bonds   nitrogen (N) – 3 bonds   oxygen (O) – 2 bonds   hydrogen (H) – 1 bond   To fill octet C, N, & O sometimes form double/triple bonds   H, I, Br, Cl and everything else = only single bonds
What is a Lewis structure?   There is a 3-step process for creating Lewis structures: 1.  Draw Lewis symbols & count dots 2.  Arrange atoms so they have a full octet   If necessary form a double/triple bond 3.  Count dots & make bonds
Example Draw the Lewis structure for O2   Step 1: Draw Lewis symbols & count dots • •  • •  O O • •  •  • •  •  •  •  12 dots
Example Draw the Lewis structure for O2   Step 2: Arrange atoms so they have a full octet • •  • •  O O • •  •  • •  •  •  7= •  7=
Example Draw the Lewis structure for O2   Step 2: Arrange atoms so they have a full octet • •  • •  •  O O•  • •  •  • •  •  •  •  8 = 8=
Example Draw the Lewis structure for O2   Step 3: Count dots & make bonds • •  • •  •  O O•  • •  •  • •  •  12 dots Double Bond 2 dashes = 4 electrons
Example Draw the Lewis structure for N2
Whiteboards   Work in pairs   Trade-off marker every question   You have 60 seconds to draw the answer   Show all three steps!   Lift board only when prompted
CCl4
CO2
CH2Cl2
N2
Molecular Models   Work with partner 1.  draw all the Lewis symbols 2.  draw the correct Lewis structure 3. !"#$%&''(&"$ a model using toothpicks and)*+$%,-.,"/$ build $ candy 4. 01&2345"-$ a picture of your model (label the 6678$ draw $ atoms) *",9539&$:;&453<(4=$$!<>&9;>,"$!</&>4$ 5.  identify the types of bonds present in molecule $ +3(A>&B$ 01&239,>$ )&.34$+-2@<>4$ Step 1 )&.34$+5";95;"&$ Step 2 !</&>$*395;"&$ Step 3 C<;@>&B$ ?<"2;>,$ D"3E>&F$ $ %0>$ $ $ $ $
Exit Slip 1.  The bonds in water (H2O) are a.  single bonds b.  ionic bonds c.  triple bonds d.  double bonds
Exit Slip 2.  The correct Lewis structure for CO2 is
Exit Slip 3.  Which of the following molecules contains a covalent triple bond? a.  C2H2 b.  I2 c.  NH3 d.  N2
Exit Slip 4.  Bubble in A Then, draw the Lewis structure for SiF4
Exit Slip 5.  Bubble in A Then, draw the Lewis symbol for O2
Homework   Finish Lewis symbol and ions worksheet

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11/4 What are Lewis structures? - Part II

  • 1. Launch: 11/4   Grab your binder and immediately take a seat!   Place homework (practice questions) on desk 1.  Draw the correct Lewis structures for the following atoms. Be sure to use the 3-steps! i.  Br2 ii.  H2S iii.  CCl4
  • 2. Schedule   We have an exam in 6 days!   We don’t have time to waste!   Follow our 7 class rules   You may not use inappropriate language   If you have a question, ask!
  • 3. What are Lewis structures? – Part II Mr. Heffner 11/4/09
  • 4. What are Lewis structures?   Lewis structures are…   pictures of covalent molecules   nonmetal and nonmetal share to get 8 • •  • •  Covalent Bond F- F (dash = 2 electrons) • •  • •  Lewis Structure • • = • •  8
  • 5. What are Lewis structures?   Cocaine Double Bond   C17H21NO4 2 dashes = 4 electrons
  • 6. What are Lewis structures?   Large biological molecules are made of   carbon (C) – 4 bonds   nitrogen (N) – 3 bonds   oxygen (O) – 2 bonds   hydrogen (H) – 1 bond   To fill octet C, N, & O sometimes form double/triple bonds   H, I, Br, Cl and everything else = only single bonds
  • 7. What is a Lewis structure?   There is a 3-step process for creating Lewis structures: 1.  Draw Lewis symbols & count dots 2.  Arrange atoms so they have a full octet   If necessary form a double/triple bond 3.  Count dots & make bonds
  • 8. Example Draw the Lewis structure for O2   Step 1: Draw Lewis symbols & count dots • •  • •  O O • •  •  • •  •  •  •  12 dots
  • 9. Example Draw the Lewis structure for O2   Step 2: Arrange atoms so they have a full octet • •  • •  O O • •  •  • •  •  •  7= •  7=
  • 10. Example Draw the Lewis structure for O2   Step 2: Arrange atoms so they have a full octet • •  • •  •  O O•  • •  •  • •  •  •  •  8 = 8=
  • 11. Example Draw the Lewis structure for O2   Step 3: Count dots & make bonds • •  • •  •  O O•  • •  •  • •  •  12 dots Double Bond 2 dashes = 4 electrons
  • 12. Example Draw the Lewis structure for N2
  • 13. Whiteboards   Work in pairs   Trade-off marker every question   You have 60 seconds to draw the answer   Show all three steps!   Lift board only when prompted
  • 14. CCl4
  • 15. CO2
  • 17. N2
  • 18. Molecular Models   Work with partner 1.  draw all the Lewis symbols 2.  draw the correct Lewis structure 3. !"#$%&''(&"$ a model using toothpicks and)*+$%,-.,"/$ build $ candy 4. 01&2345"-$ a picture of your model (label the 6678$ draw $ atoms) *",9539&$:;&453<(4=$$!<>&9;>,"$!</&>4$ 5.  identify the types of bonds present in molecule $ +3(A>&B$ 01&239,>$ )&.34$+-2@<>4$ Step 1 )&.34$+5";95;"&$ Step 2 !</&>$*395;"&$ Step 3 C<;@>&B$ ?<"2;>,$ D"3E>&F$ $ %0>$ $ $ $ $
  • 19. Exit Slip 1.  The bonds in water (H2O) are a.  single bonds b.  ionic bonds c.  triple bonds d.  double bonds
  • 20. Exit Slip 2.  The correct Lewis structure for CO2 is
  • 21. Exit Slip 3.  Which of the following molecules contains a covalent triple bond? a.  C2H2 b.  I2 c.  NH3 d.  N2
  • 22. Exit Slip 4.  Bubble in A Then, draw the Lewis structure for SiF4
  • 23. Exit Slip 5.  Bubble in A Then, draw the Lewis symbol for O2
  • 24. Homework   Finish Lewis symbol and ions worksheet