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Warm Up…what do you remember?

Warm Up…what do you remember?. Why do bonds form? What is the difference between ionic and covalent bonds?. Warm Up…what do you remember?. Why do bonds form?. What is the difference between ionic and covalent bonds?. Draw the Lewis Structures and show the behavior of the electrons.

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Warm Up…what do you remember?

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  1. Warm Up…what do you remember? • Why do bonds form? • What is the difference between ionic and covalent bonds?

  2. Warm Up…what do you remember? Why do bonds form?

  3. What is the difference between ionic and covalent bonds?

  4. Draw the Lewis Structures and show the behavior of the electrons. Sodium and Bromine Fluorine and oxygen (you will need 2 F)

  5. Covalent Compounds Nonmetal bonding with another nonmetal Electronegativity difference less than 1.67 Electrons being shared

  6. Formation of Covalent Bond

  7. Bond Stability

  8. Properties of Covalent Compounds • low melting point • low boiling point • many are gas and liquid at room temp • typically do not conduct electricity when dissolved in water This is due to the fact that forces of attraction between molecules are much weaker when the electrons are being shared.

  9. Ionic vs covalent Visual Concepts

  10. Warm Up- Write the correct formulas from the names. • Copper (III) iodide • Sodium oxide • Calcium nitride • Chromium (II) oxide • Iron (III) sulfide When do we need to use Roman Numerals in the name of an ionic compound?

  11. Discuss Signs…

  12. Draw the MO diagram for Carbon and Oxygen… What do the electrons do?? Do we need to worry about covalent compounds being neutral?

  13. Are the electrons being shared equally??

  14. Polar or Nonpolar? Nonpolar- electrons are shared equally. Polar- electrons are not shared equally.

  15. Octet Rule • Noble gases: have filled valence shells = 2 (He) or 8 e- • Octet Rule tells us that chemical compounds tend to form so that atoms obtain an octet of e- in its highest energy level. Visual Concepts

  16. Lewis Structure Rules • Add up total number of valence e- • Pick central atom and create the bonds • Surround the adjacent atoms. • Put extra electrons on the central atom. • Beg, borrow or steal so that all the atoms are stable (have a complete octet). • Make sure the number of valence e- you started with are the number you used!

  17. Lets do… CH4 SiF4 NCl3

  18. Draw the Lewis Structures for the following molecules… CH3F SiCl4 How many shared electrons? How many unshared electrons? Are the electrons shared equally?

  19. Dipoles Indicate polarity- dipole points to the most electronegative atom! Show the unequal distribution of charge

  20. Exceptions • Borontrifluoride BF3 • PF5 and SF6 can expand the shell and share more electrons. (10 and 12 respectively)

  21. Diatomic Molecules You must memorize these!! H2 N2 O2 F2 Cl2 Br2 I2 (At2) Magnificent 7— I won’t hold you responsible for astatine, just know that trends in a group apply!

  22. Naming Covalent Compounds Covalent compounds are molecules or molecular compounds… Indicate the number of each atom using prefixes….. …change the end of the name to “ide”

  23. Covalent Prefixes Use the prefixes! 1- mono 6- hexa 2- di 7- hepta 3- tri 8- octa 4- tetra 9- nona 5- penta 10- deca Examples: NO SiCl4

  24. Practice Formulas to names Names to formulas 1. Carbon tetrachloride 2. Dinitrogen monoxide 3. Dinitrogen tetroxide 4. Phosphorus triiodide 5. Sulfur heptafluoride • SO3 • ICl3 • PBr5 • CO • CO2

  25. Homework- You can do these! H2Se CH2Cl2 Silicon Tetrachloride HCl Fluorine CH4 NH3 Silicon Tetrachloride Chlorine

  26. Warm Up- Thursday Write the names from the formulas… 1. BaSO4 2. MnO4 3. SiO2 4. PO 5. NiPO4

  27. Questions on Homework? Lewis Structure WS… Naming Covalent Compounds WS

  28. Forming Multiple Bonds CO2 N2O

  29. Multiple Covalent Bonds • Bond length and strength • Triple bonds are the shortest (pm) and have the most Energy (kJ/mol) • Single bonds are the longest (pm) and have the least amount of Energy (kJ/mol)

  30. Sigma s and Pi p bonds • Sigma (s) bonds are single bonds • Pi (p) bonds are the bonds that follow in a multiple bond situation

  31. Now you try… CO Oxygen

  32. Polyatomic ions Draw the Lewis Structures for the following polyatomic ions. Phosphate Hydroxide LS of ions are indicated using [ ] and charge

  33. Polyatomic ions Examples

  34. Warm Up: Draw the Lewis Structures and indicate the dipoles… • CH2F2 2. F2 3. NO31- Indicate the number of shared and unshared pairs on each molecule. .

  35. Resonance Structures • Some molecules cannot be correctly identified by a single Lewis structure • When you can draw two mirror images, you probably have a resonance structure • For example: Ozone O3 Visual Concepts

  36. Draw the Resonance Structures for Selenium Trisulfide

  37. Questions on the LS WS?? How did you do on the polyatomic ions??

  38. Acids to memorize… Hydrochloric- HCl Acetic Acid- HC2H3O2 Nitric Acid- HNO3 Sulfuric Acid- H2SO4 Carbonic Acid- H2CO3 Phosphoric Acid- H3PO4

  39. Fold paper so that you have 6 squares on each page. Write the compound formulas in each box as indicated on the board. Building Covalent Molecules Activity

  40. Just a few things from last semester… • Your feedback is very important to me! a. Students like- CB, notes, activities b. Mixed reactions- POGILS, Projects and homework amount. c. Students didn’t like- IB cut and paste, worksheet assignment/collection. • Performance Assessment / Final. • Writing in science. • What’s new in the room?

  41. Draw the Lewis Structure for each molecule. Build the molecule using the kits. Determine the Electronegativity of each atom and determine bond polarity- draw the dipoles on LS. Draw the 3-D molecule. Determine the molar mass of each molecule. Building Covalent Molecules Activity

  42. Warm Up- Write the names from the formulas… 1. BaSO4 2. MnO4 3. SiO2 4. PO 5. NiPO4 Be sure you are reviewing your Ionic Bonding… all is fair game for the test next week.

  43. Review Questions? Test

  44. Warm Up Determine the formula • Calcium hydroxide • Vanadium (IV) oxide • Phosphorus tribromide • Chlorine • Zinc sulfide Determine the name • SrO • FePO4 • PO3 • HC2H3O2 • O2

  45. How did you do? Determine the formula • Ca(OH)2 • VO2 • PBr3 • Cl2 • ZnS Determine the name • Strontium oxide • Iron(III) phosphate • Phosphorus trioxide • Acetic acid • Oxygen

  46. Just a few things from last semester… • Your feedback is very important to me! a. Students like- CB, notes, activities b. Mixed reactions- POGILS, Projects and homework amount. c. Students didn’t like- IB cut and paste, worksheet assignment/collection. • Performance Assessment / Final. • Writing in science. • What’s new in the room?

  47. Molecular Geometry VSEPR Valence Shell, Electron Pair Repulsion Theory

  48. VSEPR • How a molecule “looks” in real space (3D). • Shape is based upon electron domains (where electrons are). Bonds (doubles/triples count as one domain) Unshared electron pairs- actually take more space.

  49. You need to remember… • Electron domains repel each other. • Unshared pairs repel more than bonding pairs. • Domains orient themselves as far away from each other as possible.

  50. VSEPR Let’s use balloons to figure out the molecular geometry of various compounds!

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