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2/15/11:Have out chart to check

2/15/11:Have out chart to check. Objective: Describe the change in energy and stability that takes place as a covalent bond forms . Catalyst: 1. In which type of bond are electrons shared equally? In which type of bond does one atom take an electron from another atom? Homework:

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2/15/11:Have out chart to check

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  1. 2/15/11:Have out chart to check Objective: Describe the change in energy and stability that takes place as a covalent bond forms. Catalyst: 1. In which type of bond are electrons shared equally? • In which type of bond does one atom take an electron from another atom? Homework: By Friday, questions 1-14 on page 198 and cornell notes on pages 194-198 Questions 1-4 and  8-10 on page 198 can be completed

  2. Agenda • Catalyst (7) • Notes (20) • Bonding Cartoon (20)

  3. What are covalent bonds? • Bonds between neutral atoms • Neither atom can remove electrons from the other, so they share • Become more stable because they have full electron shells How are they similar to ionic bonds? How are they different?

  4. How are covalent bonds formed? • Most atoms are unstable and have high potential energy • The protons of one atom attract electrons of other atoms to increase stability • Positive charges of the nucleus repel one another • When these forces balance the bond is stable

  5. What is bond length? • The average distance between two bonded atoms that has minimum potential energy • Atoms vibrate back and forth at about this distance • What forces must be equal at this distance? • Why might this length vary?

  6. What is bond energy? • The energy required to break a bond between 2 atoms • The closer the atoms, the harder to break • What is the association between bond length and bond energy?

  7. Cartoon • As a group, draw a cartoon representing two atoms bonding covalently. Be sure to include: • Type of covalent bond • Two forces: Attractive and Repelling • Protons • Nucleus • Electrons

  8. Day 2

  9. 2/16/11 Objective: Distinguish between polar and nonpolar covalent bonds based on electronegativities. Catalyst: • What are the two forces that occur in a covalent bond? • Why is bond length measured as a an average distance? Homework: By Friday, questions 1-14 on page 198 and cornell notes on pages 194-198 Questions 5 and 11-14 on page 198 can be completed

  10. Agenda • Catalyst (7) • Notes (20) • Bonding questions (15)

  11. What is electronegativity? • The ability to attract electrons • Differences between atoms determine type of bond • When do you think atoms will share electrons? • When do you think an atom will take electrons from another?

  12. What are the types of covalent bonds? • Nonpolar covalent bonds share electrons equally • Polar covalent bonds share electrons non-equally • What can you say about the electronegativities of each of these bond types? • Which type of bond is more like an ionic bond?

  13. What are the charges of atoms in covalent compounds? • If electrons are shared equally, atoms are neutral • If electrons are shared unequally atoms have a partial charge • Molecules with partial charges are called dipoles • Will high or low electronegative atoms have a partial negative charge? Partial positive charge?

  14. How is polarity related to bond strength? • Greater polarity is related to greater bond strength • Which types of bonds will be strongest? Weakest?

  15. Electronegativity difference and bond type • Electronegativity difference determines bond type • 0 to 0.5 are non-polar covalent • 0.5 to 2.0 are polar covalent • Over 2.0 are ionic • Using the chart on the next page, determine the bond types of the following compounds and name the positive and negative atom

  16. Hydrogen and Fluorine Lithium and Oxygen Nitrogen and Oxygen Nickel and Cobalt Sodium and Phosphorus Zinc and Chlorine

  17. Day 3, properties and bond strength • aa

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